new to me boat 350 merc need pointers before more damage

skinny1965

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ok I'm in Ontario Canada and just picked up a new to me boat it's 8cyl was told 350 but has blown head gasket where do I find all the drain plugs and stuff to ensure the rest of the water is out before freezing
I just want to be sure of no more damage
 

alldodge

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ok I'm in Ontario Canada and just picked up a new to me boat it's 8cyl was told 350 but has blown head gasket where do I find all the drain plugs and stuff to ensure the rest of the water is out before freezing
I just want to be sure of no more damage

Going to need more then " I have a 350", have a serial number, or at least a year?
 

alldodge

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I havent gotten to the serials yet but it might be early 80's

I'll use 1982 to 1986 unless told otherwise
There will be one brass plug on each side of the block below the exhaust manifolds. It takes a 7/16 wrench and watch you don't ground the wrench against the start terminal on the starboard side. Once plug is removed stick a wire up inside or small screw driver to clear any blockage.

Remove the hoses off the bottom of the exhaust manifolds

Under the engine there should be a power steering cooler, look for a 7/16 brass plug on the bottom an do the same as the block. If you cannot get to the plug or it's not there remove the hose and let water drain out.

Remove the large hose on the bottom of the circulating water pump
 

alldodge

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OK appears you have a 78 to 82 model with log style exhaust manifolds.

Should work out about the same
 

Buoybill

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You may want to check you tube for : How to Winterize an I/O Boat using Inboard/Outboard Kit, Step by Step Guide [h=1][/h]
 

airdvr1227

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OK, since no one else is saying it I will. In the spring you might find more problems than just simply a blown head gasket. Many boats are sold with cracked blocks that mimic a head gasket issue. YMMV. I hope it isn't for your sake.
 

skinny1965

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well looks like the motor has way more issues than I was lead to believe got at it this morn for bit was going to seal off some of the hoses and charge it with water to make sure block was ok
well when I grabbed my garden hose it was frozen so I decided to pull manifolds while I waited for hose to thaw . well once they are off the plugs are right there so I figured I would pull them and see if I could figure which had the bad cylinder. well 7 of the 8 plugs produced water or water oil sludge and lots of it. so not looking very good but hey you can turn it over with a j bar
 

flipbro

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This is a simple one. That motor is toast. Pull motor strip it down keep what's good then find yourself a good truck block.
 

skinny1965

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ok so I do think I found a motor so other than the outside stuff what internal things should be changed I have heard cams are way different
 

alldodge

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ok so I do think I found a motor so other than the outside stuff what internal things should be changed I have heard cams are way different

You want a truck motor not a car motor that's the cam difference. Need marine head gasket, brass freeze plugs and marine circulating water pump.
 

skinny1965

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I found motor not sure if truck or car what different in the head gasket was thinking I would swap the cam out of motor in boat
and all other stuff off outside of motor
 

Bondo

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Ayuh,.... The marine head gaskets are ssteel based, not carbon steel which rusts away,....

Unless this motor came outa a Hot Rod, don't worry 'bout the cam,...
What's in it will run just Fine,....
 

flipbro

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Since your in Ontario I wouldn't be to worried about marine head gaskets a good felpro set will serve you well.I to live in southwestern Ont and have rebuilt a few SBC for marine use and never had a head gasket failure.Also be sure the donor motor is a two piece rear main 1985 and erlier you will befine. I would spend the 100 bucks and by a new rv cam off ebay.Just your basic grind 443/420 is a nice upgrade for a stock 350. Make sure it comes with new lifters.
 
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