Throttle Lever to Screw stalls engine?

JoeRagMan

LawnSite Senior Member
Location
Near TMI
Sounds like you’ve done your homework, I sorry you don’t live near me as that my time spent with neighbors. “Junk won’t go? Call Joe!”
Anyway, I use carburetor cleaner followed by compressed air. I do not know if canned air has enough pressure. I have a small pancake compressor, 120 psi, maybe but it was more than enough.
If you have the manuals, you should be able to check the governor adjustment. Also check the location of the carburetor springs/governor rod linkage. If they are placed in the wrong holes, it will cause many problems. Sounds like the mower has been maintained (ouch on the cost!) so might be something simple. I would take a couple of pictures of the carburetor linkage and compare them to the manual. If they appear to be correct, then pull the carburetor off again? Hope this helps, keep us posted as I like to hear success stories!
 
OP
SnapperOwner

SnapperOwner

LawnSite Member
Location
Ohio
Okay, we'll try cleaning the carb again. Is there any better way to remove it than sitting there unscrewing it from the fuel solenoid in the back while the gas is flying all over the place?

Sorry to have misled about the maintaining. Unfortunately, the reason I "inherited" this mess a month ago is because I discovered that it was not being serviced other than to fix small problems involving changing parts out. And it was filthy when I started on this.

We've taken photos of the linkage and compared them to the book, and I think it looks all right. It's the throttle and choke cables, though, that are raising flags for me. The person who adjusted those did not know what they were doing. I've looked all over, but sites only say "reconnect the cable and move on". Fine and dandy, as long as you know HOW to connect them in the first place (smile). Even the Service Manual doesn't say more than that. Can they be too loose or tight? If so, how do I know when they're just right?
 

JoeRagMan

LawnSite Senior Member
Location
Near TMI
Before removing the carburetor maybe try checking for leaks in the intake manifold. Engine running, take a propane torch, unlit of course, and run the propane around the intake manifold gaskets, etc. If the engine smoothed out, there is an air leak, air sucking through a bad gasket instead of going through the carburetor. You can use carburetor cleaner or some other flammable spray but use extreme caution! Have a fire extinguisher close by. If it doesn’t smooth out, then I guess the carburetor removal is next.
The other concern is that you mentioned the excessive debris on the flywheel. How bad were the cylinder fins and are they clean now? Also, depending how far you want to go, you could do a leak down test to see what condition the engine is in?
 
OP
SnapperOwner

SnapperOwner

LawnSite Member
Location
Ohio
Thanks, again, for sticking with me on this. You just got ahead of me, though. Don't have a propane torch, and you scared me off the carb-cleaner test with the fire extinguisher comment.

Those fins were pretty thatched, but they're great now. I'll look into a leak down test (probably don't have the equipment in my garage). Someone did come over and do a compression test, for all that's worth: 130 and 119. Don't have any idea if he knew what he was doing but have been told that the numbers are good (even within the 10%-of-each-other allowance).

I'm afraid that my mind works from simple and up. Thought if I could figure out how to stop it from stalling when we hold the throttle lever against the screw that other symptoms might develop that would show us something more. Of course, there's always the hope that carb adjustments would actually fix the thing. The engine was quite smooth 2+ weeks ago, before someone took the limiter caps off and started wildly and maniacally turning all three screws around like whirlygigs.

If it doesn't seem like I'm being too simple, do you have any ideas about why the engine would stall when I touch the lever to the screw?
 

JoeRagMan

LawnSite Senior Member
Location
Near TMI
Okay, sounds like the compression is good to go. Here are two websites to check out:
www.outdoor power info.com
the second site has Briggs and Stratton carburetors listed, hopefully one of them will be of some help.
As far as using a flammable spray or propane, those are ways of testing to see if there is a leak somewhere on the intake manifold. Just need to be careful, one spark from a bad plug wire you won’t have to worry about the carburetor, hard to fix a burnt mower.
Just need to be careful.
Think about using a plastic straw that has a crack, hard to pull the liquid into your mouth. Same theory with a leaking gasket, engine sucks too much air but not enough fuel.
 
OP
SnapperOwner

SnapperOwner

LawnSite Member
Location
Ohio
First of all, that is an amazing site -- Carb & Gas 101 for Dummies! That's ME! It has a lot of info that I've been looking for. That site has NEVER ONCE shown up on a Google search. Thanks!

First the carb issue, if you don't mind. I've been sitting here since my last post reading through the Service Manual. When I got to the carb section, I realized that it might not have been as cleaned out as I thought. I wasn't in on any of the three cleanings, because I was working on other things. But I know the guy that did it for me did not take all those parts out.

Also, your lawnmowerfixed guy says that the rubber tips on the needle valves turn pink when they're worn out. Well, I've been posting all over looking for info on the needle valve with the reddish-pink tip! Does everyone agree with him? The fact that I have this red/pink tip on my needle valve means that it's shot?

The other thing I noticed in the manual (and looking on eBay for Overhaul kits) is that there are several seals that should be replaced in the carb. Since I'm the one who does the parts buying around here, I know for a fact that no seals were replaced. And the old float bowl gasket inside the carb looked fine, so it went back in, too. The air-filter-mount-to-carb gasket was replaced but not the carb-to-intake behind it. That was probably a mistake, too. Just because it didn't crumble when it was taken off (like the other one did), it was assumed it was okay. Bad choice, methinks (smile).

So, after reading through the manual, I thought I'd take another look around online and see if my dealer was charging me top dollar at $270 to replace the whole carb. Holy cow! In four weeks, it's gone up from there and is nearer the $300 mark now! PLUS, the replacement is some EPA-friendly job with no idle mixture screws and a different solenoid than my model was engineered for. Thought I could cheat and find an old Parts list (pre-Dec 2009) that would give me the old part number. Found the number, I think, but any of those models that are still available are just earlier versions of the same thing they're selling now.

Between the money and lack of availability, I'm wondering if I should just bite the bullet and find a Briggs overhaul kit that I can afford. Reading through the Service Manual, I'm more than willing to try. (At least, it didn't scare me off like the fire extinguisher routine--big smile.) That leaves me with two questions for now:
1) Is the body of a carb (TK Nikki, according to the book) very often so warped that it's unusable? Is it worth my money and time to try?
2) I've seen brand-new Briggs OEM overhaul kits online; one Made in China, one Made in Japan. If I buy someone's old stock, is there a chance that the seals and gaskets will be old and unusable?

Now, if you've gotten this far and haven't abandoned ship, yet, I have one more question for you, Joe. Am I jumping the gun thinking about rebuilding the carb without doing a leak test on the manifold? This is a lot of money for me right now, so I'd hate to invest in something at the wrong time.

Again, thanks! You give me hope that my daughter might be able to hang up her weedeater before winter. Her back hurts by the time she hits that second acre . . .
 

JoeRagMan

LawnSite Senior Member
Location
Near TMI
Just want to tell you that I am not a professional small engine tech, like I said before, I’m the neighborhood troubleshooter because I’m the only one around that’s dumb enough to get my hands dirty. I am a retired building maintenance tech for a Corp. in Hershey,Pa. I was tasked with just about every system and most equipment, Hvac, electrical, plumbing, diesel and gasoline engines. Part of my job was to try to repair or decide who to call to repair/replace equipment. So all I can help you with is trying to first determine what the problem might be before spending money on parts that might not be needed. To that end, if you can get the engine to run smoothly so you can troubleshoot it easier, I will have accomplished what I am trying to do.
You mentioned in an earlier post the if you touched the carburetor linkage, the engine acted up? How about checking the choke butterfly when the engine is off, when you slide the throttle to choke, does the choke close? Does the throttle plate close as the throttle is decreased? Thinking like you, someone has the choke/ throttle/governor linkages messed up.
As far as the correct color of the carburetor float needle, never heard of that, most float needles I’ve messed with were metal. Don’t know if the float can be checked easily but if the engine oil isn’t over full and doesn’t smell like fuel, probably it’s okay.
 

HEMTT

LawnSite Bronze Member
Location
Snohomish, WA
A small compressor will provide all the pressure you need, you don't need much volume of air. Canned air isn't much higher pressure, less than 150 PSI but it is more handy for field repairs.
 

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