Damaged OMC 140hp Upper Gearbox Case

[wongsta]

Good Morning all,
I have a damaged gearbox case (upper section) from a OMC 140hp...I did some research and the part no. seems to be 980805 (but coming up as obselete ))...does anyone know if it can be repaired, or if i can get one Used; or even some ideas what could be used as substitute?

 

[VE8EV]

It likely can't be repaired but it is available new. Google "GLM 27000". Used ones can also be found (eBay). The housing is the same from 1973-85 but the gear ratios are different for each size engine. Your 140hp would require the 21:18 gears if you were looking at a complete upper. If your existing bearings and gears are ok they're not too difficult to swap from one gearcase to another.

 

[wongsta]

Thanks much will look into that...somebody was telling me that the 21/18 gear ratio would work for the newer 4 cylinders and that I should get the 19/20 ratio so not quite sure what is right with that

 

[VE8EV]

Depending on which prop you're running now you can sometimes go up or down on the gear ratio by 1 (like a 21:18 to a 21:19) and just change prop pitch if necessary to keep your WOT RPM in the recommended range.

 

[wongsta]

Ok sounds good so basically the only thing I would I have to worry about is prop specs if I get aone with newer ratio ie 21/18...if that's the case what is the specs of the prop I need to source if I go that route?

 

[VE8EV]

It all depends on what you're running now. If you go with a higher ratio then you'll (maybe) need to compensate with a higher pitch prop. For example, if you have a 14 pitch prop now and you replace your 21:18 drive with a 21:19 you might need to switch to a 16 pitch prop. You really have to put it on the water first to see how it works for you.

 

[wongsta]

ok thanks much. i actually sourced a used casing (upper) that i am planning to transfer the internals to from the broken one, hoping that everything inside is okay.i also ordered a seal kits and shims...Is there anything I need to pay extra care with when transferring parts?Or any tricks of the trade?lol

 

[VE8EV]

I always put a generous amount of grease on the o-rings when it goes together. There's some detailed pictures on YouTube of the assembly process, search for Wayne Coll.

 

[wongsta]

Okay will do thanks