Which is it, a long or short shaft Mercury?

mcgurk34 · #1 April 26th, 2004, 10:34 AM

I am helping a friend replace his blown lower unit on a 1993 115HP Mercury in-line 4 cyl. My friend asked if he should switch to a long shaft or stick with what he has now. Frankly, I don't know if he has a long or short shaft now. First question, How do you measure the shaft length? I need to know which type he has now to order the replacement. Second question, How do you determine which lower unit would be right for a given boat? Is there some rule of thumb for shaft length to match a boat?

Thanks,

Mcgurk

roscoe · #2 April 26th, 2004, 11:35 AM

THe shaft length is listed in the model number.

If you post it, someone can tell you, assuming he has the original lower unit on the motor.

Also look here: shaft length picture

mellowyellow · #3 April 26th, 2004, 11:36 AM

where motor bracket sits on transom to the anti-

ventalation/cavatation plate on L/U = current shaft

length.

mcgurk34 · #4 April 26th, 2004, 12:23 PM

Thanks for the responses. I won't be able to get to the boat before next weekend and I'll post the model number after that. I take it from both of the replies and looking at the diagram, that the normal shaft length should place the cavitation plate in-line with the bottom of the transom. Well, thats simple enough to measure. Thanks again.

McGurk