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powbmps

Sketchy Motor Repair?

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powbmps

1995 350 Mercruiser MTS. New to me, but 1,800 hours on the motor. Seems to run great, but noticed a fair amount of moisture vapor coming out of the valve cover vent on the spotters side. Compression is strong and oil on the dipstick looks good. Removed the manifold and found this:

Engine.jpg

Any thoughts on what the previous owner could have been up to?

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oldjeep

Cracked block from improper winterization fixed with JB Weld

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oldjeep

Although more correctly I guess I should say cracked head. I'd be looking around for more of the same at other locations.

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powbmps

Thanks oldjeep, I was getting the feeling it could be something like that. I suppose the excess rust in that area could be due to a water leak there?

So, my understanding is water can get to places it shouldn't be, but compression can still be good?

Edited by powbmps

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oldjeep

Sure. If the water jacket cracks externally you can have no compression loss or oil contamination.

Edited by oldjeep

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tccombs

Oh man... I agree with Oldjeep..

This is Not good. I would pitch a fit over that with whoever you bought it from unless they disclosed that to you..

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powbmps

It was not disclosed to me, but my hand written bill of sale says "as is". I am going to run it by the previous owner and see what he has to say. I would like to think he didn't know about it. I suppose it's possible the boat mechanic he always used did it to cover up a mistake in winterizing or something.

Edited by powbmps

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oldjeep

If that's the only problem area, I'd just put a reman head on it.

X2. Except I would replace both rather than mixing an 1800 hour head and 0 hour head.

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powbmps

Seems like new heads run about $1,000 or so. I am seeing some nice 300 hp longblocks for around $2,500 shipped. Hmmmmm.

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Michigan boarder

Go big, now's your chance!

post-8942-0-97284100-1432298645_thumb.jp

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Nitrousbird

Sure. If the water jacket cracks externally you can have no compression loss or oil contamination.

Yep, happened to my first boat's original motor. Block split on the outer jacket, spewing water. Some JB Weld worked for two years until the oil pump let go while running WOT, trashing the motor.

Seems like new heads run about $1,000 or so. I am seeing some nice 300 hp longblocks for around $2,500 shipped. Hmmmmm.

You need to shop around. GEN-I SBC heads are cheap and easy to come by.

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Baddog

Go big, now's your chance!

MB, I missed the end of your rebuild thread. Where did you net out for HP on that bad boy and what is your top speed? Also, do you have a sound clip?

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Michigan boarder

MB, I missed the end of your rebuild thread. Where did you net out for HP on that bad boy and what is your top speed? Also, do you have a sound clip?

395hp & 495ft/lbs torque with a 850cfm carb, but I chose to use my stock Weber carb and have 384hp with 474ft/lbs. Top speed is still only 45mph at 5,330rpm - I will be buying a different prop this spring/winter to reduce RPM.

powbmps - here's the thread on the full rebuild, taking it from 265hp to where it's at now at 384hp.http://www.themalibucrew.com/forums/index.php?/topic/46372-what-engine-would-you-put-in-your-boat/.

Personally, your boat still runs so I'd be hesitant to go thru all of that. Put a set of vortec heads on it and off you go. Is the engine fuel injected or carb?

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Lance B. Johnson

I would inspect the rest of the block thoroughly before just replacing the head(s). A crack in the head like that indicates that the water was high up in the engine and more damage was possible, like down on the block.

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Woodski

@powbmps: 1996 was the transition year for GM cylinder heads which basically bumped the power level from 265 to 310 hp. Rest of the components remained the same for the long block. If everything seems to run fine and nothing else shows up, I would certainly weigh the option of simply continuing to run the engine as is until it needs additional mechanical work. Although, assuming you are in the Northern Hemisphere, winter is the perfect time for attention to engine issues. A replacement for that head (and it's sister) should be very reasonable given the vintage and the improvement in the post 96 Vortec heads.

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powbmps

Thanks for the advice guys. Only a few weeks until I have to put it away, so I'm cleaning it up, putting it back together, and running it until then. I'll pull both heads off and check out the block. If it looks good, I'll just go with re-manufactured heads. If not, I'll go with a long block.

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gordon20mxz

It was not disclosed to me, but my hand written bill of sale says "as is". I am going to run it by the previous owner and see what he has to say. I would like to think he didn't know about it. I suppose it's possible the boat mechanic he always used did it to cover up a mistake in winterizing or something.

Did you ever contact the previous owner about this mystery repair? I would be interested in the story?

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powbmps

Did you ever contact the previous owner about this mystery repair? I would be interested in the story?

Sounds like he was the original owner of the boat, but has always had other people work on it for him. He has been bringing it to the most recent mechanic for the last 9 years. I suppose it could have been done in the 11 years before then. Easy to miss the repair if only routine maintenance has been done. The previous owner seems like a good guy, so the theory I'm going with is improper winterization, and a cover up by the mechanic whose care it was in at the time. He actually refunded me $200 to put towards new heads, so that's pretty cool.

Going to use an Ebay catch can to keep the extra moisture out of the carb for now. Hopefully the weather is nice enough this weekend to take it for a spin.

Catch%20Can.jpg

Edited by powbmps

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powbmps
powbmps - here's the thread on the full rebuild, taking it from 265hp to where it's at now at 384hp.http://www.themalibucrew.com/forums/index.php?/topic/46372-what-engine-would-you-put-in-your-boat/.

Great build thread! Still reading through it. My head is cracked exactly where yours was. Must be the weak spot when they freeze.

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Falko

If you are getting moisture there, you have water in your oil, that's bad. I wouldn't run it...

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powbmps

If you are getting moisture there, you have water in your oil, that's bad. I wouldn't run it...

I'm definitely getting moisture on one side of the motor, but it runs strong with no visible water in the oil and compression is good. Might get out a couple more times and will just keep a close eye on it. Fixing it over the winter.

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Baddog

This time of the year make sure you have a paddle and a phone handy. Just in case . . . . .

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