150HP on an 18' SS...?

[bunker108]

The 1972 Mercury 1150 on my 18' SS is sucking water from the exhaust plate on two cylinders so I am looking for a replacement. I went to look at another inline 6 today but it had low compression on #3. It was a 1975 1500 so the weight is almost identical to my current motor and I could have reused my controls and the power trim I just added. So the hunt continues...

I am going to look at another mercury on Sunday, but this one is a 1981 V6 150 complete with controls and power T&T. This engine is about 75lbs heavier than my current set up.

This is the gray area. The boat is rated to 140hp. Both of these engines are rated at the power head. So they both are less than 140 at the prop. So the first question is this a legal argument that can be made since the shift to prop rating didn't happen until 82/83...? A more modern engine could still be legal for the boat and make more power at the prop than an old 150.

The second question is anyone running a 150 on an 18' hull?

Thanks!

 

[dozerII]

Re: 150HP on an 18' SS...?

That's real good question B2, it has been debated lots on here. The older 16 SS was rated for 85hp and a mid 80's SS was rated for 90hp
A newer Yamaha 90 weight 60lb less than a v4 Johnson of the early 80"s and puts out considerably more power at the crank. What does a guy do?? If you never had an issue big IF not a problem but if you were in a crash or something the POPO is coming down on you.
just my 2 cents
Glen

 

[bunker108]

Re: 150HP on an 18' SS...?

I am going to look at a 1400 Mercury this morning. The only problem is that it comes with a Glastron! But a 140 would be a perfect match.

 

[bunker108]

Re: 150HP on an 18' SS...?

That was a total bust. The 1400 looked like it was leaking water at the exhaust plate too. And it was stuck in gear so I couldn't even compression test it. And neither the boat or trailer where salvageable....oh well the hunt for a suitable repower continues.

 

[InMotion]

Re: 150HP on an 18' SS...?

That was a total bust. The 1400 looked like it was leaking water at the exhaust plate too. And it was stuck in gear so I couldn't even compression test it. And neither the boat or trailer where salvageable....oh well the hunt for a suitable repower continues.

Bunker --- you are bound to find something! Keep up the searching!

 

[bunker108]

Re: 150HP on an 18' SS...?

Still searching, and in the meantime I have pulled the power head and started to tear the old Merc down. Check out the Merc outboard forum for details.

 

[ezmobee]

Re: 150HP on an 18' SS...?

My SS is rated for 150. Personally I wouldn't seek out a 150 for it though and would stick to a 140 as that's typically the largest 4 cylinder. I'm not interested in the weight or complexity added by a 6 cylinder.