g9 starting issue

[jaybird28510]

I have a Yamaha g9 gas golf cart that I just purchased. It started but ran rough. I tuned it up, new plug, air filter, and I even bought a new carburetor and the spacer that goes between the carb and engine. it runs better but doesn't go when I press the gas pedal. I can see the starter motor turning but the belt doesn't spin. it seems to only be able to spin the motor over until it hits the compression stroke of the motor. do these engines have an automatic compression release or is there a way to tighten the starter generator belt? I don't know much about golf carts and am learning as I go. I just don't want this to be an expensive teaching with no problems being solved. any help is greatly appreciated.

[DOOmsman]

Is the starter belt slipping or is the starter stalling?

[dirttoo]

Jaybird seems to be describing my problem too. I have an '89 G2. Even with the battery fully charged the motor barely turns like one revolution at a time really slow. Anybody have any suggestions?

[sho305]

Check all electrical connections, battery clamps, ground cables/wires, older yamaha are notorious for issues there but easy to fix. The brushes may be bad in the gen, they can be replaced make sure you label the wiring....assuming you are getting full power at the gen. Test the voltage at battery and gen it should be close under load. If you find a hot spot in wiring after trying to start that is the problem area. They do not have comp release far as I know but the ignitor does go to zero advance at starting. You can set the valve lash and inspect rocker movements. In comp release engines you will see one of the rockers move a little in the compression stroke as you turn it over by hand. Make sure you have the ignition off or disable it if you turn it by hand. If the belt slips it will make a chirping noise typically and you hear the gen going at high speed.

[jaybird28510]

thanks for all of your help. sorry it took so long to reply, I just returned from being out of town. I took the starter apart and the bearings are shot. the brushes aren't anywhere near the wear mark. im going to replace the bearings and see if that saves me from having to buy another. no wiring issues, the voltages are good.

[sho305]

Should be able to repair the gen no problem unless the windings are damaged or bearing cup/shaft/mounting are damaged. Make sure you wire it right if I didn't mention that, easy to mix it up. Diagrams are posted here.