Join Date: Jul 2007
Location: Northern Virginia
Thanked 9 Times in 9 Posts
Rep Power: 10
Biocide is more to keep stuff from growing at the juncture between fuel and water, but it won't help what's already there.
I would replace the raw water impeller, since it has been bent in the same position for a while. I second changing the oil and filter, even though that looks good. A few cranks with the stop knob pulled out to circulate oil sounds good.
After you replace the fuel filters and bleed (don't crank down that bleed screw on the secondary filter too hard or you'll strip out the aluminum housing), I would not be surprised if it started right up. The full throttle just to start trick that denby suggests works for my 2GM20F, but I only need it in really cold weather.
And as others have mentioned, don't crank for too long with the raw water seacock opened to the engine (20 or 30 seconds total). Flooding the engine with water would be a lousy start.
2000 Beneteau 331
Northern Chesapeake Bay
Ambition is a poor excuse for not having enough sense to be lazy ~ Steven Wright