what length shaft do I need??

[IGKNIGHTED]

Hello, I blew a piston in my Black Max 135 so I'm looking for a used motor but I'm not sure what size shaft I need.

I'm putting it on my 1992 Checkmate 17' bow rider.

Are 20" shafts for bass boats and 25" for sport boats?

Thanks for the help!

 

[LORDY611]

Re: what length shaft do I need??

I have a "long shaft" that is on a boat with a 20" transom. Measure from the top of the mount, where it rests on the transom to the cavitation plate. Mine measures 20" like the transom. A good place to start is having the cavitation plate even with the bottom of the hull. Fine-tuning may need to be done before you get top performance by raising the motor a bit.

 

[emckelvy]

Re: what length shaft do I need??

20" is "LS" or Long Shaft.

25" is "XLS" or Extra Long Shaft. XLS gives a lot of freeboard which is nice for fishing boats etc.

You typically wouldn't find a deep transom on a smaller hi-po boat, but transom height is not necessarily dictated by style of boat. Depends a lot on the mfr too.

For most applications, having the anti-ventilation plate 3/4" to 1" above the level of the keel will give good performance. Much more than that you're talking hi-po props and careful setup.

Later-model motors have lots of bolts holes in the mounting pattern, so you have plenty of leeway in height adjustment.

HTH & Happy Motor Hunting (P.S. If you're looking for a new motor, E-Techs are Da Bomb nowadays!!!)