93 Gas DS jerks while running

[g22]

Hi guys,
My campground neighbor a 93 gas DS that is having issues. When it is running it seems like it just slows down and then picks back up. It happens at wot as well and medium throttle. It seems to happen intermittently. You are riding along and it just slows down abruptly then picks back up again. It seems like it is fuel starved except the engine does not die or sputter. Any suggestions or ideas would be appreciated.

Thanks

[rbsimons]

My 2000 gas DS was jerking at low to medium speeds but ran fine at high speed. I found a broken throttle return spring. Replaced spring now it will run at any speed smoothly. The spring is under the plastic cover above the carb.

[Mark27]

I agree! Sounds like the butterfly is not opening / closing fully.

[Springbok]

I had this problem on my '87 last year. Totally intermittent and random. I never figured out exactly what it was, but it was definitely the carb. I had a spare carb laying around, and once I swapped it out I never had the issue again.

[g22]

Thanks for the replies. Last week, the day I posted this I gave it a Seafoam treatment. The next day it seemed to run fine. My neighbor drove for about a day and a half with no problems. The next time she drove it, the symptoms returned. I picked it up again this evening. I noticed that when I drove it cold it seemed almost normal. As the engine heated up the hesitating began again. It seems to happen at all speeds. You hold the throttle steady and it slows down and picks back up. I am thinking the carb needs a good cleaning. Any other suggestions will be appreciated. I will check the butterfly in carb tomorrow to make sure it is opening and closing correctly. Thanks

[g22]

I drove the cart today and it did the same thing: I started it up cold and it ran well for a few minutes. When the engine got warm/hot, the hesitating starting again. Did not seem to matter where the pedal was. It would hesitate at slow to medium speeds as well as wot. It would hesitate for a second then pick back up. I removed the carb and the throttle return spring was intact, could it be stretched? I am going to get some carb cleaner this afternoon and clean the carb and see if that helps. Another thing I noticed is when the cart is stopped and the gas pedal is released (to kill motor), it makes a "whoosh" noise like air is being released. It is not backfiring.

[g22]

I took the carb apart and cleaned it. This helped the hesitating a lot. But now when you release the pedal to kill the motor it sounds like a light backfire or sometimes just a "whoosh" noise. Once the motor tried to keep running after the pedal was released. Any ideas?

[tpg]

Feel the underside of the intake hose to make sure there is not a hole, Backfires are usually a lean codition. Like sucking air in where it's not suppose to. Make sure the air cleaner tabs are in the slots at the bottom . It can suck air there.