1984 19ft starcraft islander repower

[fishbait2]

I have a 1984 150hp evinrude that I was told had only compression of 80 ,80 and 70,50 and would need rebuilt. The motor seemed to be a monster on the back of the boat. The boat is maxed out at 150hp. I wanted to repower the boat with a smaller Horse Power.
I need help with all the knowledge out there, how small can I drop down?
90hp ? I was told by the dealer that looked at my motor that I shouldn't go under 115hp. I have looked at a number of 19ft older starcraft islanders that had 90hp on them this spring.
My question is how low should I go ,or can I go and still get close to around 32 to 35 mph? And what year motors should I stay away from of evinrude,Johnson,Merc,force? And does Evinrude controlls fit Johnson?
thanks for any Info

 

[Tacklewasher]

Re: 1984 19ft starcraft islander repower

I have an 18' Supersport with a 115 on the back of it. My motor is an 1981.

If it were me, I'd stick the biggest V4 on the back I could. A same era 140 would do me nicely. I would not put a V6 on mine even if I thought it could handle the hp. I like the look of the V4 on the back of my boat.

Is your 150 a V6 or V4? I thought the 150 was a 6 cylinder but you only listed 4 compression numbers.

Back to my 115hp. I am working to break 40 mph, but seem maxed out at 38. It really is fast enough for me as I normally go between 1.5 and 2.5 mph anyway.

To get the same hp in the same era Merc takes a "tower of power" and I just don't think it would look right back there. I would stick to the same era Johnson/Evinrude (they are the same including the controls). 115hp minimum and it would really be nice with a 140. Remember, these motors are over-rated compared to modern motors and the 140 is really closer to 120, with the 115 really closer to 90.

 

[fishbait2]

Re: 1984 19ft starcraft islander repower

Thanks for the reply, The evinrude is a 6, one bank is in the 80's the other 70's with one at 50. My buddie has a 67 Grady white,fiberglass with an 82 115 evinrude and his boat flies. I can't find a good 115hp at this point but their is a number of 150's and 90's . The 115 hp I have found in the Merc .
Does anyone know how I can find out what my boat came with from the factory?

 

[Tacklewasher]

Re: 1984 19ft starcraft islander repower

Thanks for the reply, The evinrude is a 6, one bank is in the 80's the other 70's with one at 50. My buddie has a 67 Grady white,fiberglass with an 82 115 evinrude and his boat flies. I can't find a good 115hp at this point but their is a number of 150's and 90's . The 115 hp I have found in the Merc .

I'd post in the Johnson/Evinrude forum to see what motors will use the same controls. I'd still look for a Johns/Evin 140, assuming the controls all match. Be much more fun than a 115. But a 115 would do the trick as well.

Does anyone know how I can find out what my boat came with from the factory?

Nothing. Would have been powered by the original purchaser with whatever he, or the dealer, chose to put on it. Unless you have that sales slip, no way to know what it came with.

 

[fishbait2]

Re: 1984 19ft starcraft islander repower

thanks for the reply, what do you think a 90hp or 100hp would do on my boat? I'm not looking for a fast boat but I don't want to under power it.
If I can run 32 to 35 Great! thanks

 

[Tacklewasher]

Re: 1984 19ft starcraft islander repower

I had a 70 on and got 28mph. Someone here is getting 30 with a 60. But these are lighter engines. And I think your Islander is a bit heavier than the Supersport (you have a small cuddy, correct?).

But 100 should get you low 30's. But it may take more fuel to run at 32 with a 100 than with a 140.

I guess I would see what you can find in 100 plus but I'd lean to 115 to 140.

 

[Joe_the_boatman]

Re: 1984 19ft starcraft islander repower

I got 33mph (GPS) w/ my Merc 60 on my best run. Average around 32mph.

 

[fishbait2]

Re: 1984 19ft starcraft islander repower

I picked my boat up today. Now starts the search for a good motor. The Tech
at the Starcraft dealer I had the boat at told me I should not go any lower then a 115hp. I have seen 85 and 90 hp on my size boat but have not met anyone to talk about the MPH issue. I would say my boat's weight is 1200lb
loaded. Is there a way of telling the shaft length by the serial number?

 

[fishbait2]

Re: 1984 19ft starcraft islander repower

Boat is repowered, 1995 150 xp Evinrude with VRO . My boat needed a 20 inch shaft ,as I was told to messure from the top of the area the motor rested on
to the bottom of the transom. Motor is the same size as the old one and in great shape inside and out. After rebuild of the floor, Transom ,and new interior
the boat is complete with a great motor. Bad part is that I have a bit more money invested than I wanted too. Just got that Starcraft bug I guess!
Thanks for everyones help ( buy the way I stopped at 45mph as it still had more
throttle to go and the boat was flying TOO FAST! )

 

[Joe_the_boatman]

Re: 1984 19ft starcraft islander repower

.....buy the way I stopped at 45mph as it still had more
throttle to go and the boat was flying TOO FAST! )

Awww c'mon! When you do give it the gas, I'd like to know what your top speed was. Been wondering what a 150 would do on the back of mine.

 

[Tacklewasher]

Re: 1984 19ft starcraft islander repower

Remember, that 150 is 150 hp at the prop. My 115 is flywheel rated at 115hp. Prop is probably in the 90 hp range (and joey's 60 is probably 50hp equivalent) so you have a lot more hp that I do. I could see it doing 50 if you have the setup right, but yeah 45 is way fast enough. Still trying to break 40 myself (hit 38.5 yesterday).

Sounds like you've got a sweet setup.

 

[christianmoche]

Re: 1984 19ft starcraft islander repower

nice boat you got there man.

 

[snowman48047]

Re: 1984 19ft starcraft islander repower

I have a 20' Lund with a 50hp that tops out at 25mph. My 82 Islander has a 150hp that I had up to 35 and thought I was flying...I just bought it this summer and have had some issues and I've only had it out twice.

I seriously underpowered my Lund when I bought it. I am selling the Merc 50 Bigfoot and repowering with a Merc 115hp. I won't ever have an underpowered boat again. Now I have to figure out how to afford a 225 for the Islander...

I think you did the right thing keeping the 150hp. Better to have the power and speed when you need it than not have it when you need it!