Yamaha G9 won't fire

[Moose0013]

Originally Posted by CP241

See my thread G9 bogs and stalls... stumped.

Sounds very similar to what I was chasing. I could pull the plug and have spark. It would run GREAT for a couple minutes when I first got in it then it would die and nothing. Ignitor got wicked hot near where the connector is located. Just because you have spark doesn't necessarily mean it's strong enough to do anything either.

Or what I did was set TDC and mark the top of the primary clutch with a neon green paint pen. Grab a timing light and ride it around the yard until it dies. Once it dies, put it in "neutral" (shifter straight up) and keep the has pedal depressed so it keeps chugging. Shoot at your paint mark with a timing light. I'll bet you've got nothing.

I tried 3 brand new ignitors in it with the same results. They were all the aftermarket one, it appears that no matter WHO you buy it from amazon, eBay, golfcartsunlimited, etc) it's all the EXACT same one. They even use the same picture. It's junk. Either buy an OEM Yamaha for $300 or I did the Chrysler ignition module trick and it runs awesome. Hasn't had a single issue since I put it in.

I'll look up your thread, but what is the Chrystler ignition module trick?

[CP241]

http://www.buggiesgonewild.com/gas-y...s-stumped.html

See the last page in the post. Links to what I bought and I drew a quick diagram showing how to hook it all up. $30 in parts and I couldn't be happier!

[Moose0013]

I read your post and it seems as if you were losing spark randomly. My cart, on the other hand, will start up immediately and run like a top, so long as I have my foot on the gas pedal. So, I dont think I'm losing spark. It's only when i let off the gas pedal that it shuts down (as it should). Trying to restart it is when in have problems. I've found that if I hold the gas pedal at 10% (just enough to engage solenoid) and full choke, it may, or may not, restart, but that's the only chance I have of restarting.
The battery, coil, and starter generator all show the same voltage while under load and no wires get hot what so ever. Anybody got any other ideas?
I've got a video of it running and how it acts trying to restart, but I'm unable to upload the video. Says file is too large.

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[CP241]

Mine would start up immediately and run great for a short time. Then it would stop. If I tried to start again it may run for a short few seconds but then quit. If I waited 20min it would start up immediately and run great but only for a couple minutes then it would sputter, backfire through the carb and die.

Still running Chrysler setup and zero problems since making the switch. For $30 I'd say it's definitely worth a try. Worst case if it doesn't change anything, it rules out your ignitor and you can return the parts.

[Moose0013]

Originally Posted by CP241

Mine would start up immediately and run great for a short time. Then it would stop. If I tried to start again it may run for a short few seconds but then quit. If I waited 20min it would start up immediately and run great but only for a couple minutes then it would sputter, backfire through the carb and die.

Still running Chrysler setup and zero problems since making the switch. For $30 I'd say it's definitely worth a try. Worst case if it doesn't change anything, it rules out your ignitor and you can return the parts.

I guess it's worth a shot. Thanks for the help!

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[Moose0013]

Just a quick follow up to whomever may be following:

I was getting too good of a spark for there too be an ignition problem. And compression checked out at 145 (originally), so it had to be a fuel issue. So I went through the cart, double checking everything for a second time. I broke down the carb (again) and this time when i removed the needle, I realized that the viton tip was still stuck inside, on the seat. So I replaced the carb and gaskets with a new OEM carb. I bolted everything in place, and still... nothing!
Next, I removed the valve cover and checked spark again...good. checked compression again...nada! Zip, zero, zilch!!! Now, I was really stumped! I had compression before and now....none!
On the verge of giving up and taking it to a competent small engine mechanic, my co-worker volunteered to come look at it.....
We removed the valve cover and he turned the motor by hand and said, "yep.. no compression." He glanced over it for a minute and reached down and with a roll of his fingers, popped the valve stem back into its seat.....like magic, I had my compression back and the cart fired up like there was never a problem!!!
Turns out, that when i checked the valve springs by hand two weeks ago, i accidentally dislocated the valve stem from its seat giving myself more problems to chase than just a bad carb needle.
I feel like a dork but I'm glad my buggy is running again. Hopefully this thread can help somebody in the future!

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