1972 Mercruiser 165 Inline 6

83mulligan · Jul 16, 2013

I have a 1972 Mercruiser Inline 6. It was running fine when I put it away. It has sat in storage for 4 years (since I pulled it from my boat). Went to try and start it over the weekend. Its locked up and won't turn. I removed the plugs and poured a can of seafoam into the cylinders. I've been letting it soak. Is this engine junk now or is it worth something on the market? Should I spend any more time trying to free it up and run it or is that a waste of time. How much is it worth complete in this condition? Thanks.

Bondo · Jul 16, 2013

Re: 1972 Mercruiser 165 Inline 6

83mulligan said:
I have a 1972 Mercruiser Inline 6. It was running fine when I put it away. It has sat in storage for 4 years (since I pulled it from my boat). Went to try and start it over the weekend. Its locked up and won't turn. I removed the plugs and poured a can of seafoam into the cylinders. I've been letting it soak. Is this engine junk now or is it worth something on the market? Should I spend any more time trying to free it up and run it or is that a waste of time. How much is it worth complete in this condition? Thanks.

Ayuh,.... Pull the drive to make sure it's the motor, 'n not the drive,...

They turn together,... shiftin' is done at the prop shaft,..

83mulligan · Jul 16, 2013

Re: 1972 Mercruiser 165 Inline 6

Drive is pulled. Engine is on a pallet. Plugs were oily, but it doesn't want to turn.

Bondo · Jul 16, 2013

Re: 1972 Mercruiser 165 Inline 6

83mulligan said:
Drive is pulled. Engine is on a pallet. Plugs were oily, but it doesn't want to turn.

Ayuh,... Have ya tried barin' it over,..??

As for Value,.... It's worth atleast .10 a pound as scrap,....

The Parts, can be worth Well over that, providin' ya find somebody runnin' the motor, 'n wantin' Parts,...

Get it Runnin', it'll be worth upwards of a Grand, or more, dependin' on condition,...

83mulligan · Jul 16, 2013

Re: 1972 Mercruiser 165 Inline 6

Anything I should try in addition to sea foam?

ddrieck · Jul 16, 2013

Re: 1972 Mercruiser 165 Inline 6

I have used good ol'e Coke-a-Cola in the past with good results. Just pour some down through the spark plug holes and let it sit. Try barring it over after a day or two. If it still doesn't want to move... add more coke and repeat. May take a while.

83mulligan · Jul 16, 2013

Re: 1972 Mercruiser 165 Inline 6

What's the best way to put some leverage on it? There is the spline coupler on one end and water pump and mounting bracket on front.

83mulligan · Jul 17, 2013

Re: 1972 Mercruiser 165 Inline 6

guys, any thoughts on the best way to get some leverage on it. Like i said above, there is a spline coupler in the back and the mounts block the nut up front. Thanks!

Bondo · Jul 17, 2013

Re: 1972 Mercruiser 165 Inline 6

Ayuh,.... If you've got a splined shaft the fits the coupler, try that,...

Pull the starter off, 'n pry on the ring gear teeth,...

Are all the spark plugs out of it,..??

83mulligan · Jul 17, 2013

Re: 1972 Mercruiser 165 Inline 6

Bond-o said:
Ayuh,.... If you've got a splined shaft the fits the coupler, try that,...

Pull the starter off, 'n pry on the ring gear teeth,...

Are all the spark plugs out of it,..??

Yes sir, plugs are all out. It's been sitting a couple days. I'll try and put the outdrive spline in and turn it by the prop. It will be awkward but I think I can prop the drive and try and lever it that way.

Bondo · Jul 17, 2013

Re: 1972 Mercruiser 165 Inline 6

83mulligan said:
Yes sir, plugs are all out. It's been sitting a couple days. I'll try and put the outdrive spline in and turn it by the prop. It will be awkward but I think I can prop the drive and try and lever it that way.

Naw,... Separate it at the U-joint,.... ya can't fight the mechanical disadvantage of the drives gears,...

83mulligan · Jul 17, 2013

Re: 1972 Mercruiser 165 Inline 6

Seperated at U-Joint like you said. Got the shaft to make about a quarter revolution then stuck again. sprayed in a little pb catylist and will let it sit a few more days. First 5 cylinders look pretty good with a flashlight but the forward most one i can see some rust on walls.

83mulligan · Jul 30, 2013

Re: 1972 Mercruiser 165 Inline 6

Ok, been using a catylist and trying to move this every few days. I can rotate it about a half turn and then it sticks in the same spot and I can't budge it from there. What's next? More time and patience or do I need to pull the head and see what's going on and try and clean that way?

achris · Jul 30, 2013

Re: 1972 Mercruiser 165 Inline 6

Time to pull the head. It's not a long job, and will give you clear definition as to the 'salvage-ability' of the engine...

83mulligan · Jul 30, 2013

Re: 1972 Mercruiser 165 Inline 6

All the cylinders look pretty good when i shine a light in there except the most forward one. I can see rust in there that they cylinder comes up against and wont go through.

83mulligan · Aug 1, 2013

Re: 1972 Mercruiser 165 Inline 6

What's the process? Pull the head, clean it up, put back together and test compression?

83mulligan · Aug 5, 2013

Re: 1972 Mercruiser 165 Inline 6

Ok guys, I had some time tonight and pulled the head. This is what I found........

What is the next step here to try and get it running.

83mulligan · Aug 5, 2013

Re: 1972 Mercruiser 165 Inline 6

And why is that cylinder holding fluid (oil and catylist and the others are not?

Bondo · Aug 6, 2013

Re: 1972 Mercruiser 165 Inline 6

83mulligan said:
And why is that cylinder holding fluid (oil and catylist and the others are not?

Ayuh,... That motor ain't gonna Run again, without a trip to a Machine Shop, for a full overhaul,...

83mulligan · Aug 6, 2013

Re: 1972 Mercruiser 165 Inline 6

I want to get rid of it. What's it worth to someone who wants to rebuild it or have it rebuilt?

1972 Mercruiser 165 Inline 6

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