Yamaha G9 Overheating

[Ebrownrigg]

I previously asked about my 91-94 Yamaha g9 overheating! I found a crack in my carburetor spacer joint so I replaced it! Still running hot after running for about 10 minutes ( results in loss of power). Could this be a timing issue or would it run hot all the time if timing was off? Ty

 

[HotRodCarts]

If the timing is advanced to much it can cause the engine to run hot. Have you checked for grass or other debris in the fan cover?

 

[Ebrownrigg]

I will, ty

 

[Rstaley]

What symptom convinces you that it is overheating. Poor performance can be caused by lots of things. The timing (cam shaft rotation relative to crankshaft rotation) on that model is established by gears, not a chain or belt. Has anybody had the engine apart who might have mis-assembled It? I’d sure try to pin down the poor performance a little bit further to be sure that it truly is overheating. Other than that, the air flow from the fan would be the most important thing as has been mentioned by Hotrod.

 

[Ebrownrigg]

I will take it back apart and check everything over again! By power loss, I mean, it doesn't have the response it had before I completely rebuilt the engine! It takes about 2 seconds to respond to me dropping the gas pedal to the floor, and if I have someone on cart with me it heats up fast and can barely go up a hill. And I mean not a big incline either!

 

[Rstaley]

Before I’d take it all apart, I’d pull off the valve cover and watch the valves go up and down as I rotated the crankshaft through all 4 strokes. I’d see if the valves were both really closed at TDC before the power stroke, see if there is excessive valve overlap between exhaust and intake, etc. Perhaps you messed up on the valve adjustments. How does the compression test? There should be something fairly obvious causing all of that grief. It wouldn’t hurt to do some more testing before you take it back apart. Good luck.

 

[Ebrownrigg]

Thank you so much! I will check that before I pull it all apart!

 

[classycarts]

Thank you so much! I will check that before I pull it all apart!

Does it backfire through the carb at times?

 

[Ebrownrigg]

It use to, but hasn't since I replaced spacer joint.