Dirthead

I hope you might be able to provide some advise. I have just bought a 1995 272 Islander Baja with a carbureted Generation V Merc 454, SR number OF413462, with a Bravo 1. The first 3 times I have had it on the water (fresh water only boat) it has overheated. The first time I took it out it overheated, 230 degrees F, right away. As soon as I heard the warning buzzer go off, I shut the engine down and then heard every cylinder fill up with water (this boat does NOT have through the haul exhaust). The engine was very hot (boiling water when splashed on the block, but there was NO water in the engine compartment and NO water in the engine oil). I towed it to the marina and they rebuilt the fresh water pump (the veins on the old pump were all intact and looked fairly good) and replaced the bellows boot. Took the boat out for the second time and the same time happened, but this time it would get hot only if you ran it at half to full throttle. If you went back to idle or lower throttle, the temp would go back down. I took it back to the same marina and asked them to replace the recurculation water pump. They did not and said that would not be the problem. They went through it again and found no problems. They checked every hose looking for restrictions and found none. They did replace the thermostat. The next time I took the boat out we ran it for 3 hours, at full and half throttle, and had no problems then all at once, it got hot again. I turned the engine off and heard the cylinders gurgling and belching and filling up with water again (again no water in the engine compartment and no water in the oil). I pulled it to my business( I own a trucking company and have our own diesel repair shop). We did a compression test and showed good compression on each cylinder, thus somewhat eliminating the possibility of a blown head gasket. Again with no answers, I took it to a different marina. They removed the circulating water pump and said it looked good. They also looked for restrictions in all the normal places and found nothing. They were stumped and did not know what to try next. I picked it up from that marina and took the boat to yet another marina and had them look at it. I had them replace the exhaust flappers with a new style (although the old ones appeared to be just fine). They also did a leak down test and said that it leaked compression in between three cylinders. I picked the boat up, brought it back to our shop, and removed the engine. I pulled the heads, the gaskets looked just fine, with no signs of being blown. I had the heads magnifluxed and they tested out just fine. I pulled the frost plugs and thougt that the block might be full of sand however found no sand inside. Needless to say, I am at a total loss as are the 3 different marinas that looked at the boat.

Would you have ay ideas as what to try next? I would love to fix this issue while the snow is on the ground so I can actually BOAT in the summer. My thoughts next are to replace the exhaust manifolds and risers. If they are cracked, I could see how water could be leaking out, across the intake manifold, and into the cylinders. I also am planning on replacing both the recurculating and fresh water pumps as well as any intake water hoses.

I would be open to replacing the heads or exhaust manifolds if it would resolve the problems. Money is an issue, but ultimately I just want to get the problem fixed. I plan on putting in a new cam and intake manifold while the engine is out.

Are there any intakes on the Bravo 1 drive that could be blocked or plugged? Each marina that has looked at the boat has told me that there are none that could be blocked.

Any ideas? Where would you look? If I am to replace the heads, intake manifold, cam, exhaust manifold, water pumps, ect… What would you suggest?

I sincerely appreciate your help.

Thanks,

Adrian, The bummed Baja owner in Iowa!

offshoredrillin

I had a similar problem on a 383 stroker motor, just blowing water out the exhaust (truck), while you have the motor out have you looked at the cylinders for cracks? and also check your intake manifold. I've seen sometime where overtorking puts stress on it and a crack underneath lets water leak into the heads then down past the valves. hopefully its not cracked cylinder walls, but check there as well. That would explain a leakdown as well.

Tricky919

I had a problem similar to yours and found that my oil cooler was clogged causing a restriction. I pulled the end cap off and cleaned out the tubes with a welding rod and the problem was gone.....Might not be your problem but worth a look.

offthefront

well ....mine did the same thing ...ok at slow speed or idle ....got hot when you got up on a plane and it was the thermostat ... I see you changed that ..does it have the stock cast iron exhaust ? if so ...check inside and see if there are signs of water running down the risers back into Exhaust Manifolds ....I would Def change the exhaust ...

Doller Offshore

did any of the marinas inspect the water inlet hose in the gimbal?there ia a insert
on this hose that either fails or gets clogged

Dirthead

They claim they inspected the inlet hose by the gimbal.

HiPerf2000

i would look at the exhaust. Common for the original cast iron manifolds to fail and cause internal water leaks.

Scott

Check the hose from the Gimbal to the water pump. Is it reinforced or has it been replaced with the wrong type of hose that may be collapsing when the pump is running higher rpm's?

Griff

Where the heck are you boating in Iowa in in the middle of winter??????

First suggestion would be to find a marine mechanic that you trust and that knows what he is doing. The ones you've been to are chasing a ghost

What do you mean when "rebuilt the sea pump"??? Did they just replace the impeller or did they install a complete kit with new housing???? If they didn't replace the housing and its worn, it won't suck in enough water at higher rpms.

I hope you're not hearing water in your cylinders, as you say. If there's H2O in the cylinders and has been several times, you'll need a rebuild. You might hear water boiling in the block????????

My guess is you've got/had a restriction somewhere that is moving around enough to let enough water in intermittently. You also could have had several other problems get created by the original overheat. You should have a 140* in that engine. Mine would never get above 160* on the guage.

Dirthead

God no I am not boating in Iowa now, my problems were from late summer and I am just now taking another look at the problems. The marina “rebuilt” the sea pump by replacing the guts and impeller. I do not believe that they replaced the housing. I had water in the cylinders. When I pulled the plugs, I blew water out of each cylinder. I have pulled the heads, and the cylinder walls do not look bad at all. A light hone and they should be fine. I believe we put in a 140* thermostat. We have looked everywhere for restrictions but still do not find any.

As far as finding a mechanic that I trust, I am not moving around out of disgust of the mechanic. The boat has been taken to different mechanics because they all seam to be at a loss as where the problems lie. Thanks for the suggestions.