89 4.3 omc rough idle and water in cylinders

[Alterd88]

I recently bought an 89 kayd 18ft deck boat, when i looked at it it started right up. Checked the oil no milky residue (head / or cracked block issue).Which was good. I took it out once to check it out it started but ran rough . I couldn't get it to stay running. Itook it home checked the water separator and replaced it. The fuel was orange with alot of sediment. Replaced spark plugs. Was goin to take the carb apart to get all the sediment out of the bowls but i didnt'. I did however start the process removed the four bolts then removed the hose to the choke. But i reinstalled everything. I started it and ran good with the muffs. A little hesitation to throttle response but cleraed up as i let it run. Now the problem, Took it out ran pretty good had to feather the throttle to get up to speed but it stayed running. I met a friend on the lake and floated for a couple hours, went to start it and nothing. It tried to run idled around 400 rpm thn died it wouldn't go any higher. Got pulled in and i pulled the spark plugs and water in the cylinders but none in the crank. HELP!!!!!! Any suggestions THANKS!!! Happy fathers day wanted to take my kids out on the water. At least i did that part.

 

[Bondo]

Re: 89 4.3 omc rough idle and water in cylinders

Ayuh,... If it's got the 1 piece exhaust manifolds,.... They're Leaking Junk...
Replace 'em with 2 piece units...

 

[Alterd88]

Re: 89 4.3 omc rough idle and water in cylinders

Thanks! It has two manifolds sperated one on each side, is that what you meant? Any suggestions about the rough idle and hesitation? I am still planning to rebuild the carb. Other than that the motors good.

 

[ENSIGN]

Re: 89 4.3 omc rough idle and water in cylinders

Without doing a pressure test of the engine cooling system you have no way of knowing if the engine is any good.

 

[Alterd88]

Re: 89 4.3 omc rough idle and water in cylinders

5 out of 6 cylinders read 150psi with 3-4 revolutions. One reads 110psi. I replaced the plugs put the muffs on and started it but i noticed the exhaust tube has holes in it. Also when i turned the water on it water was comin out a seep hole away from the muffs. Does the exhaust tube have to be totally sealed ? Thanks for the help

 

[Bondo]

Re: 89 4.3 omc rough idle and water in cylinders

It has two manifolds sperated one on each side, is that what you meant?

Ayuh,... It's a V-motor, of course it has 2 manifolds,... 3 if ya wanta count the intake...

OMC once used 1 Piece exhaust manifolds, rather than seperate Manifold,+ Risers...
The 1 piece manifolds, commonly called "Bat-Wings" are a Known Problem, in that they Leak water into the motor....
If you have them,... Replace 'em with a 2 piece system, which means there'll be 4 pieces to the 2 manifolds...

 

[Alterd88]

Re: 89 4.3 omc rough idle and water in cylinders

Thanks for the reply. Yeah they are the batwing exhuast. I will look into the manifolds. Also, do the rubber tubes on the upper end to the drive for the exhaust have to be sealed? The one on mine has holes in it where the pleats are, looks like from age and rubbing on the guide. My six yr wants me to put the faces.

 

[Bondo]

Re: 89 4.3 omc rough idle and water in cylinders

The one on mine has holes in it where the pleats are, looks like from age and rubbing on the guide. My six yr wants me to put the faces.

Ayuh,... The Bellows, outside the hull, under the drive are Wet inside,+ out...
And,.. I believe OMC put those slits in 'em.... (faces enough for the kid??)

The rubber couplers, Inside the hull, Must be sealed...

 

[Alterd88]

Re: 89 4.3 omc rough idle and water in cylinders

Thanks for both. My son's over here laughing. He was upset the boat wasn't working. The idle issue can be due to the carb? When i replace the water separator, the fuel was orange, and had some debris in it. I know with my auto, anything can foul up the jets, needles and such. the wierd part is we took it out the night before fo a test run and it did fine no water in the cylinders. i replaced the plugs and it ran better. Can this be an intermittent issue? I still want to replace the manifolds. So far i can't find some for a 89. i found some for a 93. I guess with some work mods i can make them work

 

[Bondo]

Re: 89 4.3 omc rough idle and water in cylinders

So far i can't find some for a 89. i found some for a 93. I guess with some work mods i can make them work

Ayuh,... I've seen "Kits" for the Mercruisers with the Problem manifolds,...
But, OMC is outa business,+ you'll probably have to self-engineer a solution yourself on your boat...

Yes, it's Possible, maybe even Likely you have a Carb Issue from the Crud you found...
But,...
Leaking manifolds can also create these Problems, from water running back down the exhaust...

 

[Alterd88]

Re: 89 4.3 omc rough idle and water in cylinders

I might have made a rookie mistake? I left the stern drive up all the way while sitting in the water all that time. With slots in the bellow allowed water to get pumped back through to the manifold (filling the cylinder with water). I didnt lift the stern when i tested it out the night before. Does that sound like it can happen?

 

[Bondo]

Re: 89 4.3 omc rough idle and water in cylinders

With slots in the bellow allowed water to get pumped back through to the manifold (filling the cylinder with water).

Nope,.... No how, No way...

 

[Alterd88]

Re: 89 4.3 omc rough idle and water in cylinders

Is there a valve the doesn't allow it to back flow?

 

[skeat]

Re: 89 4.3 omc rough idle and water in cylinders

That's why these are called exhaust risers, they raise the exhaust above the waterline of the boat so it doesn't sink. Though there are also exhaust flaps in the collector tubes to minimize any backflow in certain conditions but more than likely they are gone

 

[Alterd88]

Re: 89 4.3 omc rough idle and water in cylinders

Is that gone due to age of the boat i.e. just worn out, or they havent put them in for a while. I took the boat out again after the water was cleared out. this time I did not raise the prop all the way up. And it ran without problems until i was goin back to dock and ran across some shallow area and raised the prop and reversed it. imediately after it i tried to start it and the same symptoms arose and i just got it started and revved it up for about a couple minutes and it was good.?????

 

[Brinman7]

Re: 89 4.3 omc rough idle and water in cylinders

new to forum and I have the same issue. I bought a 90 Four Winns, boat is on immaculate condition but cuts off after running a while and want start back up. I took plugs out and they had a little water on them. I cleaned them off and put back in, the boat fired right up. After research online I found several people saying to replace exhaust manifolds with two piece ones. I dont want to if I dont have to. I was wondering what you did if anything to yours to correct your problem.

 

[Alterd88]

Re: 89 4.3 omc rough idle and water in cylinders

I haven't done anything to it I leave the prop down when I'm in deep enough water. I haven't had that issue occur again.