I'm reposting this question here as per a suggestion from another member. Any help would be greatly appreciated!
Originally Posted by Lou C
That's an OMC Cobra drive with the Chevy 4.3 V-6, same power package I have in mine. I have the 4bbl carb, with that the WOT rpm is supposed to be 4400-4800. if it has the 2bbl it's supposed to be 4200-4600.
These drives are not the ones built as a joint venture with Volvo, they are the last of the pure OMC dog clutch Cobras. There are a couple of things you have to know about them, one is they are fussy about the cable adjustment, so if it jumps out of gear, or doesn't come out of gear, you have to get it fixed right away or the drive can be damaged. The other important point is that the procedure for filling them with gear oil is different than a Merc, you have to drain from the bottom drain on the lower unit, but the fill plug is the next screw up near the joint between the upper and lower unit. You drain it with the dipstick in the top cap (flat plate on top of drive) removed, so it drains. Then replace the drain plug at the bottom of the lower unit. Next rest the dipstick in the hole in the top plate but do not screw in, that allows air to escape and helps avoid an air bubble. You hook your gear oil pump to the fill plug hole that is near the joint between the upper and lower units. You need to get about 2 qts of gear oil in there. Check the dipstick, once it reads full you screw it in, and then quickly remove the gear oil pump and replace the fill plug. Now remove the dipstick and check it again, if low add a little through the dipstick hole. Here are some pix to to make it a little more clear. Whatever you do, DO NOT remove the large screw under the OMC Cobra medallion on the side of the upper unit, the retainer for the screw will fall in the upper unit and you will have to remove the drive to get it out!
Also on the Crowley Marine website, if you look in product support, under OMC drives, it has the procedure from the factory manual for the gear oil change and R&Ring the drive. At this point when you winterize it you should R & R the drive to check the bellows, gimble and ujionts. Note that the pic on the left, has the 3 water drain plugs you have to remove to let the pivot housing drain when winterizing. The pic on the right shows the fill and drain plugs for the gear oil. You can use Merc High Performance gear lube if you cant' find the OMC Hi Vis or HPF gear lube.
www.crowleymarine.com
Lou, I was getting ready to tear into this project and I have a question.
I think it was in one of my service manuals, or it may have just been from an old boat mechanic. Where ever the information came from, this is what I was told:
When doing the fluids in the out-drive, I need to remove both plugs and the top dipstick.
Then, I fill from the bottom plug until fluid comes out through the middle plug (also called the fill plug)
Once fluid comes out of the middle plug, I replace the bottom drain plug.
I then leave the dipstick resting on the threads (not seal so air can escape). I then fill through the middle plug until the oil level is on the right spot on the dipstick. Then replace the middle plug and tighten down the dipstick.
Now, what I'm reading with your instructions is that I remove the plugs, then put in the bottom drain plug and fill only through the middle plug until it reads correctly on the dipstick.
I just want to make 100% certain I do this correctly and do not trap any air in the drive. At face value, it seems silly to fill from the bottom and then fill again from the middle, but I also understand that these things are finicky and this may be the only way to get all of the air out of the system.
Any other OMC owners care to chime in with opinions or experience?
Regards,
Mike
Originally Posted by Lou C
That's an OMC Cobra drive with the Chevy 4.3 V-6, same power package I have in mine. I have the 4bbl carb, with that the WOT rpm is supposed to be 4400-4800. if it has the 2bbl it's supposed to be 4200-4600.
These drives are not the ones built as a joint venture with Volvo, they are the last of the pure OMC dog clutch Cobras. There are a couple of things you have to know about them, one is they are fussy about the cable adjustment, so if it jumps out of gear, or doesn't come out of gear, you have to get it fixed right away or the drive can be damaged. The other important point is that the procedure for filling them with gear oil is different than a Merc, you have to drain from the bottom drain on the lower unit, but the fill plug is the next screw up near the joint between the upper and lower unit. You drain it with the dipstick in the top cap (flat plate on top of drive) removed, so it drains. Then replace the drain plug at the bottom of the lower unit. Next rest the dipstick in the hole in the top plate but do not screw in, that allows air to escape and helps avoid an air bubble. You hook your gear oil pump to the fill plug hole that is near the joint between the upper and lower units. You need to get about 2 qts of gear oil in there. Check the dipstick, once it reads full you screw it in, and then quickly remove the gear oil pump and replace the fill plug. Now remove the dipstick and check it again, if low add a little through the dipstick hole. Here are some pix to to make it a little more clear. Whatever you do, DO NOT remove the large screw under the OMC Cobra medallion on the side of the upper unit, the retainer for the screw will fall in the upper unit and you will have to remove the drive to get it out!
Also on the Crowley Marine website, if you look in product support, under OMC drives, it has the procedure from the factory manual for the gear oil change and R&Ring the drive. At this point when you winterize it you should R & R the drive to check the bellows, gimble and ujionts. Note that the pic on the left, has the 3 water drain plugs you have to remove to let the pivot housing drain when winterizing. The pic on the right shows the fill and drain plugs for the gear oil. You can use Merc High Performance gear lube if you cant' find the OMC Hi Vis or HPF gear lube.
www.crowleymarine.com
Lou, I was getting ready to tear into this project and I have a question.
I think it was in one of my service manuals, or it may have just been from an old boat mechanic. Where ever the information came from, this is what I was told:
When doing the fluids in the out-drive, I need to remove both plugs and the top dipstick.
Then, I fill from the bottom plug until fluid comes out through the middle plug (also called the fill plug)
Once fluid comes out of the middle plug, I replace the bottom drain plug.
I then leave the dipstick resting on the threads (not seal so air can escape). I then fill through the middle plug until the oil level is on the right spot on the dipstick. Then replace the middle plug and tighten down the dipstick.
Now, what I'm reading with your instructions is that I remove the plugs, then put in the bottom drain plug and fill only through the middle plug until it reads correctly on the dipstick.
I just want to make 100% certain I do this correctly and do not trap any air in the drive. At face value, it seems silly to fill from the bottom and then fill again from the middle, but I also understand that these things are finicky and this may be the only way to get all of the air out of the system.
Any other OMC owners care to chime in with opinions or experience?
Regards,
Mike
