www.iFourWinns.com

Fuel injected or carbed?
If FI cold start enrichment valve, temp sensor, if carbed, choke not closing, or closing and not getting pulled open by the choke pull off.
With FI sometimes a defective fuel pump will let pressure bleed off when the engine is off and you have hard starts when cold.

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88 Four Winns 200 Horizon
4.3 OMC Cobra-4bbl
2002 Walker Bay 10/2012 Suzuki 2.5
2008 Walker Bay 8

1998 Jeep Grand Cherokee 4.0/Selectrac
2007 Jeep Grand Cherokee 5.7 Hemi/Quadradrive II

I would check the IAC (Idle Air Control) valve. I'm not a motor head, but I did replace mine while trying to diagnose a hot starting issue. There is a plunger that slides back and forth to control the air mixture. If it is stuck, it may be the right mixture for a warm engine, but the wrong mixture for a cold engine. That's my understanding of it anyway. Someone correct me if I'm wrong.

Sorry Alan, the IAC controls the desired idle as commanded by the ECU, although it does assist with cold start high idle. The bandwidth injector pulse richens or leans out the required mixture. Myty, try a coolant temperature sensor. If it's giving the ECU a warm temperature input when the engine is in fact cold, the ECU wont command the injectors to go rich for cold start up. They are cheap and easy to change.

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07 Azure AZ200,
Previous boat,
95 278 Vista,
And a lot of others.

Ontario, Canada

It also helps to let folks know what model and year boat it is. Update your signature with the info, and your profile's location.

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-Bill Kearney, 2005 348 Vista