4.3 Down, but is it out?

[Lakes84]

Hi everyone

Fishing has been great on Lake of the Woods, but the boating not so much.
I have a 1987 Sport Craft with the 4.6 v-6 gm motor in it. I'm hoping it's
just a head gasket. The motor is not hydro locked, it does still run. It just
is real hard to start and not good at idling. When I pulled the plugs they
were all good (maybe running a little rich) #2 was wet with water. When I
turned it over, around a quarter of a cup of water came shooting out and it
really wants to start then. I shut her down, pulled it out of the water. Then
turned it over to expel the water from the risers and the #2 cylinder......
Of course the oil is milky.

The #2 plug when inspected had no inner electrode and the other part (that you gap)
was broken off. This plug when pulled for the first time was cross threaded and not screwed
in all the way and two of the others were finger loose. So I'm sure that antagonized the whole deal.

My question is, head gasket or exhaust manifold? Secondly, if I need a new motor, I can get a crate
vortec for it, but what parts would I need to successfully to a swap out the 87 OMC I have now. OR
would it be better to to just rebuild if the block checks out fine, I've read the crate motors are built
in Mexico and are not very robust. Thoughts?

Thanks!

Joe

 

[Don S]

Re: 4.3 Down, but is it out?

Likely just the risers and/or manifolds. Pull the risers off and look at the gasket surfaces (after the old gaskets are cleaned off) that is where they usually leak first.
Head gasket wouldn't get water in the cylinders, more likely into the oil and the oil would be milky.

 

[Bondo]

Re: 4.3 Down, but is it out?

Ayuh,.... Has that got those Batwing manifolds,..?? If so,.. There's yer problem....

Yer gettin' ahead of yerself,...
Get it dried out, 'n run a compression test to see how healthy the motor is...

 

[Lakes84]

Re: 4.3 Down, but is it out?

Thank you for your responses. It's a relief that it's more than likely a riser or manifold. Hopefully that spark plug didn't damage anything when it came apart. Will do a compression check in a day or two. Thanks again.

Joe