Long shaft on a short shaft transom...problem or no?

A

alcock lake

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Joined
Aug 2, 2007
Messages
8
Hi; I just got a great deal on an 1987 Mercury 9.9 long shaft, I was looking for a short shaft but it was not to be!
My concern is about running the long shaft on a 14ft Lund designed for a short shaft. The boat will currently plane with 2 people in it and fishing gear using the current 1982 Johnson 9.9; will it do the same with the long shaft Merc?
I bought the Merc as a "back-up" engine for my cottage rental business, in case one of the clients damages the primary motor I can drop the Merc on the transom.....seemed like a good idea or have I made a big boo boo?
 
wbeaton

wbeaton

Commander
Joined
Jul 30, 2006
Messages
2,332
Re: Long shaft on a short shaft transom...problem or no?

It won't hurt anything. It'll have more drag so performance may decrease. What is wrong with the old Johnson?
 
Silvertip

Silvertip

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Joined
Sep 22, 2003
Messages
28,762
Re: Long shaft on a short shaft transom...problem or no?

Because the lower unit will extend so far below the bottom of the boat, the bow rise under hard acceleration may be higher than you had before, especially with just you in the boat. It may also have some high speed turning quirks that might take getting used to. Be very careful when making very short high speed turns.
 
tashasdaddy

tashasdaddy

Honorary Moderator Emeritus
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Nov 11, 2005
Messages
51,019
Re: Long shaft on a short shaft transom...problem or no?

why not just build yourself a small jackplate to raise the motor. either have some aluminum bent or that some aluminum angle bolt 2 pieces together to make a modified Z for each side. and some exterior plywood. this one has had a 50hp and 40 hp on it. cost of aluminum and bending was $50.00




 
A

alcock lake

Cadet
Joined
Aug 2, 2007
Messages
8
Re: Long shaft on a short shaft transom...problem or no?

There is nothing wrong with the old Johnson...I just needed a second motor as a back-up in case it goes out of service for a period if a client damages it. I had hoped to find another short shaft but couldn't and came up with the Merc for a good price ($380).
I'll post a pic of the boat and the Johnson but I don't have a pic yet of the Merc long shaft.
 

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tashasdaddy

tashasdaddy

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51,019
Re: Long shaft on a short shaft transom...problem or no?

client damages it. i f you are renting, i highly recommend using the jack plate, as someone may say the boat had the wrong set up, using the long shaft. this could be a liability problem in and accident.

say they hit a submerged object, and someone was injured, then they say, that the motor was deeper than it need to be, if it was the right depth, we would not have it the object.
 
kenmyfam

kenmyfam

Supreme Mariner
Joined
Aug 10, 2006
Messages
14,385
Re: Long shaft on a short shaft transom...problem or no?

TD has an excellent point with the liability thing. I would raise it up or try to trade for a short shaft motor.
 
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