G9 project- need help
 

New guy on here, hope I'm doing this right.
I purchased a yamaha g9 (400$) for a project to work on over the summer. It was previously someone else's unfinished winter project that needed to be completely rewired, front suspension fixed, new air box installed, gas lined redone, and various nuts and bolts missing replaced, but supposedly ran great before he deconstucted it. I have fixed all that, but i cannot get it to run properly. When i press the gas it will fire right up and run- until i release the gas, at which point it will shoot a puff of gas out the carb and will not run again unless left alone for a day or so, probably a flooding issue, but i cant figure out why.

Re: G9 project- need help
 

They are supposed to stop when you take foot off pedal, that is how golf carts are. It may be flooding or fouling the plug with the airbox unhooked. The box must be sealed together unless the carb has been jetted differently, they are really sensitive to that for some reason. Also get the newer yami cart plug for it, the ngk2bprs or whatever is run in newer yamahas, it works better is more resistant to fouling.

If it will not turn over again, that is an electrical problem with the switch or solenoid, possibly the generator. In that case check all the wires and connections first they are a known issue on these older carts. Especially check ground wires nothing is grounded to frame it all uses ground wires.

Re: G9 project- need help
 

The cart does stop when the pedal is released, just shoots that one puff of gas at the end. The wiring is all good, healthy spark and always turns over, but the problem does persist with the air box on, have to do some airproofing I guess, and I will replace the plug with the newer one. Thanks for the help.

Re: G9 project- need help
 

I guess I would set the valve lash iirc it is .004", then test compression and see where you are at. It might be tired or need a valve lap. Also turn it over by hand and watch the rockers, see that they both move as it opens the valves. If one only moves a little bit then the cam is bad and can cause it to puff out the carb. Could also check muffler make sure it is not plugged, though not common on G9 I have heard of it. Will cause backpressure like that. It may be somewhat normal a lot of small engines will revert intake a little when they stop since the cam is advanced from crank rotation or the crank turn backwards from compression before it stops.

Make sure you seal the rocker cover, if oil leaks out it goes down into the fins and fills them with dirt....it will run hot then.

Also try setting the carb so it idles really slow just faster than the gen turns it, fine tune the mixture when it is warmed up so it idles nice and smooth and slow (when pedal is just on). It should start better. It may work better yet to turn the idle mix out a little after that. I never use the choke in summer with mine set that way.

Re: G9 project- need help
 

The compression is great, but I've wanted to mess with the carb mixture, but have no idea how, any tips on that?

Re: G9 project- need help
 

Most have a idle mix screw on the side its below the idle speed at the top. This only affects up to about 1/8 throttle opening. The main jet takes care of the rest, you have to change that if you have issues at higher throttle. When I start my cart I push the pedal down about half way then let up to idle, then half again, repeat. It starts faster this way and the idle mix affects it. I don't let up enough for it to stop turning over and this cart will idle running the pedal has about an inch of travel from start to when the carb actually opens...I set it that way.

Also make sure the carb spacer is not cracked, people overtighten them and they crack causing a vacuum leak and messing up low throttle/idle mixture.

Re: G9 project- need help
 

replaced fuel lines, filter, new spark plug, sealed air box with silicon goop, still having the same flooding problem after initial run, the person who had this before me had it wired for a key start, would this effect the carb/gas issue?