Manually spinning over a 1975 Mercruiser 165 L6

UncleFluffy

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Nov 1, 2013
Messages
16
Hey All.

Recently I purchased a 75 Reinell V-1901 with the Mercruiser 165 I/O. However I fear the motor may be slightly seized as it had been sitting for awhile and one spark plug was pulled. The oil still looks great in the pan so that's a bit of a plus. My question though is this. I'm going to soak it with some kerosene/atf mix but how do I spin the engine over manually as there is no way to spin the crank because of the front mount and the crank doesn't have a bolt to put a bar on. I'd rather not pull the starter and risk damaging the ring gear teeth. Any ideas? I got this boat for a song and I'd like to play around with it before it starts to snow and maybe have it running so that when May Long weekend comes next year, I'll have a boat that will be ready to hit the lake.

Thanks in advance for any help with this matter.

Happy Boating!
 

Bt Doctur

Supreme Mariner
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Aug 29, 2004
Messages
19,093
Where do you live?
Can you get a old inputshaft?
Do you have access to a welder?
 

Bondo

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Apr 17, 2002
Messages
70,468
Hey All.

Recently I purchased a 75 Reinell V-1901 with the Mercruiser 165 I/O. However I fear the motor may be slightly seized as it had been sitting for awhile and one spark plug was pulled. The oil still looks great in the pan so that's a bit of a plus. My question though is this. I'm going to soak it with some kerosene/atf mix but how do I spin the engine over manually as there is no way to spin the crank because of the front mount and the crank doesn't have a bolt to put a bar on. I'd rather not pull the starter and risk damaging the ring gear teeth. Any ideas? I got this boat for a song and I'd like to play around with it before it starts to snow and maybe have it running so that when May Long weekend comes next year, I'll have a boat that will be ready to hit the lake.

Thanks in advance for any help with this matter.

Happy Boating!

Ayuh,..... Welcome Aboard,.... Have ya pulled the drive yet,..?? it turns with the motor, 'n could be the problem,.....
 

Fishermark

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Oct 19, 2003
Messages
5,617
... I fear the motor may be slightly seized as it had been sitting for awhile and one spark plug was pulled. ...

Does that mean you haven't tried turning it over yet? Take all the spark plugs out and use a long screwdriver or something similar and place it length ways between two bolt heads holding the circulating pump pulley. You can turn the engine that way. It will at least tell you if it is seized or not.
 

Bob_VT

Moderator & Unofficial iBoats Historian
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26,019
I would not recommend trying to un-seize a motor until the drive has been disconnected AND if the motor is still locked up I would pull the head. I am not a fan of using oil or kero to loosen things unless the head is off. With the head removed it will give you a better idea of what the problem might be without forcing anything. If there is light rust from a ring I would want to clean it up before I rotated the motor and possibly scratch the bores.
 

UncleFluffy

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Nov 1, 2013
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16
Yes I do have a spare input shaft.....and I have a little 110V flux core welder. I did hook a battery up and tried to jump the starter...it engaged but the motor didn't spin....as for the outdrive....the prop spins in neutral and if I shift into fwd it ratchets clockwise and doesn't spin counter clockwise....in reverse it ratchets either way. The outdrive was replaced before I purchased it with a rebuilt unit as the dog clutch (clutch dog.....im not sure what is right) was screwed right up....I have all the extra parts from the old outdrive sitting in the boat.....I will try and pull the plugs and see about spinning it....I was hoping that I could put a wrench on the alternator pulley and spin it but the alternator just spins on the belt....Don't really wanna pull the drive but I have a feeling that I'm gonna have to.....I'll keep you guys posted....thanks for the quick responses thus far!
 

Fishermark

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...Don't really wanna pull the drive but I have a feeling that I'm gonna have to.....

Not only is it easy to pull, it is also necessary since this is a "new to you" boat. You need to evaluate the condition of the bellows, gimbal bearing, alignment, that kind of stuff. Regardless of what the previous owner has told you.
 

Bondo

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fair enough.....I'll pull the drive and see where I'm at after that......

Ayuh,..... Everything, but the prop shaft, turns with the crank shaft,....

yer test don't prove anything but the prop shaft is lockin' into gear,...
 

Bt Doctur

Supreme Mariner
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Aug 29, 2004
Messages
19,093
You need to understand how the system works by reading up on them from a good manual.Shift into full forward gear, remove the rams, the 6 nuts and pull straight back and off.
Take the old input shaft and weld a 2 foot section of pipe to the back of the yoke, weld a T section to the pipe to form the handel end, insert into coupler and spin motor.
 

Silvertip

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Sep 22, 2003
Messages
28,758
Don't do a "Hercules" on the bar in an attempt to turn the motor. A motor with no plugs in it (or with the head removed) will turn freely if not seized. If it is seized, cranking very hard can break ring lands and score cylinders which only costs more money. Be gentle and use a VERY slight rocking motion (back and forth). If the engine seems seized, do not try to break it free. Use whatever concoction you want to free things up. But patience is the key. Soak the cylinders and then walk away for a few days. I repeat. Walk away!. Then repeat the rocking motion. Still no luck? Soak again and walk away. Patience - remember? Eventually, you will feel a very slight movement of the crank. Now rock it back and forth again but DO NOT try a full rotation. Soak again and repeat the rocking motion. Each attempt should produce a little more rotation until you can make full rotation. With the head off you should also be able to see if and how much damage there is.
 

UncleFluffy

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Nov 1, 2013
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So an update.....my first thought was that because when I bought the boat, they had installed the recently rebuilt outdrive but didn't hook up the trim rams and had the drive tied up. I figured maybe it was up too high and the U-joint was binding causing the no crank issue. So I dropped the drive and tried again, no luck. Then I pulled the outdrive and checked everything out on the drive and it checks out and attempted to spin the motor over and no luck....so I've got the cylinders full of ATF/Kerosene and I will make my attempts to crank it over by hand assuming I can figure out something to get on the crank to spin it as my little 110 welder was not quite good enough to weld a pipe to it to try and crank from the back. On a positive note, my father-in-law who is a machinist is fabbing up an alignment bar for me with the specs I grabbed off of here so a big thanks for that. I should have that in the next week or so when they come out for thanksgiving. Also, the bellows are in great shape so that makes me happy but I'm pretty sure I still have some work cut out for me on this boat....but a winter project is exactly what I was looking for to keep me occupied so it will be ready (hopefully) for next spring when we go camping. It's still less of a project than my previous boat which makes me happy and for $400....not really complaining to much....thanks for all your help....if anybody has any other ideas on how to spin the motor over by hand, I'm all ears.

Cheers
 

UncleFluffy

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Nov 1, 2013
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So I got lucky....my input shaft still had the u-joints and gear bolted to it and I could get that in a bit and put a bar on the nut and try to spin the motor that way....hopefully i'll be able to get the motor to spin.....
 

achris

More fish than mountain goat
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May 19, 2004
Messages
27,468
So, you have the yoke and gear out of the drive. Do not, repeat DO NOT put them into the back of the engine to try and spin it as you suggested. The nut on the back of the gear is tightened to a specific torque, and that determines bearing pre-load. If you over tighten it, you'll increase the bearing pre-load and destroy the drive in very short order.

Also, you are going to need to put all that lot back in the drive and torque the retainer before you do anything else. That bearing/gear assembly should not have come out of the drive, unless you removed the retainer and pulled it out....

Chris....
 

UncleFluffy

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Nov 1, 2013
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Sorry....Allow me to reiterate......

My boat came with TWO outdrives.....one that was rebuilt and installed on the boat....the other was the old busted one with busted clutch dog and reverse gear teeth....the busted one was completely disassembled and in pieces in the boat......the input shaft and yoke that I am using is from the busted one NOT the good drive....the good drive is still in one piece and sitting comfortably in the corner of my shop.

sorry for the confusion ;)
 

UncleFluffy

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Nov 1, 2013
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it also means that I have a spare case that I could possibly build up from scratch if I should ever decide to do something like that
 

johnkom

Petty Officer 2nd Class
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Jul 26, 2004
Messages
163
We had an old "M" Farmall tractor on the farm that was seized from sitting for two years. We tried to pull it in high gear but the wheel just slid. So our old timer neighbor took all the spark plugs out. Poked around with a screw driver and determined which cylinder was on compression near the top of the stroke. He then took an old spark plug, busted out the insulator and welded a grease zerk onto it. Then with a regular farm sized grease gun started filling the cylinder with grease. Sure enough, after a little resistance the engine started rotating. He then stopped, put the other plugs in, removed the modified one and started the engine. Blew grease all over the place. But it started.
 
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achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
If the starter motor can't turn the engine over, I seriously doubt you on a spanner on the nut on the end of the yoke will be able to... If the engine IS that tight, I'd be pulling it out and stripping it down. That's more than a 'stuck ring'.....
 

UncleFluffy

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Joined
Nov 1, 2013
Messages
16
So if this motor turns out to be too far gone to corrosion or some other issue....my dad has a couple of old 250 engines from some Nova's sitting at his place he said I could have. Besides swapping the marine parts from the Mercruiser (starter, alternator, distributor, water pump, head, manifold and freeze plugs), is there anything else I would have to change over? Just trying to weigh my options before I plan my next move and with winter quickly approaching the great white north, I'd like to get a game plan established while I still have some warmth and time to do it.

Appreciate all the help guys.....really new the whole boat world in terms of repairs and what not and just not sure what I can and can't do.
 
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