Why Won't My ATV Idle Without Dying?

Rick Sosebee
by Rick Sosebee
Why won’t my ATV idle without dying? This is what a Honda Foreman owner wants to know and he asked the ATV AnswerMan for help.

Here is exactly what the reader asked the ATV AnswerMan, followed by his response:

I have a 2000 Honda foreman 450 ES 4×4. Cold starting the ATV and it starts up and runs for a second perfectly fine. No matter if it’s hot or cold it will not idle. After a few seconds of running it starts spitting and sputtering and will eventually die completely and won’t start back for a few minutes.

This is probably the most common question I get here in my email. This seems to be more common with machines that sit often and do not get used on a normal basis. As I have mentioned in the past, today’s fuel situation is tough and is only getting worse. Fuel has more ethanol than ever before mixed in and this causes slow fuel delivery due to varnish as well as horrible running from bottom throttle up through the full throttle position. Gelling of the fuel occurs as quickly as a few weeks and this can cause the delivery from the tank to also be slow. As for the problem you are experiencing, let’s take it just a little deeper in case you’re the one percenter.

Fuel needs to flow into the fuel bowl unrestricted. Simply loosen the float bowl drain screw on your Foreman and allow a little fuel to run out into an approved container for a few seconds. This will tell you how quickly the fuel is getting into the carb. Once it has been determined that fuel is flowing into the tank you can move on to fuel delivery in the carb. If the fuel has varnished the primary or starter jetting then you need to clean those jets. This is not a simple procedure, as the jets need serious chemical cleaning or simply be replaced. If the problem persists then you may need to dip the entire carb or have it professionally rebuilt/cleaned by a dealer. I would also look for any restrictions like kinked vent hoses on the tank or carb and any venting that provides an airway to the carburetor.

On a lighter note, you could simply have water in your fuel that only gets picked up once the demand for fuel is increased. Check all of these things out and get back to us!

Rick Sosebee
Rick Sosebee

Whether he is in Mexico covering the Baja 1000, building ATVs for local racers, or out enjoying the trails, Rick’s passion shows in his stories. Learning to wrench his own machines from his grandfather, Rick also has an undying appreciation for the mechanics of off-road vehicles. Do not let the dirt and mud fool you, though, as Rick also has a deep love for street cars.

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