Water in spark plugs

[Karlomora]

Hi, I have an 1988 omc cobra, 4.3 liters. When I sraterted at home it did start, but temperature was going little hot up to 175, I changed temperature gauge. Put in the lake drove for 10 minutes then start getting hot reaching over 200 degrees. Turned off, let cool down for 4 hours. Didn't want to start back up. I have towed. Got home, check points, coil. Didn't start. Pull all spark plugs out, found water in all of them. Any ideas how I can fix this or what to check on it.
Thank you for your help.

 

[Bondo]

Ayuh,...... Welcome Aboard,...... Ya probably gotta rebuild the raw water pump, 'n replace it's impeller to fix the overheat,.....

Water in the cylinders can be Alota things,.....
If you've got the one piece exhaust manifolds, they are suspect,....
A cracked intake manifold is possible,....

Isoluate the Block, 'n pressure test with compressed air, after it's drained,....

 

[Lou C]

As Bondo said air pressure test the block/ heads first then remove exhaust manifolds and fill with acetone to check for leaks….
If you need new manifolds I did the 2 piece conversion with Barr aftermarket & V/P exhaust pipes & hoses. Fit perfect….

 

[Karlomora]

Ayuh,...... Welcome Aboard,...... Ya probably gotta rebuild the raw water pump, 'n replace it's impeller to fix the overheat,.....

Water in the cylinders can be Alota things,.....
If you've got the one piece exhaust manifolds, they are suspect,....
A cracked intake manifold is possible,....

Isoluate the Block, 'n pressure test with compressed air, after it's drained,....

I put a new impeller few month ago. Will try to follow your advices. Ty.

 

[Lou C]

The one piece manifolds have pretty small outlet holes and they can clog fairly easily. Here's a set of mine after 5.5 seasons in salt water. I had 3 sets of these on my engine and replaced them every 5-7 years which is pretty typical here.
I then converted this engine over to the later style using Barr Marine aftermarket manifolds and elbows and used V/P 90* exhaust pipes and hoses. If yours are bad, you can do it this way (a little pricey because of the V/P parts but that's a one time expense) or GLM makes a conversion kit, that is actually cheaper, but in the past their quality was questionable. The ones I installed fit like factory, no leaks and have held up very well.

 

[Karlomora]

The one piece manifolds have pretty small outlet holes and they can clog fairly easily. Here's a set of mine after 5.5 seasons in salt water. I had 3 sets of these on my engine and replaced them every 5-7 years which is pretty typical here.
I then converted this engine over to the later style using Barr Marine aftermarket manifolds and elbows and used V/P 90* exhaust pipes and hoses. If yours are bad, you can do it this way (a little pricey because of the V/P parts but that's a one time expense) or GLM makes a conversion kit, that is actually cheaper, but in the past their quality was questionable. The ones I installed fit like factory, no leaks and have held up very well.

Thank you for the information, I will pull the intake out and check how that looks. Will keep you posted.

 

[Bondo]

Thank you for the information, I will pull the intake out and check how that looks. Will keep you posted.

Ayuh,..... Don't do that til ya do the block pressure test,.....

The intake is apart of the block pressure test,.... the exhaust is not,....

 

[Lou C]

Agreed take off the exhaust manifolds first & test with acetone. Then go from there

 

[Horigan]

First priority is getting the water out of the oil and cylinders. Change the oil, then run the starter with the spark plugs out and the fuel pump relay pulled. Put a towel over the spark plug holes so water doesn't spray every where. You may want to bring each cylinder up to top dead center and try to pull water out of the cylinders with a rolled up paper towel. Spray WD-40 and/or fogging oil spray in the cylinders. You'll probably have to change the oil twice. If it takes a while to repair the leak (new exhaust or intake manifold), be sure to run the starter briefly every few days so pistons and cylinders don't rust together.

 

[Lou C]

I had to something similar with my leaky head gaskets, run till hot, drain all water change oil, repeat. My HGs would leak not when running but when the engine sat for a day. Just a little water. Also sprayed fogging oil like mad. Was able to save the long block & installed reman cyl heads. Old heads were cracked from past overheat. Still running it 5 years later with the new center riser exhaust.

 

[Scott Danforth]

Hi, I have an 1988 omc cobra, 4.3 liters. When I sraterted at home it did start, but temperature was going little hot up to 175, I changed temperature gauge. Put in the lake drove for 10 minutes then start getting hot reaching over 200 degrees. Turned off, let cool down for 4 hours. Didn't want to start back up. I have towed. Got home, check points, coil. Didn't start. Pull all spark plugs out, found water in all of them. Any ideas how I can fix this or what to check on it.
Thank you for your help.

you took a boat that was getting hot in your driveway to the water? and expected anything less than an overheat?

I put a new impeller few month ago. Will try to follow your advices. Ty.

did you find all the missing pieces of the prior impeller?

how are you testing at home in the drive. with muffs, or attempting to suck up from a bucket?

Hint, if you attempt to suck from a bucket, you toasted your impeller.

 

[Karlomora]

Ok, here are the new things on my boat. I let it run at home with the muff and water hose, the old impeller was in a good condition, but since I pull it out, I just replaced with a new one.
So I pull out the thermostat. It really was stuck and very bad condition. I leaving it without a thermostat just to test the boat. I dried the cylinders and crank the motor few times, enough to spell oll water out from cylinders, all new spark plugs installed. The boat starts like never nothing happens. Temperature goes to 145. Looks and sounds good. Pull sparks out, I didn't find no more water. Wonder why it have water when I put the boat in the lake the first time.
Will try to put in the lake next week. Will keep you posted. Thanks for the comments.

 

[Scott Danforth]

I leaving it without a thermostat just to test the boat.

your thermostat is used as a mixing valve. without it, your block will run hot.

 

[Horigan]

Is there water in your oil? Did the oil level increase?

 

[Karlomora]

Is there water in your oil? Did the oil level increase?

Hi, no, no water in the oil and it didn't increase. I check the compression in the engine, looks good. Cylinder 1 have 142 and the rest have 150. It starts, sounds good, didn't get hot, only to 148 degrees with the muffs and water on it. No thermostat for now, just trying to see was wrong. Will install the thermostat as soon as I get this right.
But my problem starts when I put the boat in the lake.

 

[Karlomora]

Well, I am back. So I decided to take off the exhaust manifold, it was those wholes blocked, no cracks, I have give a nice clean up, also the 2 flapper were destroy, one was missing, I replaced them, now I am putting the manifold back, please does anyone knows what is the torque for the nuts.??
I am replacing lots of hoses, spark plugs, thermostat. I hope it will run great.
Thanks for your help.

 

[Karlomora]

Hello, so I installed the exhaust manifold back, new thermostat, new hoses, new flappers, one was missing. I started the boat with ear muff on it. Runs great, temperature a little under 175 F.
Over the weekend I will take to the lake to taste if there is no mo water going into the spark plugs. Will keep you posted. Thanks for all your advices.

 

[Lou C]

On the OMC 4.3 with the 160* stat, my temps were usually from 160-170 or so, highest was just after coming off plane where it would go almost to 175 briefly but then cool down. You can check for water in the cyls even after just running it on the water hose, warm up engine, then ground high tension lead from coil to distributor cap, open throttle andcrank over. Look for water hopefully none.