what kind of motor, long or short shaft for my boat

johnnyo34 · Jun 28, 2009

I bought an older 14' Vanguard boat with a 40 hp 70ish motor that runs well. I had to replace the steering in it, so when I installed the steering cable kit the cable is too low to hook onto the motor.. My buddy came over & asked why the motor is not sitting right down on the transom, but is about 1 1/2" to 2 " , above the transom... If it was sitting right on the transom, the steering cable would hook right up.. It is screwed down there with the 2 tighteners, & there are 2 bolts down lower that go through the transom.. the boat measures 16" from top of transom to bottom of boat..
Should this boat have a long leg or short leg motor??? How can I tell if my motor has a long leg or short leg?? I guess green horns should not be buying boats..
thanks in advance..
John

esobofh · Jun 28, 2009

Re: what kind of motor, long or short shaft for my boat

Essentially, you need to measure the transom height;

with that measurement, here are general guidelines;

transom 15-17" - 15" (short shaft) outboard required.
transom 18-21" - 20" (long shaft) outboard required.
transom 21-27" - 25" (extra long shaft) outboard required.

This site is a great reference, with pictures:

http://www.smalloutboards.com/shaft.htm

johnnyo34 · Jun 28, 2009

Re: what kind of motor, long or short shaft for my boat

Thanks for your reply... from where the motor sitson the transom to the bottom of the boat measures 16", so I suspect I need a short shaft motor.. How can I tell if my existing motor is short shaft or long shaft?? If it is a long shaft, can I use the same motor & look for a short leg? would that work?
John

rockyrude · Jun 28, 2009

Re: what kind of motor, long or short shaft for my boat

The first question is, where is the anti-cav plate (the big plate just above the prop) is it even with the bottom of the boat? If it is more than 1" above the bottom, you can drop the motor to fit. If is already even with the bottom you can look for a short shaft intermediate housing but you will need a short shaft drive shaft and shift link.

esobofh · Jun 28, 2009

Re: what kind of motor, long or short shaft for my boat

That same website shows how/where to measure the outboard.

In short, from the underside of the transom mount (i.e. where the mount will contact the transom at the uppermost part) to the top of the cavitation plate is where you measure from.

Ideally, the cavitation plate is in-line with the bottom of your hull.

Some motors have long-shaft kits.. it consists of a lengthened leg, and a longer drive shaft. Or on some models, it's simply a 5" spacer, with a longer shaft. Consult your dealer.

johnnyo34 · Jun 28, 2009

Re: what kind of motor, long or short shaft for my boat

thanks for all your help.. It looks like the cavitation plate is almost even with the bottom of the boat.. I will go measure the leg of the motor now.. .. The motor is early seventies, & runs really well, so I hate to junk it.. would be nice to find a short leg if that's what is needed..
John

cheesegrits · Jun 28, 2009

Re: what kind of motor, long or short shaft for my boat

If it is a long shaft motor would it be possible to extend the top of the transom so the motor would fit? This seems like a much easier and cheaper way to fix your problem. Friend of mine extended his Aquasport 19-6 by 5 inches to fit his 08 140 Suzy. It worked great and he enjoys the taller transom in following seas. I don't know if a Vanguard is alum or fiberglass, but if its fiber that would make it real easy to extend it.

steelespike · Jun 28, 2009

Re: what kind of motor, long or short shaft for my boat

Just a point The anti vent(cavitation) plate even with the bottom is considered a starting point.Depending on the motor and boat the plate could end up an inch or more higher.The idea is to have as little motor in the water as possible while avoiding venting(cavitation) problems.
Dependiong on the steering bracket you may be able to buy or make an adapter to get the connection lower.

johnnyo34 · Jun 28, 2009

Re: what kind of motor, long or short shaft for my boat

I'm trying to attach a picture of the motor sitting on the transom. not quite accurate in the picture but it looks like the transom would have to be built up about 2".. don't know what to do about the checker plate. Any suggestions??

johnnyo34 · Jun 28, 2009

Re: what kind of motor, long or short shaft for my boat

steelespike said:
Just a point The anti vent(cavitation) plate even with the bottom is considered a starting point.Depending on the motor and boat the plate could end up an inch or more higher.The idea is to have as little motor in the water as possible while avoiding venting(cavitation) problems.
Dependiong on the steering bracket you may be able to buy or make an adapter to get the connection lower.

I'll try to get a couple more pics, close up of the steering bracket. The motor does work OK as is in the boat, but I can't get the steering hooked up as it sits. Is there any danger of maouvering the boat if it is left as high as it is, so long as the steering cable can be hooked up??? Oh & that plate looks like it might be just below the boat, not much, maybe 1/2" or so.
John

johnnyo34 · Jun 28, 2009

Re: what kind of motor, long or short shaft for my boat

the little angle iron with the rust around the hole is where the steering cable should be hooked up.. can a longer heavy piece of strap iron be used & bent so the bolt from the steering cable would go through. Should the steering cable be pretty much horizontal as it is, or can it be tilted up at more of an angle?
John

johnnyo34 · Jun 28, 2009

Re: what kind of motor, long or short shaft for my boat

Here is a more accurate picture of how the motor is sitting on the transom.

what kind of motor, long or short shaft for my boat

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