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bsbretly
09-16-2009, 12:36 AM
I have a BS 135202 with a pulsa jet tank mounted carb on my go-kart. The engine was "surging" or "hunting" at full throttle. I would be at full throttle and it felt as the throttle was temporarily released (which it wasn't) then it would immediately retain full power. This process would repeat intermittently. I disassembled the entire carb and soaked it for 30min in chem-dip carb cleaner, hit all the jets with compressed air, and got rid of all visible dirt. I reinstalled the carb with new gaskets and the problem persists. Any ideas? I thought it could be fixed with adjustment of the idle mixture screw, but that didn't seem to help. Please let me know what the issue could be. Thank you.

Merkava_4
09-16-2009, 02:39 AM
Is this your carburetor?

http://www.partsandservice.com/db/pl/Briggs/135232.04.gif

bsbretly
09-16-2009, 01:41 PM
Yes that is it.

bsbretly
09-16-2009, 01:49 PM
I used that very same diagram in order to disassemble the carb

Merkava_4
09-16-2009, 11:42 PM
That's the same carburetor I have on my 3.5HP Briggs horizontal shaft. 127 and 127A are welsh plugs. It's probably not critical to pull the big one off the back, but the small one--> 127A should probably be pulled. I had the same problem that you're experiencing, and the mower shop owner told me to pull both those welsh plugs off and clean the holes behind them with a set of torch tip cleaners. Best advice I've ever gotten from a mower shop and it worked!! Well, only the small welsh plug has two small holes behind it and that's the one you want to pull. You can replace both of them if you want to - they're only a couple of dollars.

Those welch plugs are dome shaped to make them springy. When you install them by punching the center of them with a large center punch, right smack in the middle of them, they spread out and grab the recess permanently. Use a large center punch that's not too sharp so you don't punch through it.

If the big plug in the back is sucking air in around the rim of it, you can seal it up with clear finger nail enamel. Mine wasn't sucking air at 127, but 127A had one of the holes behind it block with corrosion.

If I remember correctly, behind the welsh plug is a brass jet with a large hole in it -- remove that jet by unthreading it with a screwdriver and you'll see the 2 small holes behind it that I'm talking about.

Merkava_4
09-17-2009, 12:08 AM
By the way, if the wire doesn't enter the hole fairly easily, select a smaller wire. You don't want to enlarge the hole, just remove the white deposits blocking the flow of fuel through it.

bsbretly
09-17-2009, 12:40 AM
I see, thanks. Do you have to pull the entire carb back off or can you get out the welsh plug while the carb is still bolted to the tank?

Restrorob
09-17-2009, 12:43 AM
By the way, if the wire doesn't enter the hole fairly easily, select a smaller wire. You don't want to enlarge the hole, just remove the white deposits blocking the flow of fuel through it.

Nice of you to add that ! Thumbs Up

BTW, There's no jet behind 127A.......

bsbretly
09-17-2009, 12:52 AM
So one of you is saying there are jets behind the small welsh plug (127a) and the other says there are no jets behind it. Which one is it? Also, how are these welsh plugs removed?

Merkava_4
09-17-2009, 02:11 AM
BTW, There's no jet behind 127A.......

Then what's behind it? Maybe I'm thinking of the other carb with the single pick up tube. I've been through so many carbs I've lost track. :confused:

Wait!! I think its coming back to me.... there's 2 holes that lead to a passageway to the diaphragm chamber, correct?

Restrorob
09-17-2009, 08:08 AM
there's 2 holes that lead to a passageway to the diaphragm chamber, correct?

Bingo..... This is the newer single pick-up tube carb, The older style had a long and short pick-up tube and had the adjuster screwed into a removable nut. Behind this nut was the main jet which when removed provided access to the ports behind it.


bsbretly,

To remove the welsh plug get a small sheet metal screw then carefully and slowly drill a hole in the center then turn the screw in only 1 or 2 turns, Grab the head of the screw with pliers and the plug should pull right out.

The carb doesn't have to come back off the tank to do this....

bsbretly
09-17-2009, 01:22 PM
Then what's behind it? Maybe I'm thinking of the other carb with the single pick up tube. I've been through so many carbs I've lost track. :confused:

Wait!! I think its coming back to me.... there's 2 holes that lead to a passageway to the diaphragm chamber, correct?

yes there are two holes in the diaphragm cover

bsbretly
09-17-2009, 01:24 PM
Bingo..... This is the newer single pick-up tube carb, The older style had a long and short pick-up tube and had the adjuster screwed into a removable nut. Behind this nut was the main jet which when removed provided access to the ports behind it.


bsbretly,

To remove the welsh plug get a small sheet metal screw then carefully and slowly drill a hole in the center then turn the screw in only 1 or 2 turns, Grab the head of the screw with pliers and the plug should pull right out.

The carb doesn't have to come back off the tank to do this....

Alright, but since there are no jets behind these plugs, is there any sense in removing them? Any other ideas on why my engine is still surging?

bsbretly
09-17-2009, 03:46 PM
Looking at a diagram of the linkages for my engine, I have notice that the bell crank is not connected to throttle (as I have the throttle connected to a throttle cable hooked up to the gokart pedal) so the bell crank it unhooked from the throttle and doesn't move during use of the engine. Is this a problem? Also could there be something wrong with my governor linkage? Switching the setting from idle to fast doesn't seem to change the performance of the engine. For the parts I'm refering to take a look at this link: http://www.small-engines.com/5briggs.html

Restrorob
09-17-2009, 09:46 PM
the bell crank it unhooked from the throttle and doesn't move during use of the engine. Is this a problem?


That very well could be the problem, If the bell crank is not hooked up the governor is not hooked up therefor you will never hold smooth full throttle operation.

You need to have all linkages and springs hooked up as shown in the picture link you posted with the exception of the one below;


http://i107.photobucket.com/albums/m314/Restrorob/Briggs/L%20Singles/Briggs135200UpperThrottleLink.jpg


On a go-cart application you can not have this link installed, If your's is already removed that's fine.

Once you have all other linkage and springs installed properly you can pick up this go-cart throttle control kit on-line or at any Briggs dealer;

http://i107.photobucket.com/albums/m314/Restrorob/Briggs/L%20Singles/Briggs135200ThrottleCableKit.jpg

http://www.briggsandstratton.com/maint_repair/repair_parts/index.aspx?_dp=1&pno=692316


Once you have this kit you can install your throttle cable down under the fuel tank as it should be;


http://i107.photobucket.com/albums/m314/Restrorob/Briggs/L%20Singles/Briggs135200ThrottleCableHook-up.jpg


With everything installed as outlined above, The throttle and governor should operate properly for a go-cart application and should give smooth high speed operation.

I would not fool with removal of the welsh plug as of yet until the throttle is functioning properly.....

Merkava_4
09-18-2009, 02:50 AM
yes there are two holes in the diaphragm cover

There's two holes behind that small welch plug too; and if one of the holes is plugged up with crap, you won't get enough fuel to the engine to operate throughout the whole rpm range.

bsbretly
09-18-2009, 12:46 PM
BTW, There's no jet behind 127A.......

I thought we concluded that there are no jets behind the small welsh plug...?

Restrorob
09-18-2009, 12:54 PM
We did !

There is no removable jet behind the welsh plug but there is two tiny ports, But as mentioned..... Get the throttle/governor working properly and you may not need to fool with the welsh plug.

Merkava_4
09-18-2009, 01:27 PM
There is no removable jet behind the welsh plug but there is two tiny ports,

AH HA!! I finally got you to admit to it!! :p

bsbretly
09-18-2009, 01:37 PM
We did !

There is no removable jet behind the welsh plug but there is two tiny ports, But as mentioned..... Get the throttle/governor working properly and you may not need to fool with the welsh plug.

I see, thanks. I'm going to take a picture of my current throttle set-up and post it here. The only reason I am skeptical about this solution is that I have had this same throttle set up for the past couple years and it has functioned fine until the recent surging.

bsbretly
09-18-2009, 03:38 PM
Here are the pictures of my throttle set-up:
http://i47.photobucket.com/albums/f181/bsbretly/gokart-top.jpg?t=1253298855
http://i47.photobucket.com/albums/f181/bsbretly/gokart-side.jpg?t=1253298925
From what I can tell, it looks like I'm not using the governor at all as the throttle is not connected to it in anyway. The strange thing is is that I have used this setup for over a year (the go kart is used very rarely and only for small time intervals) and there was no surging until it was started up for the first time in several months. Let me know what you think, thanks.

Merkava_4
09-19-2009, 12:06 AM
From what I can tell, it looks like I'm not using the governor at all as the throttle is not connected to it in anyway.

They've got all kinds of ways to set up the governor control in the book, but none of the examples show the remote throttle cable going directly to the throttle valve like you're doing; they all show the air-vane link going to the throttle valve, and then the remote throttle cable going to the slide control.

Mine is set up the correct way for my application, but I don't know if the way mine is set up would work for your go-cart. I could take pictures of my governor set-up, but I don't know if it would do you any good.

Restrorob
09-19-2009, 12:09 AM
Hmmm.....

If I remember correctly, behind the welsh plug is a brass jet with a large hole in it -- remove that jet by unthreading it with a screwdriver and you'll see the 2 small holes behind it that I'm talking about.


BTW, There's no jet behind 127A.......



there's 2 holes that lead to a passageway to the diaphragm chamber, correct?

Technically these two ports lead to the air intake venturi not the diaphragm chamber......

Bingo..... This is the newer single pick-up tube carb, The older style had a long and short pick-up tube and had the adjuster screwed into a removable nut. Behind this nut was the main jet which when removed provided access to the ports behind it.



AH HA!! I finally got you to admit to it!!


Show me up there or anywhere that I said there was no ports behind this welsh plug or jet if it did have one !!! http://www.ostfriesenpower.org/neues.htm/e124.gif



bsbretly,

You can run the throttle any way you like, Take the plug out and clean the ports and hope that solves your problem.

Working in a shop I MUST repair properly for liability reasons especially when kids are involved.

Good Luck Thumbs Up

Merkava_4
09-19-2009, 12:23 AM
You can run the throttle any way you like, Take the plug out and clean the ports and hope that solves your problem.


Are you saying it's OK to bypass the air-vane governor?

I'm thinking if you have the remote throttle cable going directly to the throttle valve, you're gonna get a huge rush of air in there before the fuel has a chance to get to it first -- that's the whole purpose of the air vane governor I thought, was to keep the air from rushing into the carb until there was enough fuel there.

Your thoughts?

bsbretly
09-19-2009, 01:52 AM
Take the plug out and clean the ports and hope that solves your problem.
You're refering to the small welsh plug or "port" right, not the large one on the back? Also if I drill that small welsh out without taking off the carb won't a whole bunch of metal scraps go into the otherwise clean carb?

bsbretly
09-19-2009, 01:53 AM
They've got all kinds of ways to set up the governor control in the book, but none of the examples show the remote throttle cable going directly to the throttle valve like you're doing; they all show the air-vane link going to the throttle valve, and then the remote throttle cable going to the slide control.

Mine is set up the correct way for my application, but I don't know if the way mine is set up would work for your go-cart. I could take pictures of my governor set-up, but I don't know if it would do you any good.

What is the air-vane link?

bsbretly
09-19-2009, 01:59 AM
bsbretly,

You can run the throttle any way you like, Take the plug out and clean the ports and hope that solves your problem.

Working in a shop I MUST repair properly for liability reasons especially when kids are involved.

Good Luck Thumbs Up

Sorry for the confusion, but I thought you said I needed to buy that throttle kit you referred to several posts ago to properly utilize the governor and other linkages, otherwise the engine would not run properly? My current set-up bypasses all these linkages.

Merkava_4
09-19-2009, 03:14 AM
You're refering to the small welsh plug or "port" right, not the large one on the back? Also if I drill that small welsh out without taking off the carb won't a whole bunch of metal scraps go into the otherwise clean carb?

Behind the small welsh plug is the two small ports. If you do drill a hole, don't put too much pressure on the drill because the ports are not too far behind that welch plug; go easy and take your time. After you drill the hole, you can either pry the plug off with a small screwdriver, or you can thread a sheet metal screw into the plug and pull it out with pliers.

What is the air-vane link?

The air-vane is under the starter cover. It'll be attached to the electronic coil. The link hooks on that air-vane on one end and then the other end hooks to the throttle valve. They'll be a curly Q in the link; that's where the spring hooks to. The other end of the spring hooks onto the slide control.

Restrorob
09-19-2009, 08:34 AM
Are you saying it's OK to bypass the air-vane governor?

I'm thinking if you have the remote throttle cable going directly to the throttle valve, you're gonna get a huge rush of air in there before the fuel has a chance to get to it first -- that's the whole purpose of the air vane governor I thought, was to keep the air from rushing into the carb until there was enough fuel there.

Your thoughts?

Sorry for the confusion, but I thought you said I needed to buy that throttle kit you referred to several posts ago to properly utilize the governor and other linkages, otherwise the engine would not run properly? My current set-up bypasses all these linkages.



OK, From the top and to remove confusion.....


Merkava_4,

It's never OK to bypass ANY style governor system

You sir are comparing a 3.5 hp engine with a 5 hp engine, They are different.

Your 3.5 does have a air vain governor, This air vein has nothing to do with air entering the carb throat other than opening the throttle butterfly when more load is applied to the engine. It doesn't direct air into the carb.

The 5 hp in question has a mechanical flyweight governor gear inside the crankcase that's operated off the camshaft gear.


bsbretly,

My reasoning behind hooking the throttle up correctly with the governor functional is this;

People that race go-carts remove the governor from the engine and hook the throttle up like yours, They do this to gain more rpm's for more speed but it kills the engine's life. They race on smooth race tracks where they keep the pedal buried to the floor. On a typical yard cart running down bumpy roads/across yards it's harder to keep the pedal buried to the floor, So your foot bounces around on the pedal thus causing the a high speed surge because the governor is bypassed making the throttle too sensitive.

I said this;

You can run the throttle any way you like

Because you said you were skeptical that was your problem.....

Could it be ? I don't know, But I do know this engine in a yard cart application should have the governor and throttle controls hooked up properly to prevent the above mentioned from happening and prolong the life of the engine.

bsbretly
09-19-2009, 04:04 PM
Alright, thank you both for helping me out. The plug will have to replaced after and should I just blow out the holes behind the welsh plug with compressed air? Thanks.

bsbretly
09-19-2009, 11:27 PM
Sorry, what I meant to ask is how is the plug replaced after removal? Also how should I clean out the holes? Is compressed air sufficient?

Merkava_4
09-20-2009, 01:12 AM
In my opinion, compressed air is not sufficient to remove aluminum corrosion; tip cleaners is what I recommend. You install the new welch plug with a large center punch; or one that's not too sharp. It should leave a slight dimple in the middle of the plug.

bsbretly
09-20-2009, 09:55 PM
In my opinion, compressed air is not sufficient to remove aluminum corrosion; tip cleaners is what I recommend. You install the new welch plug with a large center punch; or one that's not too sharp. It should leave a slight dimple in the middle of the plug.

Alright great, thank you. I'm not sure what a "tip cleaner" is, where can you buy one and what is it? Is it like a tiny bottle brush?

Restrorob
09-20-2009, 10:15 PM
There's no need in buying a tip cleaner for two holes, Use a bristle cut from a hand wire brush and hold it in a pair of pliers.....

bsbretly
09-20-2009, 11:07 PM
There's no need in buying a tip cleaner for two holes, Use a bristle cut from a hand wire brush and hold it in a pair of pliers.....

Alright, so just pull one of the wires off of a wire brush and use that with some pliers? Also, someone else recomended simply using the metal wire in the tie-offs they use on bread and other stuff. Would either work?

Merkava_4
09-21-2009, 04:29 AM
I'm not sure what a "tip cleaner" is,

Click on this link:
http://www.csuchicoag.org/AgMech/ImagePages/images/TipCleaner.jpg

It would be the best $5.00 you ever spent.

Restrorob
09-21-2009, 10:05 AM
Alright, so just pull one of the wires off of a wire brush and use that with some pliers? That's what I said.Also, someone else recomended simply using the metal wire in the tie-offs they use on bread and other stuff. Would either work?

Any small wire will work to clean two small holes, Take the five bux and buy a couple soda pops..... :)

bsbretly
12-19-2009, 09:26 PM
Just wanted to post an update: I replaced the welsh plug and cleaned out the jets behind it and I the engin runs a lot more smoothly. Thanks for all the help. I might replace the larger welsh plug on the back of the carb as well too.

koocuz
04-18-2010, 12:19 AM
Hi Folks,

I have a Briggs 5HP engine with the Pulsa-Jet carb, its about 8 years old and i just took apart the carp and cleaned it as well as replaced the diaphram (probably not even needed) and the gasket between the tank and carb. Anyways at first it would not start at all, but after shooting carb cleaner through it (through the second fuel pickup area) it runs!

Now for the fun part, I am pretty sure I put it all back together right but at low speeds it surges like crazy, at full throttle it is not too bad but you can see the governor still moving back and forth a little.

I tried to adjust the fuel mixture screw and it did nothing at all.... All the way screwed in and completely removed the engine seems to run the same..

Do you think removing the small plug and checking those two jet might help or is this problem somewhere else?

Thanks!

Restrorob
04-18-2010, 09:20 AM
Do you think removing the small plug and checking those two jet might help

That would be the next step.....