Repowering a 1976 Starcraft Holiday 18'

[Penage2012]

I would like to repower my 1976 Starcraft Holiday 18' and am looking for some advice from the community.

I'm currently running a 1993 Evinrude V4 90HP, but would like to upgrade to something newer and more fuel efficient, possibly a Yamaha 115 HP 4-stroke. The boat's capacity plate says it's rated for a 150 HP.

Has anyone else repowered a Holiday or Super Sport 18' to a new 4-stroke? Any issues?

Should I have any concerns about the 115 being too much motor for this boat given the increased weight of a 4-stroke?

 

[barato2]

Re: Repowering a 1976 Starcraft Holiday 18'

if your transom is good, i don't see a problem with a 115 even if it's the kind with all them heavy bits up top. what you might do is look at weights of circa-1976 150hp motors and use that as your upper weight limit......this will be your issue more than power if you're thinking in the 115 range. altho remember that 150 1976 horsepower is less than 150 2013 hp because they used to rate motors at the crankshaft and now they rate them at the prop (probably a 10-15% difference de to the loss through the gearbox). due to this rating issue, you'll find that a modern 115 puts out a LOT more than your old V4. if you find your 4 stroke of choice is over your weight figure, you could always go with an ETEC or other DI 2 stroke.

 

[Snox49x]

Re: Repowering a 1976 Starcraft Holiday 18'

I just installed a new Yamaha 90 four stroke on the back of my 77 18' Holiday. I was nervous about the additional weight so I moved the fuel tank to the bow. With the tank up front and 2 batteries in the back it sits very level in the water. The additional weight from the fuel tank in the bow also helps the boat cut the waves better. Very pleased with how it all worked out after a lot of concerns about the additional 4-stroke weight on the back. Think the F115 is a bit heavier than the 90 but I would think it would be fine.....with a little weight redistribution. FYI the F90 pushes it about 37-38mph with 2 people, full fuel and fishing gear. It would pull a steeper prop and probably get close to 40.

 

[Krichbourg]

Re: Repowering a 1976 Starcraft Holiday 18'

I put a 2001 Suzuki 115 4 stroke on my 1977 18' SS. I couldn't be more pleased with the performance. She jumps out of the hole and top speed is 40+. I average about 5 mpg which I am pleased with. I had the same concerns as you regarding additional weight. My research indicated that I'm about 100 lbs over what a 1977 150 hp motor would be. This has not caused any problems or concerns although my plan is to eventually put in a belly tank for fuel. Good luck.

 

[Penage2012]

Re: Repowering a 1976 Starcraft Holiday 18'

Thanks alot for the input guys, it's reassuring to see that you've gone with the heavier 4-strokes without any problem. It sounds like either a 90 or a 115 would push it at a decent speed, and I'm sure the fuel economy on a new 90 or 115 would easily be better than my old (but reliable) 90 2-stroke. I think I'll aim for a 90 HP 4-stroke...and now the challenge of finding one for a reasonable price.

I think you're right about the weight Krichbourg. From what I gather the old 1970s 150s weighed about 300 lbs. A 2013 Yamaha 90 4-stroke weighs 369 lbs and the 115 comes in at 400 lbs.

 

[Krichbourg]

Re: Repowering a 1976 Starcraft Holiday 18'

I searched for a while to get mine. You need to be ready to jump when it comes along because it won't be there for long.

 

[jrs151]

Re: Repowering a 1976 Starcraft Holiday 18'

Good thread.
I'm in the midst of a 18' Holiday complete rebuild. My plate says 140 HP max, so I was first thinking a 90, but now leaning towards a 115hp. What will be unique about my situation is that my Holiday is an O/B model for which I will be replacing the transom for a full-transom (aka getting rid of the splash-well completely & going for a full height stern - like the I/O ) thus mounting the OB motor via an offshore added ballast bracket. I think both the transom modification and the added buoyancy from the bracket is going to complicate my perceived HP limits. That said, I'm still leaning toward a 115hp re-power.