80 kitty cat doesn't idle - help

[johnniev57]

I've cleaned the carb a few times now. Now it seems to run great, but won't idle. just dies right off. if I brapp the throttle it will keep running. it will run for a while if I stay on the throttle, but soon as i let off it will die out......

argh

which jet does the idle? I can try to make sure it's clean again.
or do I need to replace motor seals

Thanks for any help!!!

[ziggster]

A snowmobile carburetor that won't idle could be due to various issues, and clogged jets are indeed one of the potential causes. Here are some steps you can take to troubleshoot the problem:

1. Check the Fuel: Ensure that you have fresh, clean fuel in the snowmobile's fuel tank. Stale or contaminated fuel can lead to carburetor issues. Drain any old fuel and replace it with fresh gasoline.
2. Inspect the Air Filter: A dirty or clogged air filter can affect the air-to-fuel ratio and cause problems with idling. Remove the air filter and clean or replace it if necessary.
3. Clean the Carburetor: If you suspect the jets are clogged, it may be necessary to clean the carburetor. Start by removing the carburetor from the snowmobile according to the manufacturer's instructions. Carefully disassemble the carburetor, taking note of the jet locations.
4. Clean the Jets: Use a carburetor cleaner and a small, soft brush to clean the jets. Pay particular attention to the idle circuit jets, as these are most likely to cause idling issues. Ensure that all passages and orifices are clear of any debris or residue.
5. Reassemble and Adjust: Once the jets and carburetor are clean, reassemble them in the reverse order of disassembly. Make sure all connections and seals are secure. Refer to the snowmobile's manual for any specific adjustment procedures, such as idle speed or mixture adjustments.
6. Test and Fine-tune: Start the snowmobile and allow it to warm up. Test the idling performance, making note of any improvements or continued issues. Fine-tune the carburetor adjustments if needed, following the manufacturer's recommendations.

If cleaning the carburetor and jets does not resolve the idling issue, it's possible that there may be other underlying problems such as fuel delivery issues, ignition system problems, or mechanical issues. So you may need to look elsewhere.

[stephen79]

I think the most common problem is that the carburetor mixes air and fuel for the engine and over time, it gets clogged with dirt, debris, or old fuel, which disrupts the proper air-fuel mixture.

I would always start by cleaning the carburetor thoroughly using a carburetor cleaner. Pay special attention to the jets and passages. In some cases, a rebuild kit may be necessary to replace worn parts. Cleaning is easy and it fixes most idle problems.

[stephen79]

I should actually mention that the idle air-fuel mixture may be too rich (meaning too much fuel) or too lean (meaning too much air), causing poor idling. Either extreme will cause idle problems.

You would have to adjust the air-fuel mixture screw on the carburetor to achieve the correct balance. If you have one, refer to the service manual for the proper adjustment procedure. I don't have it handy, but you would just follow the steps.

[yland70]

Also watch the choke closely. A stuck or improperly functioning choke can cause the engine to run too rich, leading to idling problems. I think the choke gets overlooked. Just check the choke mechanism to ensure it operates smoothly and is not sticking or stuck one way or another.

Another thing you can try is to spray carburetor cleaner around the intake manifold and carburetor gaskets while the engine is running. If the engine idle changes, you may have found a vacuum leak. It's another old-school snowmobile carburetor trick.