how can i find out what outboard motor shaft length is right for my boat

[basspro68]

is there some type of measurements i can do to make sure i get the right outboard motor shaft lenght.it had a 20 inch on it i was told but really dont know how to measure it period.ive sold the motor and was going to dowmgrade to what rating was on the boat which was a 175 thinking of going to a 175 or 150.need to know how to measure boat and motor too thanks.

 

[tmcalavy]

Re: how can i find out what outboard motor shaft length is right for my boat

Measure from top of transom, where motor will sit, to bottom of hull...that measurement should be same as from inside of transom clamp to cavitation plate (horizontal plate above gear case) on whatever outboard you choose.

 

[basspro68]

Re: how can i find out what outboard motor shaft length is right for my boat

hi thanks alot i love this site

 

[JB]

Re: how can i find out what outboard motor shaft length is right for my boat

If your transom is not perfectly vertical (few are) take that measurement on a vertical plane, BP, not against the surface of an angled transom.

 

[basspro68]

Re: how can i find out what outboard motor shaft length is right for my boat

ok---a little confused my bass boat has a very sloped transom---3 peice i would say---it goes from where motor bolts on to 14in---than to where aerator picks water up at--20-21 from top---than to where water drains out at bottom of boat around 30 from very top----all 3 different measurements slope inward towards front of boat what should i go by----i have a jackplate installed so i have adjustment.should i get a long shaft and adjust from there keeping gear foot below bottom of boat or how should i do it.

 

[jeeperman]

Re: how can i find out what outboard motor shaft length is right for my boat

Use a straight edge like a yard stick, etc. and place it up against the keel. Let it hangout back beyond the spot where the outboard would bolt-on.
Then measure straight up and down from the upper edge of transom down to the straight edge.