89 OMC 2.3L smoking and overheating.

Hey everyone new to the forum. Working on my dads boats today. Replace spark plugs, Thermostat, all gaskets, New impeller pump ( old one rotted away) and Fresh new oil/ Filter change. But the boat starts just great and sounds amazing But the it is overheating. Temp gets above 180 and White smokes comes out of the exhaust under the stern. I have seen threads for possible blown head gasket. BUT i am doubt of it being that. the engine just sounds to good for it to be that. So if anyone could give me some input i would appreciate it. I do have experience with car engines and figured Marine engines are basically the same design with minor changes for water use. Thanks everyone for your future advice.

Re: 89 OMC 2.3L smoking and overheating.

Check for plugged lines between the out drive and the engine, If the old impeller we chewed up then chances are there or pieces of it clogging the lines. Although white smoke is a really really bad sign of a blown head gasket.

Re: 89 OMC 2.3L smoking and overheating.

Profile,location??
Why you working on it?
Did it run ok before?
Compression test? Will tell if the gaskets blown??
Check impeller,and check the passagways for pieces of the old impeller.
They can flow through the hoses and block the thermo.
Unfortunatly the exhaust manifold and riser aren't available anymore.
So if the riser's clogged it's gonna be hard to find parts.

Re: 89 OMC 2.3L smoking and overheating.

Hey everyone sorry i didnt fill out my profile last night. But anyways the boat is a 1989 Bayliner Capri Cuddie cabin. with the 2.3L OMC. 3 years ago boat ran great then the last time we took it out that summer we had a freeze plug break which caused a few problems but we fixed the Then last summer we took it out on a very nice day mid 70's. Bot ran great for about an hour or so then noticed it started to run hot and white smoke coming from the stern while in water. Took her home pulled apart found the Impeller to be burnt all up( probably original). Well had a lot going on so it sat the rest of summer and winter in a big pole barn that doesn't get below 45 degrees. So this past sunday it was 60 degrees bought and out in new Impeller, plugs, thermostat, fresh oil change. We did get a lot of impeller pieces out of the Thermostat housing and the house from the impeller to thermostat. Everything from Impeller to Therm is free of debris. Now the impeller is working great boat fires right up and sounds amazing. But will still heat up to past 185 or more with the white smoke heavily coming out of the exhaust under the stern prop. I will be really disappointed and surprised if the head gasket is blown .Engine just sounds to good for that to be the problem. How would i go about doing a pressure test?

Re: 89 OMC 2.3L smoking and overheating.

I would think that if you see "for sure" steam, it would be water intrusion in the cylinder/s. You might check the plugs and see if there is water.

Re: 89 OMC 2.3L smoking and overheating.

bonzoscott said:

I would think that if you see "for sure" steam, it would be water intrusion in the cylinder/s. You might check the plugs and see if there is water.

Click to expand...

I will be working on it again on friday. I know the difference between steam and smoke. Seems to white to be steam, BUT has a oder to it which makes me think Smoke. I did find that i can buy a AUTO GRADE Head gasket from pepboys that is for a 2.3L ford Mustang engine and the images of the two are IDENTICAL. So if it comes to be a blown head gasket. Will the auto grade work?

Re: 89 OMC 2.3L smoking and overheating.

I have the same boat and had a similar problem. Turned out that my head was cracked! I however had a miss fire in the cylinder that was leaking. The head is very very easy to pull off and the re/re can be easily completed on a weekend. Try pressure testing the cooling system with 20 + pounds of pressure then pull the spark plugs and see if any water accumulates in the cylinders.
Just a though? A compression check may also reveal clues. Do you have oil and water mixing ? The frost plug blow out sounds weird?? Either freeze damage or rot ?
Anyway one last thing to do is to perform a cylinder leak down check. This sometimes reveals answers

Good luck Stuart

Re: 89 OMC 2.3L smoking and overheating.

Overheating ?Clogged thermo or a clog in the hoses.
Or the riser is clogged.How hot is the riser?
Have you checked the exhaust downtube? Sometimes the flapper melts and cloggs the exhaust?
Drop the drive and see if the flapper is down in the exhaust tube??
You sure the parts of the old impeller are out of the system?

Re: 89 OMC 2.3L smoking and overheating.

Hey Everyone Sorry i never got back to any of you. I just started a new Thread with almost the same subject. Since all these problems i have replaced anything with the cooling systems impeller gaskets and all. New Thermstat cork washer and gasket. verified all lines are free of debris. The problem i have now is that i have water coming into the engine but there is zero water discharging out from the exhaust vent tube under the stern or from the propeller. So i am now puzzled as to where a blockage could be. I did take apart the exhaust down tube to find that the flap was completely melted so i removed it and free any debris from the tube. Only place i haven't not checked yet is the manifold. Are there any other locations that anyone could suggest to check? Any help is appreciated. Thanks

I have recently had a similar problem with my 4.3. What I found was a slight adjustment to my timing was needed for both the white smoke and the overheating to stop. I also found that my choke had stopped opening automatically. The excess fuel was combusting in the chamber, didn't have enough air to burn off, entered the exhaust on the exhaust stroke then fired again by the next cylinders discharge. Fixed the choke and most of that stopped. Then found the timing was off by 6 degrees advanced. Fixed that and my overheating exhaust stopped being a problem. Also on the topic of your overheating... if you have the OEM exhaust manifolds. Check the waterflow through them. Mine were rusted so bad that they had no flow, thus overheating. Found that wonderful surprise after a new engine. Then got the aftermarket replacement had slag from the mold process clogged it water outlet. This boat now performs great. Hope this helps. Dont know if you fixed your yet or not