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1974 V6 OMC engine won't turn over

Z

zeek04877

New member
First First time here and of coarse it's with a problem so thanks in advance. I have a 1974 V6 Buick engine with a OMC stern drive. I parked the boat 7 years ago and haven't attempted to start the engine until a few weeks ago and the engine was locked up completely. I pulled the spark plugs and filled the cylinders with oil and let it set for a couple of weeks. Today I pulled the plugs and was able to turn the engine however it will only turn over about a half a revolution each way. When I reach this point I can hear a thud and the engine won't turn any further. I pulled the rocker covers and rocker shafts to verify that the valves weren't stuck down and they all are fully seated so I don't think the problem is in the engine but maybe something in the stern drive. Has anyone had or heard of this happening before? I can pull the stern drive off tomorrow and see if it will turn over then but would rather not if this isn't the problem. Again, thanks for any pointers you all may be able to offer.:(
 
OK, pulled the stern drive and turned the engine over with wrench and engine still only turned a half revolution and stopped. I kept turning back and forth until finely the engine went a little further and eventually went past whatever was restricting it. I kept turning the engine over for 20 or 30 revolutions however every time it reaches a certain point there is a rubbing/grating sound coming from the oil pan area, kind of like the crank or rods are rubbing against the bottom of the oil pan. Keep in mind this engine ran very well before it was parked 7 years ago. When pulling the dip stick it shows over full by a couple of inches over the full mark and the lower 4 inches of the stick is rusted/corroded. This makes me believe the oil pan may have water in it and after sitting for so long has possibly gathered rust or............. I think I will have to drain the oil and see what comes out and then possibly pull the pan and see what is in there. Also when I pulled the rocker covers and rocker shafts they were rusted as well.
Any ideas would be greatly appreciated. :confused:
Steve
 
Keep in mind this engine ran very well before it was parked 7 years ago. When pulling the dip stick it shows over full by a couple of inches over the full mark and the lower 4 inches of the stick is rusted/corroded. This makes me believe the oil pan may have water in it and after sitting for so long has possibly gathered rust or.............
Click to expand...

Ayuh,.... Either it wasn't winterized, or was poorly done, or there's been water runnin' into the throat of the carb for 7 years....

Whatever happened,.... It's Junk now...
 
Drain the oil pan put the plug back in, remove the battery from the boat, put the spark plugs back in. Fill the engine to the brim with kero or diesel fuel, let sit for a week or 2, drain the pan. remove the spark plugs, and try turning the engine by hand. Squirt wd 40 or pb blaster in the spark plug holes. Keep turning keep squirting and maybe you will break it loose.

I got a few started worse then yours.

You are a adult correct... i got to get into safety and draining out the kero or diesel from the bilge before you go and try to start the boat ?

I mean you are not going to try to blow your @zz up?

You want zero fumes and a bone dry bilge caphie ?

Post back when you have the conditions above exist ! We will go from there.
 
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Master mechanic said:
Drain the oil pan put the plug back in, remove the battery from the boat, put the spark plugs back in. Fill the engine to the brim with kero or diesel fuel, let sit for a week or 2, drain the pan. remove the spark plugs, and try turning the engine by hand. Squirt wd 40 or pb blaster in the spark plug holes. Keep turning keep squirting and maybe you will break it loose.

I got a few started worse then yours.

You are a adult correct... i got to get into safety and draining out the kero or diesel from the bilge before you go and try to start the boat ?

I mean you are not going to try to blow your @zz up?

You want zero fumes and a bone dry bilge caphie ?

Post back when you have the conditions above exist ! We will go from there.
Click to expand...

I would NOT squirt WD40 into the cylinders!!! It has a " cutting agent " in it, and will do more harm than help. Use the Diesel fuel, it will loosen things up better. Turn it over completely by hand (if you can ) a few times. Add another squirt of Diesel to each cylinder. Let sit.
After a few days to a week, drain the pan, re-fill with clean oil, get a fully charged battery and turn it over (just dont overheat the Starter) awhile. Leave plugs OUT.
After all that, see how loose it is. Depending on that, I would try to see if it fires. IF it starts, let it IDLE. DON'T rev it up on the garden hose !!!
I drove 800 miles round trip a few years ago to buy the same 225 Buick motor off a guy in New York State . It turned out he jipped me BAD, in that the engine had a rust score in one cylinder that was too far gone to even think of fixing. All I could salvage was all the tin, the heads, intake, etc. The block was scrap metal.

His name was Thorin Corliss, and I'd love to see him again !!! As it turns out, he had the REAL engine stashed somewhere else, and advertised it later. I saw this, e-mailed him....and of course, got NO response.

Good luck......
 
OK, removed the oil pan and discovered that the baffle that's bolted under the crank shaft was pushed up close enough to be in conflict with the rods during rotation. My guess is that this was the result of water in the oil pan and when the water froze it pushed the baffle up about one inch and was causing the noise during engine rotation. I have removed the baffle and straightened and am going to put all back together this weekend and see what happens. My question is.........when I took the rocker arms apart there is a shield (oil deflector) that is bolted on the top of the rocker arm on the starboard side and I can't remember if it goes on the front or the rear of the rocker arm (fore or aft). I think this shield is to keep oil from the vent pipe/tube. I can post picture if necessary. Thanks for your help with this mission. Steve
 
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