1990 mercruiser 4.3 no power in gear. Sluggish and rough

Joined
Jul 21, 2020
Messages
5
Hey folks. So I read a few posts about engine bogging down, however, I feel my case may be slightly different.

first time out ram awesome. I noticed a lot of water in bilge area. Turned out to be a cracked manifold. So I replaced both manifolds (other was cracked too) and risers both sides.

I also replaced spark plugs and gapped at .35.

changed fuel filter.

Changed the battery

today it started great. Go to get on plane and it’s like I’m towing a freight liner. Lots of vibration and sounds like crap. engine oil looked fine. No water leaks out of anywhere


Any likely culprits ?

also, on our first trip a dinged up there prop on the boat launch when I drove it onto the trailer. No major bends. Just small chunks missing. Could that possibly affect it this much ?

it ran better with two cracked manifolds lol.

serial #OD382045
 

Rick Stephens

Admiral
Joined
Aug 13, 2013
Messages
6,118
Recheck firing order.

When you changed the filter, did you dump contents into a clear container and look at it?

A dinged up prop can certainly cause vibrations. Look at it carefully to be sure it isn't bent to a different pitch.
 
Joined
Jul 21, 2020
Messages
5
Thanks! I’ll start there. I’ll dump the fuel filter and check. I’ll go through the spark plugs and make sure they’re in the right order
 

tpenfield

Moderator
Staff member
Joined
Jul 18, 2011
Messages
18,104
Gee wiz . . . 2 cracked manifolds . . . I wonder how that happened ??? :rolleyes:

What else might have cracked :noidea:

How's the engine oil look ??? chocolate or coffee milkshake?
 
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