Stalling while coming to a stop
- Thread starter Lee Mitch
- Start date
pat in Santa Cruz
Well-known member
Among the myriad causes of this common condition, see poorly adjusted float, clogged idle jet. This condition is also associated with a vacuum leak. Aside from the obvious leaks in the vacuum system (tubing, fittings, windshield wiper) check manifold and carburetor gaskets. Check to see if the carburetor flange is flat, not warped. Check to see if your throttle shaft is loose in the carburetor body. That is often overlooked, and it certainly will cause it.
try this site for diagnosing it:
http://modela.org/engine_dies_stop.html
try this site for diagnosing it:
http://modela.org/engine_dies_stop.html
Purdy Swoft
Well-known member
Usually it will be incorrect float level. Being as the GAV has an effect it could well be a problem with the idle jet as Pat mentions above in post #3. Richening the GAV could compensate for a lean condition caused by a blocked idle jet.
fiddlybits
Senior Member
I had the same problem and had overhauled the carb and repeatedly checked the specs, especially the float. It would leak fuel and slow/stall during braking.
Finally had my fill so I clamped a rod in the vise, taped a ball jar to it, plopped the top half of the carb on top of the jar and used a clamp to secure it. Added a fuel hose that feeds from a small container and I was all set to SEE the actual fuel level.
Found out 2 things.
1. The fuel level was LOW, which was actually the reason for the slower idle and occasional stall when stopping. A thinner gasket fixed the level.
2. The float valve was not leaking but the valve gasket was leaking. In other words, the valve was closing properly but fuel was seeping by the threads and gasket. A little formagasket #2 and the carb functions
Finally had my fill so I clamped a rod in the vise, taped a ball jar to it, plopped the top half of the carb on top of the jar and used a clamp to secure it. Added a fuel hose that feeds from a small container and I was all set to SEE the actual fuel level.
Found out 2 things.
1. The fuel level was LOW, which was actually the reason for the slower idle and occasional stall when stopping. A thinner gasket fixed the level.
2. The float valve was not leaking but the valve gasket was leaking. In other words, the valve was closing properly but fuel was seeping by the threads and gasket. A little formagasket #2 and the carb functions
glenn in camino
Well-known member
You have an air leak. Most likely your throttle shaft. The fix is bushings in the upper part of the carburetor where the throttle shaft goes through. Most suppliers sell the bushings or go to a hobby shop and get some brass tubing in the right size.
700rpm
Well-known member
Lee, make sure your float is at the correct level and that your main and cap jets are at the same height in the throat, and their tips are above the fuel level in the bowl. Dave Adair has the jet flow tester, and you could use that to check all your jets. There's a good booklet with that to show you how it all relates.
Mike V. Florida
Well-known member
They also sell a fuel level gauge that mounts to the bottom of the carb to see the actual level of the fuel.
Or
fiddlybits
Senior Member
They also sell a fuel level gauge that mounts to the bottom of the carb to see the actual level of the fuel.
Or
Hey, that's pretty cool and would have been a simpler solution for item 1, the actual fuel level. It also would allow a check with the carb still on the engine.
I guess I'm glad I did not know about it and used the clear glass ball jar as it allowed me to see what was going on inside and see that the fuel was leaking in "above" the float valve.
I think I might put one together for my troubleshooting box.
(I see someone comes from the same school of "so simple it is genius" as I did...using a stiff wire inside a flexible host to keep the hose where you want it. I always use stainless safety wire.)
