241 speed

[tomtullyconstruct]

Hello all my new to me offshore 24 was bought with a bad motor a new sei alpha with 1.47 gearing I installed a non vortec rebuilt 5.7 from my local machine shop so hp is unown but estimated at 260 what speeds should I expect so far I’m disappointed with my cruising speed with 15/15” stainless pro tech prop and my 14.8/17 solas prop doesn’t get me into the correct rpm range

 

[Ekea]

what rpm and speed are you seeing at cruise and wot currently?

 

[DennisG01]

A Merc small block typically has an RPM range of 4400-4800. I'm not sure what type of "rebuild" you have. What are you getting with each prop... and are you trimming up as high as you can go (just before ventilation)?

Speed is secondary to RPM. Dial in the RPM and the speed will follow.

That said... there are VERY few sterndrive versions of your boat out there -- see my signature -- but I would expect mid to upper 30's... "maybe" touch 40. This would be assuming you are talking about 260HP AT THE PROP... however rebuilds are often rated at the crank and you will lose 25-ish HP by the time it gets to the prop.

 

[tomtullyconstruct]

Thanks for the reply the rebuild is from a reputable machine shop where I am freinds with the owner he built this for me 8 years ago and it sat luckily it runs well he did a complete build starting with a block he had has all new internals so the hp and specs on cam are a mystery I was still breaking in so was going east but got to 4400 rpm and backed off with the 15/15 protect stainless going to try again with the 14.8/17” solar as but felt it was a struggle to hit 4000 rpm it was a little ruff that day the motor is new and I has a chirp in my belt (was a little nervous to push

 

[tomtullyconstruct]

I was hoping to st least cruise at 25-26 and thought that was reasonable I have cast iron high rise intake and Edelbrock 750 ffm carb