Mercruiser 170 with cracked exhaust manifold

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gumsfamily

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I have a mercruiser 170 ( 470 series ) I have had an overheating issue and I have discovered a crack inside the exhaust manifold. Is this JB WELD able or where is a good place to find a used exhaust manifold. Note boat is not worth that much money at this point and I hate to dump too much money into it.
 
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stonyloam

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Re: Mercruiser 170 with cracked exhaust manifold

e-bay. check to see if you have cast iron or aluminum.
 
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gumsfamily

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Re: Mercruiser 170 with cracked exhaust manifold

It is a cast iron, I am considering brazing the crack. I went on e-bay and did not have much luck. Do I refer to motor as a 170 or 470?
 
Bondo

Bondo

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Re: Mercruiser 170 with cracked exhaust manifold

gumsfamily said:
It is a cast iron, I am considering brazing the crack. I went on e-bay and did not have much luck. Do I refer to motor as a 170 or 470?

Note boat is not worth that much money at this point and I hate to dump too much money into it.
Click to expand...

Ayuh,.... That's but a couple of it's many names....

Do a search in this forum for 470....

After ya read for awhile,...
Consider the thought of Sellin' yer's off as Parts....

Then take the profits, 'n go buy another boat, Without a 470...

Just sayin'....
 
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gumsfamily

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Re: Mercruiser 170 with cracked exhaust manifold

Unfortunately, this was my first boat and after much research after the fact, I see purchased one of the worst motors ever produced. It kills me because the boat is decent and we enjoy it. But it is for sale, and I am being honest with what is wrong with it.
 
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stonyloam

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Re: Mercruiser 170 with cracked exhaust manifold

In some peoples mind it is a bad engine, plenty of guys (including me) like them. If the only thing wrong is the manifold, you can try fixing it. There are a couple on ebay now, type in "470 exhaust manifold" what year is your engine?
 
Grandad

Grandad

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Re: Mercruiser 170 with cracked exhaust manifold

I used JB Weld for a cracked manifold on my 120 HP Mercruiser. The crack was several inches long at the bottom corner of the square exhaust manifold. I dressed the manifold and a piece of 3/4" angle iron, laid a trough of JB Weld in it and stuck it in place, proping it there until set and then painted it. It looked and worked slick for about 6 years and started leaking last year. I plan to do it again using 1" angle this time and perhaps tapping the manifold for a couple of 1/4-20 bolts. Kinda MickeyMouse, but ya gotta do what ya gotta do sometimes. - Grandad
 
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stonyloam

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Re: Mercruiser 170 with cracked exhaust manifold

gumsfamily said:
1985
Click to expand...

You should have the "new" style click on exhaust manifold here: http://www.mercruiserparts.com/selectDocs.asp?doc_nbr=12488 There are two types, aluminum and cast iron. The exhaust manifolds are interchangeable, however the reservoirs are not, so if you go with a aluminum one you need the reservoir to go with it. Anyway good luck with the repair. BTW a cracked manifold could have happened with any engine, and is a "470 problem".;)
 
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