[srponies]

I'm trying to help my neighbor with his '02 90. It has the 2-stroke motor. He said that he's had problems for a while. When he dropped it off - it had no spark. I found a bad pigtail connection. Now good spark. 90lbs compression. Seems to be good fuel flow to carb.

It has a K&N type filter. I removed that and had to cover the carb inlet partially with my hand to get it to start. Then it was quite peppy for about ten minutes. Then it began to backfire, bog, and lost throttle response. If I give it any more than minimal throttle, it bogs bad. Eventually it quit.

Tried to start after that but just wore down the battery.

It seems to have good spark. I don't know what would change after warming up. Not sure if I need to go thru the carb or what.

Any ideas greatly appreciated.

Steve

 

[Sanny651]

Check the coil when it's hot...check for spark when it's hot. If the coil is bad, when it warms up it can fail.

 

[srponies]

Thanks for the idea. I did check a few things when it quit today. I pulled the plug and checked compression (85lbs), and checked spark (good). That makes me think it is a fuel problem.

Steve

 

[Sanny651]

Check to ensure it's not vapor locking and that your gas tank vent is working.

 

[srponies]

Well I think that I may have figured it out. It seemed to me that something was happening when it warmed up to bog it down. I thought - what usually changes between cold starting and warm running? The choke.

This quad has an electric choke. I removed it from the carb. I don't know exactly how it's controlled/timed, etc - probably thru the CDI or something. But I do know that when I put 12V to the power lead nothing happened. The plunger didn't move. So I'm thinking that maybe it's at full choke all of the time.

Electric choke assembly:

I am considering just putting a spacer under the plunger to raise it and see if it makes a difference. Maybe converting it to a manual choke.

The replacement electric choke is $80.

Any other thoughts on this?

Thanks,
Steve

 

[Sanny651]

Didn't know it had an electric choke. Sounds like you got 'er figured out.