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Roger
03-03-2007, 03:40 PM
I have a LB Dura-Force powered 21" hand mower, SP. It is about four seasons old, but has been run pretty hard. It has been through some difficulties (no need to spell them out here), but it ran pretty well last season ... until the last month. I did not spend much time, but lived with the problem as it did not impact productivity in any great way.

The primary problem was lack of speed control with the throttle. After a little searching, I found the throttle butterfly to be worn, the shaft passing through the throat of the carb, with the fin on top catching air flow from the flywheel, and a blind pin on the bottom. The real problem was the pin on the bottom was badly worn, out of round and not fitting tightly into the hole. The movement of the entire shaft caused the bottom of the fin to interfere with the slider mechanism. This mean uneven speed control.

I replaced the shaft, and the blind pin fit pretty well into the hold. Apparently most wear was on the pin, not the hole. The new shaft now moved freely and did not interfere with the slider. The shaft is the only part I replaced.

However, the speed control was not working well. Movement of the lever on the handle made no difference in engine speed. Sometimes the engine speed would race, and then settle to the proper speed. It was if the throttle was catching someplace, but that place was not obvious. My thought was that the disc that slides through the slot in the shaft was misshapen from my removal and reinsertion.

This Winter I got new parts, a new shaft with fin (same one replaced in the last month of the season), a new throttle disc, a new throttle spring.

I put all the pieces together yesterday, and got the engine running. However, the problematic characteristics remain. I am unable to get proper speed control with the thumb wheel. I have no tachometer, so must judge speed by ear. I am sure it is running a bit too fast, but any movement on the wheel makes no difference. Also, the speed control lever (moving the slider on top of the air box) makes no difference in engine speed. The shaft with the fin seems to be free, has spring tension, and the disc fits well in the slot (don't think it is providing any interference).

At this point, I am at a loss what to try next. I have removed and reinstalled this carb many times, and did likewise on another LB of former years. My point is that I am working with familiar parts and mechanisms. I have had successes in changes before, mostly making spring replacements.

Obviously, none of my explanations will make any sense, UNLESS you have had some experience with these engines.

Anybody have a suggestion for next step?

I am not sure if an entire carb can be bought as an assembly. If so, maybe it is time to trash this one in favor of a new assembly. My patience is pretty thin with this engine. However, I do want to have it running in top condition when the season begins. It is a workhorse for us, often running 6-7 service hours per day (more than a full tank of fuel).

Thanks.

imograss
03-03-2007, 04:35 PM
I have experienced those same issues. I bought 2 10323 series Lawnboys with the Duraforce. I never used them all that much. I got tired of messing with them. If anyone wants them for parts your welcome to them.Both have new coils, baggers, mulch plates. I replaced them with a Quick 36. Both are behind my shop. One ran somewhat and the other ran fine, and then the crank rope locked up. They have been sitting for 2 years. Anyone is welcome to them. I am an hour west of Nashville Tn. Pickup only.

lawnboy dan
03-03-2007, 06:22 PM
yes you can replace the entire carb. these carbs are tricky to work on and its eaiser to replace the whole thing

dutch1
03-04-2007, 08:45 AM
Two things I have experienced that you might check out:

1. Check for the governor vane hanging up in the opening where it encounters the air from the flywheel.

2. Check to see if you have overtightened the two screws that attach the carb to the block. I happened to discover this by accident on one of the first duraforces that I rebuilt a carb on. Overtightening can compress the plastic enough prevent the airvane/throttle shaft from being completely free.

In addition, check your governor spring and make sure the 90 degree bend is still sticking out of the slot of the governor vane/throttle shaft. If you accidentally overturned the governor control ring at the base of the vane, the bend can be pulled inside the ring, thereby losing governor control.

I'm not a LB fan but the duraforce was/is a decent engine. Nothing complicated about the carb to work on or adjust as long as you consider all aspects of its operation. The cork float is one feature that has always been a problem with LB. Sitting in fuel for long periods of time cause them to expand. thereby allowing the float to contact the carb body before the needle is able to shut off the fuel.

Dutch

lawnboy dan
03-04-2007, 10:02 AM
every lawn boy owner should install a fuel shut off valve because of the pos cork float. the older lawnboys with metal carbs have a metal float and never have carb problems. the plastic carb is a pos

dutch1
03-04-2007, 12:10 PM
LB Dan,

What LB model had a metal float? LB used a Walbro carb(similar to what you find on Briggs) on some models in the 70's-80's that used a plastic float. As far as reliability, I believe I have encountered more brass floats that were defective than plastic. Just last week I worked on a Tecumseh on a MTD snow blower that had set for a couple of years. Rebuilt the carb and the unit sat for 10 days. After a little snow the customer used it and after shutting if off, he called saying that fuel was running out of the bowl vent. Pulled it apart again and found a small pin hole where the float sat on the bottom of the carb bowl where moisture and varnish had aaccumulated. I've seen seam seal leaks in plastic carbs but never a pinhole. Brass floats are susceptible to both. I agree, the cork floats are crap.

Dutch

Roger
03-05-2007, 09:12 AM
Thanks guys for the insights. I will take these suggestions to the next work session. My working area is outside -- one day last week was acceptable, but nothing since and won't be for the next couple of days.

The idea of the bolt-up being too tight, thus distorting the carb is a good tip. I have checked the 90 degree tip extending through the hole in the knurled knob. I have had my share of "revelations" on this over the years -- getting all back together, only to discover the tip has become dislodged from the hole. That spring is so delicate, as contrasted with all the other work to get the carb fitted up right, getting the sliding disk through the slotted shaft, etc.

I will return to this project when the days get to be 40 again. At 35 my fingers get so cold, no feeling, and just cannot get all those little parts in the right place without feeling in the fingers.

Thanks.

lawnboy dan
03-05-2007, 09:40 AM
dutch-i stand corrected. walbro had plastic and not a metal float. too bad lawnboy returned to the pos plastic carb. the walbro was great and trouble free. and yes trying to fit that carb on a dura-force into place on a cold day isnt my idea of fun

Roger
03-25-2007, 08:04 PM
Update:

I spent more time working with the carb, throttle spring, and anything else I thought might be a problem. But, my efforts met with no success. I was very frustrated, nearly ready to take it to the junk pile.

In a desperation move, I ordered a carb assembly.

It arrived, but the weather didn't permit outside work for a few days. I was a bit surprised by the contents of the package. When the parts manual says "assembly," I presumed I would find a complete carb, ready for mounting. I had a fully assembled unit in mind, because I thought a new assembly would rule out any problems I may have inadvertently created with the old one.

Anyway, the package came with a bare, black plastic carb, a plastic bag of parts, and another smaller plastic bag inside the outside one, with even more parts, plus a small hard plastic box with a screw top containing the delicate parts (governor spring, choke spring, and a couple of other very small items). This was not a case of "some assembly required," rather "total assembly required." Nothing was put together.

I pulled off the old one, laid it beside me on the workbench, and had a good hard copy of the carb assembly from the parts book (downloaded from Toro web site). It all went together pretty easily. The most difficult part was the float valve and float spring.

After getting it all assembled, I mounted it on the DuraForce engine. After a bit of tinkering with the governor speed control knob, it works fine. The engine starts well, runs pretty well, and idles back to a proper speed. I say runs "pretty well," because I think it needs some run time at load to iron out the cobwebs a bit. I wish it ran just a bit smoother at full speed, but I am optimistic that after a couple of hours of service, it will be better.

I have ran it for awhile, let it sit, restarted. I have fired it a few times when cold, and it has started well. I don't know what else I can do for testing, so I will have to wait until I put it out on some properties for a full workout. I expect that to begin in about one week.

So, the question remains about the reasons for the old one not working the way it should. I am without answers.

Thanks for the help offered here. I wanted to report back. Maybe my experiences will help somebody else.

lawnboy dan
03-26-2007, 03:33 PM
well i would have been pretty pissed if i had paid for a whole carb assmbly and had to put it together! you can buy the whole thing as i have done so .like i said the plastic carb is a pos and very trouble prone . do your self a favor and install a fuel shut off valve and inline filter to minimise trouble caused by leaky needle/seat and dirt in the carb. some times a carb just cant be fixed and you just have to replace it. good luck

Roger
04-09-2007, 09:00 PM
Update ...

OK, the machine has been in working service for a week now. I have put through about 5 gallons of mixed fuel, so perhaps 30-34 hours of work.

It starts very well, and has good power. But, it surges nearly all the time. It is fine after cold starting, but after about two minutes, it starts. When the engine gets hot, then the surging is never ending.

I would say the period is about three seconds. The range is hard to know, but is more noticeable in sound than in speed, at least ground speed. It is SP, and the change in ground speed is hardly noticed.

I have changed the governor speed control, slowing it down. That change makes no difference. I have taken out the carb jet that screws in from the side (original had a sticker across the opening). The jet does not appear to have any debris.

I have not taken off the bowl, checking the screen. I am doubtful that I would find anything there, because the old carb had been used for a few months, and the screen was clean when I took it off. I inserted a fuel filter in the supply line from the tank a couple of years ago.

When I first started using the machine (after the carb build), it ran pretty well (refer to my previous post). The engine ran pretty well the first tank of fuel, or thereabouts. But, it started this surging behavior, and remains consistent from job to job.

I am more than concerned about the problem. Oh yes, it starts well, has good power, etc. And, I can barely tolerate the erratic engine speed. However, this is exactly the characteristic of the engine on this mower when it was new three years ago. I bought it in April 2003, and by August the engine was toast. The needle bearings on the crankshaft failed. And, that engine exhibited the same surging characteristic, one that the service tech never resolved. Far be it for me to suggest that the surging problem, and a very short engine life, are related. However, I've already "been there, done that," with a DuraForce engine.

Should I live with the surging, and put more cotton in my ears to block out the ill-sounding engine? Or, does anybody have a suggestion to attempt to remedy the problem?

dutch1
04-09-2007, 10:32 PM
Roger,

I wasn't aware that you put a new crank and needle bearings in the DuraForce. Did you do the repair or was it done at a dealer? Needle bearing failure that soon is very suspicious. When the crank was replaced, did you install new upper and lower seals? What was the case halves sealed with? Locktite 515, an anerobic sealant, is what is recommended. I'm beginning to suspect an air leak, either seals or case halves. Do you notice any accumulated oil/dirt at the case half joint or around the seals? With the engine running at recommended speed(3000 to 3200), spray down the case half seams and around carb where it joins the block and notice if the rpm changes noticeably.

In addition you may want to check the governor vane to make sure it is not catching on anything where it enters the blower housing. When you move the governor vane, does it snap back properly?

I'll do some additional thinking and if I come up with anything, I'll PM you.

Dutch

Roger
04-10-2007, 08:30 AM
Dutch - When the needle bearings failed, I repaired with an entire short block. This means it came to me sealed, reading for install. The present engine has run long hours with the short block, without the surging problem. Therefore, I am sure the surging problem didn't come with the short block. Now, maybe the original one that came with the mower had a problem with air leak -- something that was never checked.

However, your comments make me wonder if another check on the gasket between the carb and engine should be checked. If that gasket is leaking air, what would be the influence? Clearly, that gasket is one that was put in place when I bolted up the new carb.

I am quite sure the air vane/fin on the throttle control is free from obstruction. I have moved it freely many times. And, when the engine is surging, I see it rotate according to the surging pattern.

The operating conditions the past few days have been tough. Since last Tuesday, every day has been between 29 and 35, so the air temps have been cold. However, I don't think external temps should have an influence on the running condition of the engine. They have had influence on the operator, however!

Thanks for the input.

Roger
04-22-2007, 09:19 PM
Update ...

We have been running the LB hard for the past couple of weeks. The temps have been cold, until mid-week. I can only work outside, so kept on living with the surging the past couple of weeks. It is frustrating, knowing that something, probably minor is wrong. But, hoping that the fuel mixture inside the crankcase was not weak, we ran it every day, nearly all day. The schedule has been full, the phone ringing for more business, so I just kept working.

However, this afternoon, I HAD to take action. Oh yes, finally an 80 degree day, the first in a very long time.

My first action was to remove the new carb and disassemble, clean, looking for anything unusual. I did that, taking it down to bare bones (float and float jet out, main jet out, secondary jet out, ... nothing left to disassemble. All looked proper. I looked for anything that might suggest air leak, but found none.

I remounted the carb, and tried the mower. The problem remained. After it warmed a bit, the surging began just as it had been for the past couple of weeks.

I changed the spark plug. When I mounted the new carb a few weeks ago, I also changed plugs. I thought perhaps something was wrong with the seal on the plug, thus allowing an air leak. The new plug made no difference.

I took off the plate on the bottom, exposing the exhaust ports. Despite the walls being black, the primary hole was clear. My conclusion was to rule out an exhaust port problem.

Now, I'm at a total loss. I had visions of never finding a solution to this problem. As a next step, albeit a drastic one (I am desperate now!), I decided to mount the old carb. Nothing was broken when I took it off, and I saved it in the box when making the switch a few weeks ago.

After some very frustrating time, I finally get it mounted. Those gaskets, heat protector plate, air duct to the rear, ... all make for a very challenging time. I have done this procedure so many times, but it never seems to get any easier. All the tinkering gets very tedious, and wants to walk away. One time, I got it all together, then realized the hook from the governor spring, to the slider, had become disengaged. That means take it off, make the connection, then start the remounting all over again.

Finally, I got it all together. It fired up, but running a bit slow. An adjustment to the throttle knob changed the speed. I needed a couple of cycles to get it where I wanted. I took it out for some work across the yard, and it ran well. I continued for another 30 minutes or so, just so it was fully warmed. No surging!!! Yea!!!

Therefore, the surging problem followed the carb. The problem is not an air leak on the block.

By now, five hours have passed, and I'm fed up with this machine. I fill it with fuel, grease it, (already put on sharp blade when I checked the exhaust ports), and parked it. It is ready for a full day of work tomorrow, and I intend to use it all day. I will be disappointed if it does not run well. If so, I could be in the market for a replacement. This machine has been a nightmare from the very beginning.

Of course, the question remains, "What is wrong with the new carb?" By these steps, I think I have narrowed the problem to the new carb, and eliminated the engine block. Am I right about this?

For those who have worked on these engines often, you can follow all the detail of my procedure. And, you may identify with some of my frustrations about getting all the gaskets right, the heat shield, the air duct, ... and all the rest. Does anybody know any tricks for making it easier? I have no doubt that I will be doing this again. Is there something that can be used to "glue" both gaskets to the heat shield, so that the three pieces can act as one unit? That would help immensely.

Indy452
04-23-2007, 12:21 AM
Roger, you could use a small amount of Anaerobic gasket maker on the surfaces to be bonded. Permatex sells it in small tubes and a thin layer will keep everything in place and won't get all wierd like the silicone based gasket makers.

I'm sorry you have had so much trouble with those Duraforce engines they could have been great but those carb issues are something else. I traded my last Duraforce powered mower for a Toro proline W/Suzuki. Best decision I ever made.

Good luck, Neal

Roger
04-23-2007, 05:46 AM
I'm sorry you have had so much trouble with those Duraforce engines they could have been great but those carb issues are something else. I traded my last Duraforce powered mower for a Toro proline W/Suzuki. Best decision I ever made.

Good luck, Neal

Thanks for the tip. I have a tube of Permatex, but was reluctant to use it, thinking the gaskets would be very difficult to remove when the time comes. I will look into the product you mention.

The above comment is interesting, because I have exactly the same mower sitting right beside the LB/DuraForce in my garage. When my former LB needed replacement a few years ago (transmission problem, worn out), I bought a Toro ProLine with a 5.5hp Suzuki. We used it for the last part of that season (nearly an entire year), and a few weeks into the next season. It was relegated to secondary use, when the LB/DuraForce was put into service. That was three years ago.

The Toro has been used very sporadically since. I think I went through one tank of fuel all season (this LB runs about 6 hours most days, more than one tank of fuel). Last season, when I needed a second hand mower, I took the old LB (pre-DuraForce engine) instead. This season, I haven't even put fuel in the Toro.

Why? The answer has multiple facets. First, it is so much heavier. It takes much more effort to handle than the LB. Second, and primary reason, it does not bag nearly as well. We use a side bagger on the LB, and it is far superior to the Toro. I even purchased a special hi-lift blade for the Toro, but it still does not hold a candle to the LB. The side bagger for the LB has smaller bags, but we use three or four bags. It is easy to grab three bags before going behind a house, fill them and carry them to the trailer, often all at the same time. The boxy nature of the Toro bag does not permit this. Thirdly, the quality of cut on the LB is much better than the Toro. We have used them side-by-side, and there is no comparison. Last Friday, we mowed a property next to another one where an LCO was using three Toro/Kaw mowers. They were new last season. The quality of their work was terrible by comparison, e.g. stringers.

I get frustrated because, as a piece of equipment, the Toro is so much better. Obviously, the engine is far better. The Suzuki has never required one minute of effort to keep running well, other than routine maintenance. The parts on the Toro are better, e.g. ground drive cable, wheels, height adjusters.

At the moment, if the LB/DuraForce goes up in smoke, I would probably buy a new LB offset-wheel design with a B&S engine. We would be hard pressed to take the Toro back out on the journey.


Does anybody know when LB Platinum commercial mower will be on the market?

Indy452
04-23-2007, 08:24 AM
Roger, I don't think Lawnboy sells a staggered wheel lawnmower anymore. Someone correct me if I'm wrong but I thought Toro phased them out.

As for the Platinum comm mower, I'll guess it would be a high dome cast deck with rear discharge much like the newer Toro's. I think they come out this ear or next.

Neal

dutch1
04-23-2007, 11:01 PM
I think the day of the staggered wheel and 2 cycle engines is over or will be over very soon. About the only thing I see in the dealership I spent 6+ years in are conventional wheeled and are Honda or Tecumseh equipped. EPA regs are having an effect on the 2 strokers--notice the gradual change to 4 stroke technology in the hand held lines.

Roger, it's good to hear that you have had some success in getting the Dura-Farce working for you. Once in a while you have to walk in the horse muffins to get to the candy. I'd sure like to examine the new carb you had a bad experience with.

Dutch

Roger
04-25-2007, 10:10 AM
Update ...

After two days of running (Mon/Tue, about 2 gallons of mixed fuel, 11 hours of service time), the engine, with the old carb, runs very well. It may start a bit harder than with the new carb. However, it runs smooth and sounds great.

I think I can confirm the problem followed the carb. However, now I wonder why the old one created some headaches last Fall. Somehow the process of removal, then remounting (after sitting on the workbench for a few weeks) has made it work well.

Perhaps I should point to my own mechanical skills as the source of problem. For now, I am settled with the present arrangement, with the new carb sitting on the workbench. But, based upon past history, something will change in the near future.

Roger
05-17-2007, 10:33 PM
Update ...

The news is mixed. The machine has been run hard the past few weeks. For the most part, it has done well.

However, on a few occasions, it has reverted to a very hard warm-start. The last few days, the problem has not surfaced. Last week, one day, on two occasions, it would not start after sitting about 10 minutes. I think it required close to 50 pulls to get it started. On another time, only after I removed the spark plug and cleaned it, it would start. However, the pattern is not consistent, only intermittent.

I am wondering if I am mission a part on the upper part of the air box. The slider is fastened along the top surface. However, the entire slider assembly does not seem very stable. I am wondering if a rod, bracket, or some other device should be in place to hold that assembly tighter to the air box. I may have lost something.

The reason this question arises is the close fit between the forward portion of the slider assembly that engages the throttle spring, and the underside of the adjustment knob on the throttle fin. Sometimes I think they interfere. My concern is that the slider assemble gets a bit askew, and lever (where the spring engages) interferes with a free motion of the fin.

Late this afternoon (while on rain delay) I took a couple of pictures. I will try to insert them here.

The first one is from the rear, right under the fuel tank support. Note the upright protrusion that looks like it should have a wire through it.

The second image is from the left front, looking back to the carb/airbox.

I know they are very hard to see, and will only have meaning for those who know the layout very well.

Thanks for any observations from the pics.

dutch1
05-17-2007, 11:38 PM
Roger,
It would appear that you aren't missing anything. The throttle/choke slider is guided by the long solid wire and typically that wire can come out of one of the two bosses on either end leading to instability of the slider. The end of the guide shown(in the second picture) appears to be in the boss but I cannot see the far end. When this occurs I have cleaned the bosses and filled them with epoxy or super glue then reinsert the guide making sure the slider is free to move along the guide and that the washers on either end of the choke return spring are present. You can look up your model number on www.lawnboy.com for any missing parts and orientation if you still have a concern.

Your starting problem after the mower has been hot could possibly be a CDI ignition coil going bad(a common LB problem). If you have an inline spark checker, have it handy to check spark in those conditions. If no spark is present, remove the kill lead on the lower right hand side where the zone cable comes down to the engine and check again. If there is still no spark then it is most certainly a CDI problem. If you have spark with the kill lead disconnected more than likely you have a kill wire that is grounding out or a poorly adjusted kill lever.

Dutch

Bill Kapaun
05-18-2007, 02:07 AM
Roger-
I'm totally new to this thread and to be honest, I haven't read every post.
What I read seems like a lean surge condition.
I remembered this thread about rejetting Dura Force carbs from another forum.
I don't know if it's the same engine or even appropriate to jump in, but here's the link-
Bill

http://forums2.gardenweb.com/forums/load/lmower/msg072233252156.html

Roger
05-18-2007, 07:08 AM
Bill,

Thanks for the link. It looks like some interesting information. However, I think I will pass on the tinkering until Winter when time-loss isn't critical. [However, failure to start is also time-loss!]

Dutch,

I realize the images are hard to see. The area is hard to get a good pic, unless the carb is removed. My parts book does not show detail of the slider assembly on the top area of the air box. From what I can determine, the slider assembly is included with the part for the "air box assembly." Therefore, I can learn nothing from the parts list, hence the interest in having somebody who knows them well to take a look. If I see another LCO with one working in my neighborhood, I may just stop to ask for a look.


One other item I failed to mention in the other post. I have a broken spring in the starter assembly, the spring that returns the dog back to a retracted position. The dog will protrude (engaging the cup on the end of the crankshaft) when the rope is pulled, but when released the rotary spring will retract the dog. With the spring broken, the dog will fly out and rub a bit on the cup. It is not disabling, but needs to be fixed.

This is another case where the spring is not broken down as a part number level. There are a couple of parts (e.g. pulley, rope, ...), but then a "dog kit" part number. After calls to several dealers, I learned the dog kit was not an easy thing to find. I called an online parts supplier and they had one, which arrived in a couple of days. Yesterday, just after the package arrived, and during rain delay, I pulled off the starter. I found the kit included several items, but no rotary springs. After a couple of calls, we concluded the kit had missing items, namely the two rotary springs. It did have seven other items (center screw, two washers, compression spring, plate holding the dogs down, and the two dogs).

I share all this for reference to others who might read this. The "dog kit" should have nine items, replacing all the parts associated with the two dogs.

Wow, ... is there an end?

cccmachine
05-26-2007, 09:25 AM
enlarge those jets

chewy78
06-10-2010, 03:21 PM
I realize this is an old thread but I have a similar lawn boy 10323, and whats the trick to installing a new throttle/governor spring with out wrecking it?

Roger
06-11-2010, 06:59 AM
Yes, it is a challenge, isn't it? I've "been there, done that," far too many times!

I can't say that I ever found a fail-safe way. Every time seemed to be a different way. And, now, after not having done one in a couple of years, I can't begin to tell you how. I do recall that after doing the procedure a number of times each year when I was maintaining my machine, I did get better! I know, I know, ... doesn't help you.

The most I can help is that I would get it mounted "loose." I mean not trying to get it into the right torsional position upon installation. After getting it in place, then use the thumb wheel to tighten into a final position for proper speed. One problem with the "loose" procedure is that the hook end of the spring will easily come out from it's connection. So, it is a balance, loose enough to get into position, but not too loose as to loose the hook connection.

Sorry not to be of more help. You post brings back memories, none of them positive. My machine has been parked for two seasons now, replaced with a Honda. In two years, I've not touched the carb! I cannot believe I spent so much time trying to keep that Dura-Force running. I knew it was a hassle at the time, but in hindsight, I spent more time than I thought.

chewy78
06-11-2010, 09:57 AM
I figured it out a little, i took the carburetor completely off and i fed the other end through the slot in the air vane adjustment collar. I just looked at a parts list and i could also take the air vane out if i remove the butterfly valve out. now it runs tip top again. If it comes out of the slot again I will know what to do. otherwise it runs fine with no visible smoke which means that the short block seams to be in good shape.

You know I bought this used a couple of days ago and it came with a bag too. I just ordered a wire bracket for it. I got it because I like 2-cycles, i wanted a bagger and also a side discharge too. I do have a 20042 toro personal pace that a relative gave me in case this lawn boy craps out. the toro only mulched and nothing else.

Roger
06-11-2010, 09:58 PM
chewy78, ... glad to hear you got it running. I seem to recall the disk that makes up the butterfly valve (that passes through the slot in the plastic shaft) has a "up" side and a "down" side. I think it has a very small flat spot on one side. But, sorry, I can't recall if the spot is up or down. I do recall that if installed wrong side up, the butterfly will not rotate freely.

A major problem I had with the plastic carb on these machines is that the blind hole at the bottom (the plastic shaft pivots in this blind hole) becomes ovalized with use. This makes the shaft fit loosely in the prescribed envelope of space. There is no repair when the hole gets ovalized, or the stub end of the shaft goes out of round. Replacement is the only solution.

It doesn't take too many hours for his carb to "wear out" in these respects. This is considered one of the major downfalls of this machine: Plastic carb, and associated parts.

lawnboy dan
06-12-2010, 06:27 PM
these mowers were never desighned to hold up to real comm duty but will mow grass that nothing else can tackle

chewy78
06-28-2010, 05:07 AM
i found out that if you use a couple of drops of polyurethane glue such as gorilla glue on the throttle spring, the spring stays put and does not come out of the the hole in the throttle vane.

z3marlin
09-12-2014, 02:28 PM
new 2 stroke float weighs 5 gm. or slightly less. old sinking fuel logged float measured 9 gm.