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convert long shaft to short shaft or .. ?

Posted: Sun Mar 02, 2008 3:54 pm
by madog99
Well , the season is underway , picked up a 15hp Johnson today ,'98 2s for our 14.5ft fiberglass boat . Problem is it's a long shaft and the transom is for a shortshaft . It's the standard FB boat you see around , with a litle bit of a covered bow , tiller model . So have 2 choices , buy the little braket to mount the long shaft ( $160 locally ) , install that and bob's your uncle (or so they say ?) This would require drilling holes etc .

2and choice would be to convert the motor to short shaft . Looking at it it seems that the extension should just unbolt but can't be that simple can it ? There is a drive shaft of course .
Any ideas as to what that would cost to have done ?

And one more question for the motor savy , what's a complete service and tune up running at a dealer these days ? Figure to take it in and get the complete check up done , start off on the right foot .
thanks
John

it's easy

Posted: Tue Mar 04, 2008 9:34 am
by mikemicropterus
:D All you have to do is hit your easy button....

Maintenance check 1 hr plus parts, labor rate 65/hr

Make into short shaft, need drive shaft. The exhaust tube does not have to be replaced but the water pump tube need s to be shortened by cutting it or buying a new one.
I have done lots of these, I have a 15 hp evinrude that puts out 25hp...
I have some spare parts but I'll look for a driveshaft, not sure whether I have one... :D

Posted: Thu Mar 06, 2008 5:53 pm
by madog99
Mike , thanks for the info !

3rd Option

Posted: Fri Mar 07, 2008 3:38 pm
by hatterharry
There is nothing inherently illegal or unsafe to run a long shaft motor on a short shaft transom; search the net and you will find this to be the case.

Of course, it would cause some extra drag and you would have to be very careful in certain shallow water situations, but I know many people who do this with great success.

Posted: Fri Mar 07, 2008 3:54 pm
by JP
One thing to consider if you run a long shaft on a short shaft boat you will have a real hard time getting on plain. Because the cavitation plate will sit 4" bellow the hull there will be no lift and thus take forever to get on plain.

JP

not illeagl but unsafe

Posted: Fri Mar 07, 2008 4:11 pm
by mikemicropterus
:D I wouldn't say illeagl but I would say unsafe as the leverage factor of too much skeg in the water does affect the stability of the boat...
It will lead to lower performance and the boat will not run at the proper attitude with respect to the water surface..... proper angle of attack cannot be achieved.....too much drag and boat cannot be lifted out of water easily but it will still plane.....

....the cavitationplate will cause lift as would any plane being pushed through the water that's what a doelplhin is for..... now it maybe decreased by the amount of lower unit below surface but it will still cause the motor to lift....

Posted: Mon Mar 10, 2008 5:19 pm
by madog99
Thanks for the input boy's . Guess we are going with the mini jacker plate to raise the motor. Seems to be the most feasible method , plus on the trailer now with a short shaft there is only a few inches clearance for the skeg , so add 5" and first bump skeg is gone . Now get an ice breaker prow on the boat and will be set for april !

Posted: Mon Mar 10, 2008 9:26 pm
by jiggy2006
madog.. check your pm and get in touch with that guy. you can get away by getting a short shaft lower unit and install it, very easy to do.