G9 Stops running after 10 minutes

[Ktrilla]

I have a Yamaha G9 that I restored and changed out the piston rings. Runs great for about 10 minutes then stalls out. Any ideas?

The next day it usually runs fine… starts right away. No smoke or anything suspect. It’s almost like it is either flooded or not getting good fuel.

[slonomo]

My first guess is that it's not getting fuel. When it stalls, check to see if there is fuel in the carb or use a spray bottle with gas in it and spray it into the carb and see if it fires up. It might be using the fuel in the carb bowl and not re-filling it fast enough. If that's the case, the carb probably needs disassembled and cleaned. Also your fuel pump might be suspect, they do go bad when the get old, the rubber diaphram can deteriorate. Check all your rubber fuel lines and make sure they aren't old and hard and cracked. When the fuel lines get old and hard they can leak vacuum, replace them at that point. You could have a condition where the fuel pump is pumping, but very slowly, that could be a bad pump or bad fuel hoses. There is also fuel filter in the bottom of the tank, bad design, but most of us remove that and eliminate it, in favor of a clear inline fuel filter, $5 at the parts store.

[Ktrilla]

Thanks for the reply, you are always helpful. A few quick thoughts:

Carburetor was installed new in fall of 2020
Fuel pump was installed in on fall of 2020
All new fuel lines installed May 2021
New fuel filter installed in 2020… but it was a pain and I considering the inline option when I drain the gas this winter.

I worried that I don’t have a good seal or small hole somewhere that is causing the issue you described. I will run it until it stalls and check the carb out as you noted.

What size fuel line do you recommend? I am thinking I may have used a line that is to small… especially as I think about how difficult it was to hook up to the fuel filter, fuel pump, and carb.

Stay tuned!

[slonomo]

I think the fuel line I use is 1/4". 3/8" is too large and often won't fit over the fittings. If you have a fuel hose that is too tight, just warm it up, I use a propane torch and just touch the hose with the tip of the flame, usually slips right on.

[grantspec]

Could be the ignitor I’ve heard of them cutting out when they heat up. Have you checked spark when it cuts out?


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[Ktrilla]

UPDATE:

This weekend I went through all the hoses and made sure everything was on tight. I switched out a few old hose clamps to ensure a tight seal. I was missing one on the fuel pump… added clear fuel line from the pump to carb to make sure that fuel was moving through as expected.

Good news it is running great. Not sure what was the problem but it seems fixed.

Thanks for the help!

[slonomo]

Bad fuel hose....classic golf cart issue.

Glad you got it fixed!