G9 Gas Engine Timing

[lightman45]

I didn't get a reply with a solution to my previous post. See previous post below.

I recently purchased a G9 cart that had been sitting for quite a while. It had water in gas tank. I drained gas tank, put on new carburetor, intake, and fuel pump, adjusted valves, put in new plug. Cart fires up fine when cold and runs fine as long as you keep running. When you stop when it is hot it doesn't want to start back up. It even pops and back fires some of the time. You can let it sit for a few minutes and it will fire right off and run fine again, until you stop again. I have run out of ideas. Does anyone know of things that I need to try next to get this problem solved.

I have a little dog that is paraplegic and cannot use his back legs, and he loves to ride the golf cart. I try to ride him at least once around the block every evening. The back firing scares him pretty badly, need to get fixed.

Thanks for your help, Jim

I was wondering if the ignition timing was adjustable on this engine and how to do it, and if that could be my problem. Also, someone suggested to me that the muffler might be partially clogged up since I am smelling a strange odor when it gets hot. I smell it some when riding, especially since putting windshield on cart, but mostly after stopping. Could this be causing the problem, and is there a way to repair without buying a new muffler.

I have drained and cleaned gas tank, put on new carburetor, new spacer between carburetor and engine, new fuel pump, new gas line, new spark plug, and adjusted valves. I have checked air filter and made sure air filter box is sealing. I need suggestions on what to do next.

Thanks again, Jim

[Chompy]

Does the backfire make loud bang or a muffled pop? Is the carburetor a stock Yamaha carb or did you get a Chinese aftermarket?

[lightman45]

The carburetor is a stock yamaha model. The backfire sounds more like a muffled pop than a bang. Hope this helps, Jim

[Chompy]

A muffled pop usually means that the engine is "backfiring" through the carburetor. Most of the time this happens it is because of a lean fuel/air mixture. Check your carburetor settings and make sure the rubber seal on the upper lid of the air filter box is intact and seating all the way around.

[lightman45]

I have checked and rechecked the air filter box and it looks to be sealing fine. The backfiring is through the muffler and not the carburetor. Sounds almost like the timing is off. When it is cold it cranks fine with a little choking, and it runs fine until you stop when it is hot and try to start again. At this point it is very hard to start, and somestimes backfires when trying to start. Thanks

[Barry Wilson]

Loosen the muffler to see if it runs a little better. A muffler that old may be partially clogged, especially if it had water in it.

[Chompy]

The timing is fixed. It is not adjustable. When the cart stops on you pull the plug and see if it sparks. Better yet, use a dynamic spark tester to see if it is sparking. When ignition systems start to fail they usually fail when they get hot so it is not out of the question that the problem may be electrical. Checking for spark when warm will eliminate that question.