OMC Cobra upper pinion gear swap - elec shift parts, do they fit?

CamaroMan

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(apologies for posting this in the merc section - admins feel free to move)

Hi guys - I toasted an OMC upper last week due to idiocy on my part by not waiting for the oil to settle and bubbles to come up (my 1st time doing an omc). Filled it up to dipstick and thought it was good.

Anyway - I am looking for an upper gear/pinion set 21/19.. Im wondering if the elec shift parts are the same? a guy on CL sells this stuff regularly and he has a elec shift upper gear set for sale..

Will the elec ring/pinion be the same/fit?



Also - any special tools needed for the swap? Im familiar with backlash,wear patterns etc.. just wondering if theres a definitive special tool required or If i can manage without them.. thanks. Dont have a problem pressing bearings on etc..
 
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Lou C

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I would doubt it because while the lower units between the stringer and the Cobra are similar the upper gear housings are totally different. Take a look at BRPs online parts catalog and compare parts #s....
 

Scott Danforth

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electric shift is old tech, mid 70's and earlier. Cobra is newer tech, 86 and later other than OMC on the name, one is an apple, one is a carrot
 

HT32BSX115

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looking for an upper gear/pinion set 21/19.. Im wondering if the elec shift parts are the same? a guy on CL sells this stuff regularly and he has a elec shift upper gear set for sale..

Will the elec ring/pinion be the same/fit?

Howdy,

If the actual part numbers are identical, then yes.

Go to http://epc.brp.com select your model and jot down the part numbers for the upper gearsets and compare to earlier stringer models. I am willing to bet that they're not even similar. (a quick comparison with the 1987 and 1986 models indicates they're not)


waiting for the oil to settle and bubbles to come up (my 1st time doing an omc). Filled it up to dipstick and thought it was good.
Please don't take this as trying to "beat you up on what you did" but your above description indicates that you maybe didn't just NOT wait for the bubbles to "come up". There's nothing in OMC Cobra service manual that suggests you should wait for bubbles to do anything.

If you fill it wrong, you absolutely trap a bubble(s) in the drive that will uncover the upper gears when the oil warms and thins out under load.

If you fill it (IAW the OMC manual) from the "FILL" port, to "FULL" with the dipstick "resting" on top of the threads allowing for a slight overfill" (OMC's words) there will be no bubble you have to wait for..

It also really sounds like you may have filled it from the drain port......OR, you didn't unscrew the dipstick so that you would fill it while it was resting on top of the threads.

Again, I am not trying to hammer what you did. (You feel bad enough as it is I am sure!) But I want everyone else who reads this thread to know that there is only one safe, OMC approved way to fill a Dog Clutch Cobra.

I know there are people out there that have gotten away with doing it differently. but there is no procedure that includes waiting for the bubbles to come to the top. (although I guess you could say that slightly overfilling it does essentially that......... you just don't have to wait for it)

I am really sorry this happened to you . (My previous King Cobra was replaced TWICE by 2 different "Dealers" who filled it wrong....luckily they replaced the drive both times without any "Lawyering-up"!!.......there was some threatening though)


OTOH, This might be a good time to consider getting an SEI drive conversion unless you can find a used replacement Cobra

You will need to completely disassemble BOTH the upper and lower to inspect and flush. The oil from the destroyed upper circulated metal debris into the lower. It's essentially a complete rebuild now. (upper and lower) A complete rebuild could cost nearly as much or more than just replacing with an SEI + adapter kit....

Also - any special tools needed for the swap?
I sold my OMC service manual with the drive when I pulled it all. I seem to remember several "special" tools required for a rebuild. But you could probably make some of them........ It's somewhat more complicated than rebuilding a rear-end but probably not "Rocket Science"

You can look at http://boatinfo.no/lib/omc/manuals/1986-1998omcmanual.html#/488 to see some stuff on the Cobra(s)

It would be best to get the OEM OMC manual. I wouldn't use an after market manual like Seloc/Clymer though. Too many errors.

Regards,

Rick
 

Lou C

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I believe Sierra makes gears for OMC Cobras, if the OE is not available any longer. I spoke with the guys over at Crowley Marine in Colorado. They sell OE OMC, Evinrude, Mercury, Mercruiser and Yamaha parts. They sell what they refer to as NEW..... Cobra lower & upper gear housings as well as complete drives. Of course they are expensive, like double the price of an SEI for the whole drive. When I spoke with them, I specifically asked if they use GLM parts in the remans and they said no, and I asked how to they get the parts that BRP no longer sells? And they said, they have an US sourced fab and machine shop that makes them....hmmm....well if its true, that's good if you want a good rebuilt unit. As far as an SEI conversion, I think the idea is very clever, and creative thinking went into it. Just heard too much about failures and bad paint quality, etc. However, there seems to be no reason why, you could not simply use their kit and use a Merc drive, rebuilt instead of the SEI. Yes it costs more but what's your time worth? I hate fixing the same thing more than once.

http://www.crowleymarine.com/support...-articles.html
http://www.crowleymarine.com/support...t-filling.html
 

CamaroMan

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hey guys thanks for that..

HT32BSX115 - all good! Sorry for writing it so backwards.. on mercs I usually squeeze the oil thru the top vent hole till it comes out (now i realize this is bad practice!). I did the same with the OMC thru dipstick hole :0 - i noticed bubbles coming up thru the drive shaft from the bottom when i poured gas down to verify how much it needs (and flush out some debris)..

From now ill do what the darn manual says even oil fills!

There are many companies that re-machine gears, its quite a common practice. Since mine were super bad im busy looking at finding someone who might be able to refurbish the ones i toasted..

Yes the gear prices outweigh the costs - I found a good used freshwater complete system for a steal, but the gearing is different :/ it has 21:17 and I need 21:19 upper..
 

Scott Danforth

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And they said, they have an US sourced fab and machine shop that makes them....hmmm....well if its true, that's good i

Its a machine shop in SE Wisconsin. I have purchased stringer parts direct from them about 15 years ago. they were the machine shop that OMC used to use to make shafts, gears, etc. they used to advertise on Ebay, however now have a lot of OMC work thru Crowley, and a few others.
 

Lou C

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Thanks for that Scott, if I ever need one, at least I can feel as if it will hold up as well as the originals, which were good as long as you maintained the shift cable adjustment.
 

CamaroMan

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found a complete upper gear set for 350. will press them in 2moro. I noticed paper (shims?) on the upper.. like 5 pieces, 3 reen and 2 pink - what do they do?
 
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