SPORT 15 Engine Mounting

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alan-bc
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Joined: Tue Jun 29, 2021 7:13 pm

SPORT 15 Engine Mounting

Postby alan-bc » Tue Jun 29, 2021 7:50 pm

I've just purchased a c.1984 SPORT 15—my first powerboat. I've been a sailor for for nearly 50 years.

I am, quite frankly, delighted.

The boat is currently sitting in my driveway. I'm dying to get her in the water but there's a few things I want to take care of first.

As such, I'm sure I'll have many questions of this forum, the first being the location of the outboard.

It's a 50 HP Mercury 4 stroke EFI built in 2010, and obviously it's not the first outboard on this boat.

However, the outboard mount has many holes allowing the motor to be positioned at many heights. This leads to several questions.

What is the correct [engine mounting] height?

Right now, it's using the holes next to the top, so it could be raised by several inches or lowered by an inch or so.

If height is not that critical, why wasn't [the engine mounted] right down on the transom?

As it is, the outboard is held in place entirely by the four bolts. The L-bracket on the front of the mount is sitting in the air.

Thanks for any answers.

Alan

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Phil T
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Location: Was Maine. Temporarily Kentucky

Re: SPORT 15 Engine Mounting

Postby Phil T » Tue Jun 29, 2021 10:08 pm

The engine is at the proper height. One hole up.

You don't want any more of the leg of the engine in the water than necessary.

The engine is attached with the bolts. Having it sit on the transom is not recommended.

What prop is on the engine now? Stainless or Aluminum. Make, model, diameter and pitch? The part # is stamped on the inside of the hub.
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jimh
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Re: SPORT 15 Engine Mounting

Postby jimh » Wed Jun 30, 2021 8:06 am

Please read the FAQ answers at:

https://continuouswave.com/whaler/reference/FAQ/#Q8

https://continuouswave.com/whaler/reference/FAQ/#Q9

Since you are new to Boston Whaler boats and new to power boats, read the entire FAQ:

https://continuouswave.com/whaler/reference/FAQ/

For more about the 15-foot hull read the REFERENCE SECTION article on those models:

https://continuouswave.com/whaler/reference/13/

For more about engine mounting height read:

https://continuouswave.com/forum/viewto ... 4920#p4920

For particular advise regarding engine mounting on boats with shallow engine splash wells (like a c.1984 SPORT 15 boat) read

https://continuouswave.com/forum/viewto ... f=7&t=5808

Engine mounting height is made adjustable because the optimum height depends on several factors, not every transom is identical height, not every engine is identical length, and not every hull has identical shape and form. Tweaking engine mounting height is like proper sail trimming.

jimh
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Re: SPORT 15 Engine Mounting

Postby jimh » Wed Jun 30, 2021 8:27 am

The engine as presently mounted at a one-hole-up elevation is quite likely in an optimum mounting position for general use of the boat. Don’t worry about the mounting other than to check all four mounting bolts are secure and tightly fastened—but not so tight they crush the hull laminate.

alanbc
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Joined: Wed Jun 30, 2021 10:37 pm

Re: SPORT 15 Engine Mounting

Postby alanbc » Wed Jun 30, 2021 10:56 pm

Phil T wrote:What prop is on the engine now? Stainless or Aluminum. Make, model, diameter and pitch? The part # is stamped on the inside of the hub.

The prop is painted black, that's about all I can say. I assume that since it's painted, it's aluminum. There IS a number stamped into the outside of the prop but the paint is so thick that it's really not legible.

Sadly, the boat will likely not be back in the water for a while.

The previous owner sorta kinda warned me that the steering could be "a wee bit stiff" if left unused for too long. I assumed dried grease in the steering cable and so wasn't too worried. But when I took the cable off today, I found the cable is fine, it's the motor pivot stem itself that's stiff—really stiff. It DOES move but takes two hands and a very firm twist.

Looking closer, there is a LOT of grease out the top of the post, so I assume the previous owner tried to fix the problem with a grease gun.

Tomorrow, I'll see what I can do about flushing out the old grease and refilling it with new. If that fails, I'm looking at a very big job.

Thanks for the reply.

jimh
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Re: SPORT 15 Engine Mounting

Postby jimh » Thu Jul 01, 2021 7:01 am

For advice on repair to the engine steering tube, use the REPAIRS and MODIFICATIONS forum.

For advice on propeller selection use the PERFORMANCE forum.

The very stiff steering is like due to rust in the engine mount steering tube, which as you mention, may take some effort to remedy.