New motor sits too high

[huntin dawg]

Hey Folks,
I just repowered my 14 ft aluminum fishing boat with a Merc 20 HP 4-stroke. This boat has had the transom rebuilt. Smoker Craft recommended a short shaft motor so that's what I bought. However, now I wonder if the transom was built higher because this is how my motor sits.



This is how I had to trim the motor to get it to run worth a darn. I got 15 MPH out of it.



Suggestions? Cut the transom down?

Thanks,
Jason

 

[Maclin]

Re: New motor sits too high

Jack plate? Not sure if they allow as much movement as you need, they might.

 

[steelespike]

Re: New motor sits too high

The gear case seems like its a long ways from the boat. The boat seems like the bottom has an abrupt curve downward at he keel' and the rest of the bottom seems at a reasonable height.
If its just clamped on just try sliding the motor over an inch or 2 temporarily to maybe clear some of that abrupt deep keel.
Problem with the jack plate, when lowering a motor, is clearance for the the clamp handles
and of course clearance for the tiller and powerhead pan.

 

[JimS123]

Re: New motor sits too high

The pictures are at an angle that its hard to tell what you got. From the symptoms it sounds like too much HP and / or too much weight. What is the distance between the top of the transom and the bottom of the boat? to the bottom of the keel?

This could be a classic application for a hydrofoil.

 

[huntin dawg]

Re: New motor sits too high

Here's another angle. The boat has a pretty good keel on it.



The transom also has a pretty steep angle on it which is why the lower end is so far from the transom.
I think I'm going to have to alter the transom to lower the motor.

Do you think a hydrofoil will help so I don't have to rebuild the transom??????

Thanks,
Jason

 

[Outsider]

Re: New motor sits too high

Do you think a hydrofoil will help so I don't have to rebuild the transom??????

No, not a chance! Your motor is too high, your choices are to either cut the transom or get a long shaft motor. I'm guessing a previous owner had a long shaft (the opposite problem to yours), and chose to raise the transom ...

 

[roscoe]

Re: New motor sits too high

A foil would be a waste of time and money.

You need a longer shaft motor. Or a shorter transom. .

 

[huntin dawg]

Re: New motor sits too high

A foil would be a waste of time and money.

You need a longer shaft motor. Or a shorter transom. .

I figured so. The motor is brand new right out of the box so replacement is not an option. I'm going to take the transom down. It was rebuilt so I think I can undo the build pretty easy and modify it.

Wish me luck!

 

[JimS123]

Re: New motor sits too high

You still need to provide the transom height dimension. Also, how about a wide angle shot of the transom, instead of closeups.

 

[Philster]

Re: New motor sits too high

Jack plate? Not sure if they allow as much movement as you need, they might.

Jackplate allows you to lift an engine. It's lowest point will be the lowest point it's at right now.

 

[Maclin]

Re: New motor sits too high

Thanks Phil, good to know.

 

[Mr. Demeanor]

Re: New motor sits too high

Thanks Phil, good to know.

I would try another propeller before cutting into the boat. Maybe a small Trophy Plus. If you could borrow one or I can recommend a place that has a prop trial program that will ship whatever you want to try.

 

[Philster]

Re: New motor sits too high

Do those props even come that small? I think they are large-pitch props.

 

[huntin dawg]

Re: New motor sits too high

You still need to provide the transom height dimension. Also, how about a wide angle shot of the transom, instead of closeups.

Well the transom was 21 inches. I needed to cut 5 inches off. However, I took the rebuild apart piece by piece and found the original 16 inch transom completely intact. All they had done was build it up, probably for a long shaft motor. They went over the top on the build. It was pretty hard to get apart. The original transom was in perfect shape under there. Some paint touch up is all it needs.

Everything turned out much better than expected.

Thanks for the replies gentlemen.

Happy boating!

 

[Mr. Demeanor]

Re: New motor sits too high

Do those props even come that small? I think they are large-pitch props.

The Trophy Sport series comes in 12 and 15 pitch then the regular trophy's go 17-28 pitch. I dont know what kind of pitch he needs but the little trophys would be a good option if they fit.

 

[roscoe]

Re: New motor sits too high

Well the transom was 21 inches. I needed to cut 5 inches off. However, I took the rebuild apart piece by piece and found the original 16 inch transom completely intact. All they had done was build it up, probably for a long shaft motor. They went over the top on the build. It was pretty hard to get apart. The original transom was in perfect shape under there. Some paint touch up is all it needs.

Everything turned out much better than expected.

Thanks for the replies gentlemen.

Happy boating!

Well thats some wonderful news.

Makes that "I screwed up" feeling go away, and saves you a lot of work and expense. Yeah !!

 

[Philster]

Re: New motor sits too high

The Trophy Sport series comes in 12 and 15 pitch then the regular trophy's go 17-28 pitch. I dont know what kind of pitch he needs but the little trophys would be a good option if they fit.

Never knew about the Trophy Sport. Good to know.

 

[huntin dawg]

Re: New motor sits too high

Well thats some wonderful news.

Makes that "I screwed up" feeling go away, and saves you a lot of work and expense. Yeah !!

Yeah it worked out great.

I took it for a run this weekend. Never went to WOT and got up to 21 MPH. I'm still breaking in the new motor so once complete I'll see what it can do at WOT.