I recently had an OMC lower unit rebuilt. Unfortunatley it has gone out a second time. The way is goes out, is when you are driving across the water it simply quits propelling. It acts as if it jumps out of gear, no noise no bumps, just a simple clicking of the drive slowing down. Due to the fact, I think, no force being applied. My question is: Can I convert this to another drive? Or is there another way that I am not thinking of to get away from a problematic drive system?
The Boat Design & Boatbuilding Site
omc problems
- Thread starter double00
- Start date
I take it this is an older Cobra drive?
A few questions. Does the motor over-rev when this happens, or does the motor drag down too? What's the engine, prop and gear ratio?
The Cobra has its problems; so does every other sterndrive. Yours may be a bit more of a lemon than most. But I've seen Cobras go 20 years without trouble, so I wouldn't go blaming the drive right away. Going out so soon after a rebuild could mean the shop screwed up. Tolerances inside the lower unit are unbelievably tight; in some legs (the Merc SportMaster, for isntance) the tolerances are tighter than those on the innards of the engine itself. If the shop didn't get it exactly right on the rebuild this could explain your problem.
A few questions. Does the motor over-rev when this happens, or does the motor drag down too? What's the engine, prop and gear ratio?
The Cobra has its problems; so does every other sterndrive. Yours may be a bit more of a lemon than most. But I've seen Cobras go 20 years without trouble, so I wouldn't go blaming the drive right away. Going out so soon after a rebuild could mean the shop screwed up. Tolerances inside the lower unit are unbelievably tight; in some legs (the Merc SportMaster, for isntance) the tolerances are tighter than those on the innards of the engine itself. If the shop didn't get it exactly right on the rebuild this could explain your problem.
Thanks, for you reply. What can I do from this point. I don't think I can prove the shop screwed up. It has been in business for years, and I don't have a clue as how. Do you have any ideas as to what road I can take from here. It is on a 82' Ranger bass/ski comb. Not many seen, but I have one. Anything you can suggest will be greatly appreciated.
I'll have to assume you have a Cobra with either a 4.3 or 5.0 L engine. For starters, your drive is 23 years old. My suspicion is it is indeed slipping out of gear. You could confirm this is the case if the motor over-revs when this happens. Your drive probably has a hydraulically actuated clutch dog and so the solution could be as simple as changing the drive oil. Or the lower end may have to be taken off and the shift linkage adjusted and fluid lines cleaned. (This should have been done when the unit was rebuilt.)
If you want a different drive, that's possible, but would be on the order of $2,000 and up for a rebuilt Alpha, or more if you want a better drive or a brand-new unit.
If you want a different drive, that's possible, but would be on the order of $2,000 and up for a rebuilt Alpha, or more if you want a better drive or a brand-new unit.
The motor did rev up when it went out the first time. However, my brother had borrowed it on the 2nd time. I assume it did. I, unfortnately do not have the manual with me it is at my lake house with the boat. So I can not confirm whether or not it has a hydraulically actuated clutch dog. In reading I can not remember that specifically. It makes sense, knowing if water got in the fluid this could cause it to "slip out of gear" especially if it were hydraulically activated. I would only have to change the fluid to test that. Is there any specs on the exact shift linkage?
I have confirmed from my father, he went to get the manual. The only thing he can find in the manual as to the model or series; it is a 800 series. Would this be in order
as the style you are refering to. I am asking this because this is the first OMC (and last) I have ever owned. I have always had Mercruisers with 0 problems. Lucky I guess.
as the style you are refering to. I am asking this because this is the first OMC (and last) I have ever owned. I have always had Mercruisers with 0 problems. Lucky I guess.
KCAztec73
Junior Member
Omc 800
Old OMC drives were given the numbers 400/800 based on the engine they were hooked up to. 400 was for 4/6 cyl and the 800 was for 8 cyl. From what I understand they stopped this numbering when they switched to the Cobras which leads me to believe you may have a stringer style driver. Do you by chance have a photo of the drive? As far as switching out the drive. If it is indeed a stringer drive a switch to a merc would require a rework of the transom as the hole is much larger for the OMC than for the merc. I have a stringer drive and have contemplated the same thing. My drive is a '73 and has been rebuilt once. There are many places that sell new lower units, upper units and intermediate housings. Here is a link to one such company
http://www.sterndrive.info/
They have parts for all OMC drivers stringer and cobra. Hope this helps.
Old OMC drives were given the numbers 400/800 based on the engine they were hooked up to. 400 was for 4/6 cyl and the 800 was for 8 cyl. From what I understand they stopped this numbering when they switched to the Cobras which leads me to believe you may have a stringer style driver. Do you by chance have a photo of the drive? As far as switching out the drive. If it is indeed a stringer drive a switch to a merc would require a rework of the transom as the hole is much larger for the OMC than for the merc. I have a stringer drive and have contemplated the same thing. My drive is a '73 and has been rebuilt once. There are many places that sell new lower units, upper units and intermediate housings. Here is a link to one such company
http://www.sterndrive.info/
They have parts for all OMC drivers stringer and cobra. Hope this helps.
xchsurfers
New Member
chevy 4.3ltr problems
Chevy 4.3 ltr V6 Petrol
Running problems:
removed spark plugs and found water on three of them all on the same side. spun engine over and a lot of water came out of one cylinder.I replaced the exhaust manifolds approx 18mths ago.
Could it be head gasket ?? or something more sinister,water has got into the oil.
please help
Chevy 4.3 ltr V6 Petrol
Running problems:
removed spark plugs and found water on three of them all on the same side. spun engine over and a lot of water came out of one cylinder.I replaced the exhaust manifolds approx 18mths ago.
Could it be head gasket ?? or something more sinister,water has got into the oil.
please help
Could be a number of things but first answer a few questions:
-did this occur mid season or first run after winterization?
-what is the compression in each cylinder? And mark it on a diagram of the engine
-Did you properly torque the new manifold and or re-torque it after putting some hours on it?
-Do you notice strange water coming off the engine or manifolds in the bilge after running and testing in your driveway?
Sounds like a blown head gasket but improper winterization issues leading to craked heads and blocks due to residual water expansion, can in the worst case senario be the actual culprit.
Get all the water out ASAP and get some fogging oil in those cylinders. Moisture and raw scored steel is a very very bad thing. WD-40 or just some 40wt on a scotchbrite rubbed on the cylinder walls can save the rest of the engine.
-did this occur mid season or first run after winterization?
-what is the compression in each cylinder? And mark it on a diagram of the engine
-Did you properly torque the new manifold and or re-torque it after putting some hours on it?
-Do you notice strange water coming off the engine or manifolds in the bilge after running and testing in your driveway?
Sounds like a blown head gasket but improper winterization issues leading to craked heads and blocks due to residual water expansion, can in the worst case senario be the actual culprit.
Get all the water out ASAP and get some fogging oil in those cylinders. Moisture and raw scored steel is a very very bad thing. WD-40 or just some 40wt on a scotchbrite rubbed on the cylinder walls can save the rest of the engine.
email is jimmycalvert@comcast.net
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