Motor Revs Up and Down At Idle.

[Cosbro]

I am trying to revive my Manco Dingo. I put a motor on it a few years ago because the old one blew. I cleand and lubed the torque converter the other day. When at idle, it (revs?) up and down. It engages the clutch when the rpm is at the highest during idle. The engine then stalls when the idle drops.

Any help is appreciated.

 

[J.S.@SMS]

It sounds like its the carburetor. A few pics of the engine and carburetor would be nice as some engines have more carburetor trouble than others.

 

[Cosbro]

OK. I will get pics when I can (tonight). It will look like crap, but I'm working on it.

 

[numscul]

it sounds like you have a TECUMSEH 6.0HP with bad governor surge.. am i correct ?

If you do here is an easy fix

Remove the engine and place it in the garbage <--(just my opinion)

I am going to assume its a TECUMSEH because this is a common issue with them......
And i hate them more than the smell of burnt hair

This fix here can be applied to most upright engines with similar mechanics

If the governor surges up and down, then the problem may be a plugged carburetor, a plugged idle circuit or a worn linkage.
If you check these components and see that they work properly, then the set of the governor may be too sensitive.
This means that it reacts too quickly and overcompensates for the speed.

Move the spring to a hole in the governor arm that is farther from the shaft to decrease sensitivity.

Check the linkage and spring of the governor to ensure that they operate freely and are not stretched or damaged.

Check that all free play is removed from between the carburetor and spindle of the governor's static adjustment. You can check this when you move the air throttle to full open from idle to see how the governor shaft moves.
If the governor shaft moves clockwise, then loosen the clamp screw and turn the shaft clockwise. Replace the clamp screw and check the engine to ensure that the air throttle moves freely from idle to full open.



let us know if that helps if not we can move to the other probable causes and eliminate them one by one till it's better

 

[landuse]

Cleaning the carb would be the first thing to try

 

[Karttekk]

Disassemble the carb then soak it overnight in one of these. The next day remove the carb from the basket, rinse it under water then blow it out with compressed air if possible. Reassemble it hopefully with a new gasket kit if you can find one. Sometimes they get so clogged replacement is the only option. Guess cheap first.

Thanks

 

[Joe-405]

Put it up on blocks and put some sea foam in the gas tank and let it run for about 15 minutes. And say like a half a cup not more than that.

When I work at the lawnmower shop we do that first if we think it’s a carb issue. If it works you’ll know before that 15-20 minute mark. You will physically here it change.