2004 250 HPDI Cold Start Stalling

[TipsyMcStagger]

I've owned this engine for just under a year. It's got about 100 hours total time. Regardless of whether or not I pump the primer bulb, the engine will start, idle for anywhere from five to 30 seconds and then stall. It'll do this from six to a dozen or more times before it'll stay running at idle. It will also do this after sitting for a month or only a day. It's an issue only when the engine is cold.

Once running and in gear, it runs flawlessly. If I shut it down while fishing, it fires up immediately and idles flawlessly. This is only an issue if the engine is cold.

I know these engines drop two cylinders at idle, but the boat is kept on a lift and I can't just force it into gear immediately after starting in an attempt to keep it running.

The engine has had all updates, including the latest oil injection pump.

I've done a bunch of research and know this is not an uncommon problem. But most discussions I've found simply speculate about the possible cause(s). I found little to no definitive information regarding a solution.

I've read recommendations to check the TPS and the resistance of the spark plug caps, but again...these are only suggestions. None of what I've read has pinpointed the problem.

Any help is appreciated.

TIA.

Tipsy

[TipsyMcStagger]

Anyone?

Tipsy

[Tucker]

I'm shooting from the hipTipsy. Sounds like it starves for fuel and possibly loosing prime; fuel running back into the tank. Sounds like it's running on the fuel in the VST and then dies. But you say it does this even when you prime the bulb right? Does the bulb get hard? Do you have to pump it for a while to get it hard? Check valve in the primer bulb bad?

[TipsyMcStagger]

I'm shooting from the hipTipsy. Sounds like it starves for fuel and possibly loosing prime; fuel running back into the tank. Sounds like it's running on the fuel in the VST and then dies. But you say it does this even when you prime the bulb right? Does the bulb get hard? Do you have to pump it for a while to get it hard? Check valve in the primer bulb bad?

It takes six or seven pumps to get the bulb firm.

But if the problem were with the bulb, wouldn't it stall regardless of whether or not the engine is warm?

Tipsy

[Tucker]

Ok I re-read your post and now really scratching my head. You said it dies whether you pump the bulb or not right? So on a cold engine, you pump the bulb until hard and the engine runs for 5-30 seconds and dies correct? To rule out the LP fuel pumps, maybe pump the bulb after starting the engine and see if it continues to run or stall. (Grabbing at straws now) Pop in on THT and see if anyone else has had this problem.

[TipsyMcStagger]

Update: Brought her to the local Yamaha service center. Mechanic said he adjusted the throttle plates, TPS and performed a de-carb.

Engine now idles perfectly.

Very satisfied.

Tipsy

[Tucker]

Great news Tipsy! You were right on with your early assesment of the TPS. I think there's a thread on here from the rodbold that explains the procedure for adjustment. Bet your running Ring Free now... Thanks for following up with us.