1997 G11A YAMAHAULER utility cart... backfire upon stop.

[Miami_G11]

Hi all!

Adam here from Miami. Bought a 1997 G11A as a project work my 15 year old son. Would love some help from the pro's out there...

I'm having what I believe to be a carb/ fuel issue.
Every time I come to a stop I get a loud POP! (backfire) = so embarrassing. I had a local golf cart repair shop clean/ adjust the carb but it didn't solve the problem. The cart runs strong (26 mph with 2 (large) passengers)...but in order to run well the choke needs to be out a bit (using zip tie). Mechanic said the Yamaha fuel systems are complex but I'm curious if maybe someone had a similar experience?

Thanks in advance!

Adam

[mozzer]

First check would be the microswitch on the pedal or linkage, depending on model I think. If the there is too much throttle input without the switch clicking to run that could cause unburnt fuel.

I don't think the Yamaha fuel system is complex at all, but I have an old G9.


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[CP241]

Basically the same engine as a G9 except 300cc. No the fuel system is not at all complicated, just finicky.

First, make 1000% sure the airbox lid is 1000% completely sealed tight. One strappy clamp missing and its gonna run like dookie.

There is a plastic spacer between the carb and the head, make sure that is not cracked. They crack super super easy if you tighten the carb mounting bolts too tight.

Make SURE the carb says "MIKUNI" on the side. NOT "MOKINI" or anything else.

And check to make sure when you let off the gas pedal, the throttle plate closes all the way. If it is left even a little bit open, it's going to backfire, diesel, run-on, or a host of other things when going down hills or stopping. Its maybe being held slightly open by either the stop screw misadjusted, the cable between the governor and the carb being out of adjustment, or the cable being bad/sticking can cause this too.


That's where I would start anyway

[Miami_G11]

Originally Posted by CP241

Basically the same engine as a G9 except 300cc. No the fuel system is not at all complicated, just finicky.

First, make 1000% sure the airbox lid is 1000% completely sealed tight. One strappy clamp missing and its gonna run like dookie.

There is a plastic spacer between the carb and the head, make sure that is not cracked. They crack super super easy if you tighten the carb mounting bolts too tight.

Make SURE the carb says "MIKUNI" on the side. NOT "MOKINI" or anything else.

And check to make sure when you let off the gas pedal, the throttle plate closes all the way. If it is left even a little bit open, it's going to backfire, diesel, run-on, or a host of other things when going down hills or stopping. Its maybe being held slightly open by either the stop screw misadjusted, the cable between the governor and the carb being out of adjustment, or the cable being bad/sticking can cause this too.


That's where I would start anyway

Thank you I will be looking into this!