Short shaft/Long shaft/ transom height?

[Shawn Bertsch]

I have a boat, and an engine, but I am not sure that the engine will work. After measuring, it is apparent that the full circle of the rotating prop will be about 1/2 out of the water, but when the boat is in the water, will the prop be low enough to work?

Looking for some help as to ideal measurements of transom height and prop position before water displacement after boat is launched, or just some general tips and pointers! Thanks for the help!

 

[tashasdaddy]

Re: Short shaft/Long shaft/ transom height?

measure your transom from top where motor sits, to the bottom center. will either be in the 15 inch short shaft or 20 inch long shaft. the motors are measured from where they sit on the transom, to the flat plate just above the propeller. 15 inch is short shaft, 20 inch is long shaft, there are 25 and 30 inch inch shafts.

 

[Shawn Bertsch]

Re: Short shaft/Long shaft/ transom height?

so the transom height on the boat is 21", and the engine height is 17 from the bottom of the mount bracket to the flat plate directly above the prop. can I make it work or am I out of luck? my kicker transom height is 22", so i am assuming that it will work.

Also, how do i find what year the engine is? I am pretty sure it is mid to late 60's, possibly as late as mid 70's. It's a 35 hp 2 stroke Merc OB, Black with red and silver. Also, with a 1968 17' aluminum crestliner, what would be the max HP OB engine I should put on her? I can't find a data plate anywhere on the transom or anywhere else telling me a recommended HP rating for the boat.

Much appreciation for you help and advice.

 

[Seon]

Re: Short shaft/Long shaft/ transom height?

Simple measure the top of your transom to the bottom of your transom.
This measurement is your approximate shaft length.

If your measurement length is 15"-17", you need a short shaft
If your measurement length is 20"=22", you need a long shaft

 

[tashasdaddy]

Re: Short shaft/Long shaft/ transom height?

serial number of motor can date it at oldmercs.com it is a short shaft motor. those older motors were 2 inches longer than new motors, because of the water pump pick up. you can cut your transom down to accomodate the motor. that out enough in the center of the transom, so it has room to turn, then reseal,, it is a pretty good project. your boat was not required to have numbers on it. that did not come into effect until 1972.

 

[Shawn Bertsch]

Re: Short shaft/Long shaft/ transom height?

THANK YOU guys for replying.. but I am at the point where I think I should just go buy a long shaft motor..recommendations for a 1968 17'???? defenitelely don't want to rip the transom off by over powering the boat, but suggestions made to me were no largerthan a 115 HP...thoughts? suggestions?? goin 4 stroke for sure on the new one...

thanks for your feedback..

Shawn