Quadrunner Dies When Hot

[Tazzer]

I have a 1991 Quadrunner with a new carb. Runs good when first starts. But after about 15 minutes thee idle will drop down and finally stall. Then I can't get it started until it cools off. Any ideas of what may be causing the problem?

[rpyfz450]

Once the engine is warm and stopped running, if you let it sit for another 15 minutes (not long enough to cool completely), will it demonstrate the same problem? If so, you may have a partially blocked fuel line, petcock, fuel filter, or tank breather. This problem would appear every 15 minutes regardless whether warm or cold, although the 15 minues may be reduced if you're using the choke to warm it up.

If it really is temperature related, it could possibly be electrical. As a very general statement, electronics prefer colder temperatures to warmr ones. Do you have a friend with asimilar machine that you could swap electrical parts with?

[Snafoow]

Check the valve lash. There my be no gap between the rocker arms and valve stems. These parts expand and get bigger when hot, and it may be enough to keep the valves from sealing on their seats as they heat up.

Also like Kirt said, Check for good spark when it wont start and make sure you have a good fuel supply at the carb. May be easiest to open the bowl drain on the bottom of the carb and turn the fuel on and see if it has a good flow.

[CycleProRacing]

<div class='quotetop'>QUOTE (Tazzer @ Dec 5 2005, 12:57 PM) <{POST_SNAPBACK}></div>

I have a 1991 Quadrunner with a new carb. Runs good when first starts. But after about 15 minutes thee idle will drop down and finally stall. Then I can't get it started until it cools off. Any ideas of what may be causing the problem?[/b]

It sounds like the stator or the CDI unit. I've replaced many on those models. Usually it's the stator because it's bathed in it's own motor oil, which can get VERY hot short out the coils.

Hope that helps.

Cycle Pro Racing, Inc
John