[mmcta550]

My XP doesn't want to start, although after about 10 minutes of cranking and giving it some throttle it will eventually start, run really rough until it warms up, and then once warm will only restart if you give it a bit of throttle.

I didn't have this problem until I put it on a trailer and trailed home in a nasty rain storm. Initially I figured something in the ignition was wet. But after almost 2 weeks of indoor storage I figured I needed to diagnose. So far, here is what I have done:

1. New spark plug
2. New air filter
3. Checked fuses and relay (for the EFI)
4. Cleaned the throttle body
5. Disconnected and reconnected the spark plug wire from the coil
6. Checked spark - plenty of spark

After cranking for 5 minutes and no start, I checked the spark plug thinking it would be very wet. To my surprise, it was not wet and was sparking strongly. The plug looked like it wasn't getting fuel.

After another 5 minutes of cranking and giving it full throttle, it eventually starts and runs rough for the first couple minutes (won't even idle). Then once warm it runs normal, but if you shut it off you have to give it a touch of throttle.

My next try is going to be draining the gas completely and putting fresh gas in. Any other ideas of what might cause this?

 

[Bruce!]

Welcome to the board.

 

[BlkPrl1000xp]

Maybe do a compression test? How about valve clearance?

Sent from my SCH-R970 using Tapatalk

 

[TXRonnie]

Stop everything you are doing and do a compression test. Some 09's and early build 10's have been known to have valve problems including mine. If it show low compression you will know the hard starting issue. Don't just adjust the valves have the vlaves checked to make sure they are not getting flat. You have the same exact symptom as mine did. Hope it is something else.
How many miles to you have? Mine did it the first time at 1600 miles.

Ronnie

 

[mmcta550]

First, thanks for your responses, I appreciate your help.

I drained all the gas last night, put new gas in with heat water remover (safe for ATV's on the bottle) and was able to rule out fuel or water in the fuel.

I will do a compression test tonight and see what I get. My next step was to check the valves but I wasn't sure how big of a deal getting the valve cover off is. Any idea on what compression I should be looking for?

My atv has 1,941 miles on it and too my knowledge (I bought it used from a friend), it has never had any work done to it.

Thanks
Mike

 

[faawrenchbndr]

Any idea on what compression I should be looking for?

70-90 psi

 

[TXRonnie]

Have you had a chance to do a compression test?

Ronnie