Strange happenings with OMC v4

[GatorMike]

I have an 89 crossflow V4. I've been having a problem lately. This makes no sense to me but for 3 straight days I have started the motor at home with the water hose hooked to it and it has started with the first turn of the key every time and runs beautifuly. On all three days I then took the boat down to the lake to give it a test run and the darned thing takes forever to start and runs like crap. Then I get the boat home and it runs like a dream again. Any Ideas?

 

[OBJ]

Re: Strange happenings with OMC v4

Mike....they always run real good outta the water. Why? No back pressure against the cylinders provided by being in the water. Give us a little more info. <br /><br />How long you had the engine? Is it new to you or is this a problem that just cropped up? Do you know how long it's been since the engine was checked over...like compression test, spark test, carbs overhauled?<br /><br />This will help.

 

[GatorMike]

Re: Strange happenings with OMC v4

89 OMC seadrive same motor as 110 Johnson<br />compression -- 100 psi 3 cyl 93 psi in one cyl.<br />Ignition system -- getting spark to all cyls.<br />Fuel system -- seems to be getting gas carbs reciently rebuilt.<br /><br />One thing I wonder about, the problem first started after I replaced the water pump impeller. Not sure if this could be a clue or not.

 

[Solittle]

Re: Strange happenings with OMC v4

Have you pulled the thermostats? Those motors do not run well in the water unless they get to operating temp. I have a pair of 1987s.<br /><br />You need to decarb when you get a chance or check the compression with a different guage. Mine check out at 110-115.<br /><br />I doubt that the water pump is a factor.

 

[paperdesk]

Re: Strange happenings with OMC v4

I'm not familiar with that model, but isn't there supposed to be a valve that lets the exhause out above the water level? Could it be that the above water exhaust system isn't functioning?