Question for everyone. A\C 500 auto, 2000. under no load, in neutral, reving up the engine slowly, when the throttle reaches full the engine runs like crap. Like it is running rich. I tried cleaning the air filter. No luck. There is no adjustments on the carb accept for idle. I tried a hotter plug. still te same. Tried different fuel. No luck. Went the other direction; lean. I put some duct tape partially over the air intake. Still no luck. Anyone have this problem, or have any suggestions? My top speed is about 46, don't know if this is good or bad. It seems to be a dog at top end but getting there, everything else seems ok.

 

Not sure but It might be a rev limiter , so you don't over rev it up and blow your motor .
Is it running ok under normal abuse [img]i/expressions/face-icon-small-smile.gif[/img] ? If not you might have a problem with the coil .

 

Thats about right for a top speed 45-55

 

Try with out filter, we have had some filters get bad enough that they did not clean well. If you still have a problem you need to determine if you are rich or lean. Are you putting out black smoke? Does it cut out under load? Your top speed should be better, I have not seen a 500 auto that won't do at least 55 MPH. Also might check your valve clearances.

 

Tork, Yea it does put out some black smoke. Can I change the main jet to the next one smaller? I'm assuming that thats how you do the carb adjustments on this?
Thanx

 

If it just started suddenly your main jet is not the problem, you are looking for either air restriction or over fueling. Air restriction could come from air filter or intake tube. Over fueling could be needle and jet tube (usually causes flooding at idle only), or from float valve not seating or O-ring around seat not sealing off. Try with air filter removed to eleminate that first. Always try simple stuff first, not only easier but usually fixes problems.

 

I don't know if the problem started suddenly. I just bought it in Oct. I just noticed it one day. I tried no filter and it did the same thing. It runs fine at idle. But it seems like it's getting too much gas. The plug is black when I removed it. I need to check with the dealer to find out it there is a rev limiter on the machine.

 

trop,
I had a similar situation with my 400i. It would run just fine, but under load it sputtered and just seemed to bog down. I had more power at half throttle than at full throttle. Solution.....bad gas. The gas was quite old and from the summer time. The gas just barely had a smell to it but it was enough. I removed the carb and took it to a mechanic (who used to work at Honda dealer). He cleaned it and then I removed all the gas and replaced with fresh gas, as well as a bit of carb cleaner/injector cleaner in the fresh gas. Works fine now.