Will a 50 horse engine be enough?

[starcraftlegasea]

Hello all,
I have been searching around for an engine for my father's 1978 21 foot starcraft aluminum CC and I found one that I like. The problem is is that it is a 1995 two cylinder 50hp evinrude. I know that this is on the weak side of the scale but I really only want the boat to be able to push me around a bay to do fishing with maybe the occasional tuber out the back. The boat originally had a 1978 70hp mercury that was able to push it just fine, and I know with the change in power ratings in the 80's that this modern 50 will be closer to that old 70 then it seems. So, should I go for it or wait to find a bigger engine? Any suggestions will be greatly appreciated. Thanks

 

[DRIFTER_016]

Re: Will a 50 horse engine be enough?

If it were me, I would wait to find a bigger motor.
I like to have reserve power to get out of trouble should it arise.
I can't see your boat doing any more than 20 mpn or so with that 50 on it.
What kind of speed did you get with the old 70? 30 mph?
How much HP is the boat rated for MAX?
I would go within 25 HP of the max for best performance.
Also an under powered boat will be hard on the engine and get worse gas mileage, something to think about with todays price of gas.

 

[starcraftlegasea]

Re: Will a 50 horse engine be enough?

Hey drifter thanks for the reply. Yea with the old 70 the boat would do somewhere near 30, although I couldn't be sure because I was only about 8 the last time I was on it. If I would be able to do 25 I think I would be happy. Perhaps this 50 isnt enough.

Thats interesting about the worse gas mileage because I thought I would get better with a smaller engine.

The boat is rated up to a 150 but I think that that would be way way too much power for my liking. Also, I replaced the transom myself (amatuer at best) so I dont think I trust having that kind of power/weight back there.

 

[tashasdaddy]

Re: Will a 50 horse engine be enough?

we if it were rated for a 150 it was way underpowered originally. thru the older 70's produced more power per pound, than other motors. a 50 is not going to tube or ski with that boat. true it is aluminum, but i would look for a good 70 as that is still less than 50 % of rated HP.

 

[DRIFTER_016]

Re: Will a 50 horse engine be enough?

Yeah, I would wait for a bigger motor. Even with that 70 it was under powered. With a smaller motor you have to run the throtle wide open to get decent speed, with a larger motor you can back off into the engines sweet zone (the throtle setting that gives the best fuel economy) usually under 4000 RPM. I know it seems counter productive that a bigger motor will get better gas mileage, some kind of physics thing going on!! You know neutrons and positrons, alignment of the planets and such.