www.iFourWinns.com

1994 horizon 180 5.0 omc cobra
Long story short, boat took on water. I am brand new to baits so I didn't diagnose that it was indeed water so I started replacing stuff. Fuel pump (mechanical), carb rebuild, anti siphon valve. Still ran like crap and wouldn't stay running. Well it was water in the fuel, so had it all sucked out and fresh fuel put in and bam she fires up happy. Sort of.

This issue I am having - and this is hard to describe in text so bear with me- when I first drop her in the water she will only start under throttle. But even when she does start it doesn't immediately catch up to the revs the throttle is at, it sorts of creeps up noticeably slowly, and if I slow it back down to no throttle she Will stall. Also she will rev up in neutral but if drop it into gear it bogs down and cuts off.

However, once she has warmed up it runs like a champ I can shut it off for an hour and she's fired right up with a touch of the key and no throttle at all. It's just when it's really cold do I have this issue.



Halp

Sounds like your auto choke (if the engine has a carb) is not working properly. You need to verify its proper functioning, some are electrically heated (heating element opens it) and some are heated by the exhaust crossover in the intake manifold (like on pre-vortec V6 and V8s). It should nearly close with a cold engine and when it starts, the vaccum break should pull it open a fraction of an inch (but still mostly closed). Then when the engine warms up it should be all the way open.
Are you opening the throttle all the way, before starting which allows the choke to close?
Are you manually setting the cold fast idle by advancing the throttle about 1/3 forward in neutral?



Looking at OMC parts diagrams, I'm thinking you have a Ford 302 (5.0) and it likely has a 2 bbl Holley, or EFI. A '94 boat could have a '94 or 93 power train. In this case the engine is the same but the outdrive is completely different from the '93 to the '94. I am very familiar with carbs but have never worked on one of these marine EFI systems. That 2 bbl Holley has an electric choke. Sometimes all it needs is to clean the choke shaft and linkage, to allow it to move freely so it can close when cold and open when hot. On a boat that age you might have to replace the spring because it may have lost tension.

Post up your model number, then I can say for sure.

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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