25'' motor on a 20'' transom

[starcraftlegasea]

I was looking to see if it is that big of deal to put a 25'' motor on a 20'' transom. I have a good deal on the motor, but I also don't want to break anything on my boat. Can someone give me advice. Thanks

 

[bassboy1]

Re: 25'' motor on a 20'' transom

The only thing is, it provides more drag, and may splash water droplets into the splashwell. It can be solved with a moveable jackplate, or a fixed jackplate. Or you could make a new transom, an modify it to make it taller.

 

[iwombat]

Re: 25'' motor on a 20'' transom

It's also going to be a lot harder to steer. If you've got any turbulence on the keel of your boat expect it to pull hard to one side or the other.

 

[Chris1956]

Re: 25'' motor on a 20'' transom

I ran my '58 Fat-Fifty (20" shaft) on my 14' runabout with a 15" transom. It dragged a bit, but I did not have any steeering issues and it never ventilated!

If you could build up your transom 2 inches or so, it would be a good idea.

 

[JB]

Re: 25'' motor on a 20'' transom

Moving to non-repair outboard

 

[steelespike]

Re: 25'' motor on a 20'' transom

Certainly not an efficient way to operate your boat.1 inch up or down could mean 2 to 3 mph.Of course 5 inches isn't likely to eat 15 mph but it is going to eat some gas.A jack plate would surely help.

 

[Dhadley]

Re: 25'' motor on a 20'' transom

Just use a manual jackplate. It's done all the time, no big deal. Most have 5 to 6" height adjustment so you're all set. Kinda common.

 

[Texasmark]

Re: 25'' motor on a 20'' transom

Not hijacking the thread, but Chris, did you beef up the transom?

I had a friend that bought a 60 hp Rude Sportifour (I think is the correct name) back in the '60's and put it on his 14' home brew hull. First time he goosed it he had to fish the engine out of the drink. Was funny to us........ not him obviously.
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Other problem too, if you don't jack it up is that your prop is 5" lower in the water making shallow water operation, normally encountered with smaller boats, more difficult.

Mark