G2 intermittent stall/fail to restart

[DieselSJ]

My G2 has developed a new issue and it is driving me nuts trying to diagnose. It will run fine for weeks, then I'll get in and start it and within 30 seconds it dies and won't restart. It can do it while it is hot or it can do it when I first start it in the morning. Then I can go out the next day to start troubleshooting and it will start and run fine and run again for a week or so with no issues, then it will do it again.

Findings so far -
- Fuel - it is getting fuel. Fuel filter is clear and if I empty it, fuel will pump back into it. I don't think fuel is the issue.

- Spark - there was one opportunity that I did get to do some diagnosis and I checked for spark - I pulled the plug, and grounded the electrode and cranked it and got a very weak spark intermittently. As I was checking other things suddenly I got a strong spark consistently. Put the plug back in and it started and ran again for a week. I thought maybe wiring connection so I checked the harness for the ignitor and coil and made sure everything was clean (no corrosion) and good contact. Still having the issue.

I have checked wires, cleaned grounds, separated and cleaned connectors.

Thought about an ignitor but don't want to just start throwing $100+ parts at it.

Any thoughts or ideas?

[sho305]

Does it do it when it is more wet out, or hotter out?

I would check your wiring again, especially grounds. Wiring and connections are a common problem. Ignitor typically goes bad when hot, or completely dies due to bad connections. Some the plug comes loose inside or the wires do.

[smallblock450sl]

2 things come to mind. At he negative battery cable eye end at the starter, cut off the 18 gauge wire pig tailed into the cable eye let. Install a new eye let on the 18 gauge wire and reinstall it on the starter stud with the neg cable. Make shure the snap connector to the main wire Harness is free of corrossion. Unscrew the spark plug cap (counter clock wise). cut off an 1/8 or 1/16 inch to get a nice solid core connection, and screw the cap back on. My problem with grounding any Yamaha with an ignitor is, if the ground is lost, blow's the ignitor

[DieselSJ]

Originally Posted by sho305

Does it do it when it is more wet out, or hotter out?

I would check your wiring again, especially grounds. Wiring and connections are a common problem. Ignitor typically goes bad when hot, or completely dies due to bad connections. Some the plug comes loose inside or the wires do.

Does not matter temp or humidity. It has happened in midday heat and it has happened on a cool night.

Originally Posted by smallblock450sl

2 things come to mind. At he negative battery cable eye end at the starter, cut off the 18 gauge wire pig tailed into the cable eye let. Install a new eye let on the 18 gauge wire and reinstall it on the starter stud with the neg cable. Make shure the snap connector to the main wire Harness is free of corrossion. Unscrew the spark plug cap (counter clock wise). cut off an 1/8 or 1/16 inch to get a nice solid core connection, and screw the cap back on. My problem with grounding any Yamaha with an ignitor is, if the ground is lost, blow's the ignitor

Thanks. I'll start with those. Spark plug cap is brand new and I did trim back the end of the cable when I installed it.

[Spicyunicorn]

Pull the plug on the cdi box had one with same symptoms on of the spade terminals was corroded and had poor connection cleaned it and had been running great since

[DieselSJ]

Originally Posted by Spicyunicorn

Pull the plug on the cdi box had one with same symptoms on of the spade terminals was corroded and had poor connection cleaned it and had been running great since

Already did that and made sure all connectors were fully seated. This thing is driving me crazy. Went about a hundred yards up the street and died on Thursday and it would not restart so I had to push it back home (in 113 degree heat) and left it in the front yard. Saturday I went to move it to the back of the property and it started up and ran and I drove it around for a few miles with no issues.

[Flintrock]

Check the bowl on the carb for junk....drain and replenish the gas, might be bad.

[DieselSJ]

I'm about ready to just drop a big block in it and ditch all the factory wiring. It has been running great since the last time it died. Been driving it all around, probably have 5-6 hours of drive time on it with no issues. It just starts and goes. But I'm afraid to take it anywhere for fear that it will die again.