Which part #s are these bell housing to stern drive lock nuts?

I

ispaydeu

Seaman Apprentice
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Apr 6, 2010
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For a 1978 boat with a 165 HP mercruiser engine / stern drive. Alpha 1 / Gen 1

I had a "brain fart" when winterizing... I took off my sterndrive and brought it indoors so that way I wouldn't have to worry about winterizing it. In doing this, I misplaced the 6 bolts that attach the stern drive to the bell housing...

If my memory serves me correctly, they use a 5/8" wrench / ratchet to remove them... Its the 6 nuts that are at the top of the sterndrive that attach the stern drive to the bell housing / transom.

Does anyone know which part # those are? I found a locknut area on iboats.com, but not certain which one it is.

Also, does it really matter if I buy them from a marina place? Could I just go to my local home improvement store? If I CAN, then does anyone know the correct size and thread size that I would need to purchase?
 
Eric 3.7LX Alpha 1

Eric 3.7LX Alpha 1

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Re: Which part #s are these bell housing to stern drive lock nuts?

You can buy them anywhere, but, they have to be stanless and a lock nut, not a regular nut. Probably not gonna have. You should be replacing them anyways the locknuts get worn out after so many uses.

Probably easier to get the correct marine ones.

7/16-20 Threads
 
Don S

Don S

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Re: Which part #s are these bell housing to stern drive lock nuts?

I would advise getting the proper nuts from a dealer, or online. Those nuts are not stainless, they are chrome plated brass. The reason stainless is not used is to prevent galling of the threads.
 
Eric 3.7LX Alpha 1

Eric 3.7LX Alpha 1

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Re: Which part #s are these bell housing to stern drive lock nuts?

So I did a quick search on it and here is what I found:

The most likely cause of this condition is thread ?galling? or seizing. Galling can result from surface oxidation in some materials. When the parts are engaged, microscopic particles break loose from the roughened surfaces and lodge between the mating parts. This results in mated parts ?sticking? together and is responsible for ?galling?. Thread galling can become severe enough that the mating parts seize, making it virtually impossible to separate them. :eek: Galling is a genuine problem which should be considered in design. Galling can best be avoided by manufacturing mating parts of different materials and hardnesses.

Learned something new today. :D Man that would make a usually easy job into :facepalm:
 
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