502formula

Hi, I have a 88 formula 242ls. It has a fresh built 509 mag mpi. Couple little goodies (cam roller valve train etc) I'm having problems with finding a prop. I see these other guys with this boat and motor combo running in the mid 60s.

First prop I tried

23p mirage plus. Could over spin and blow it off

23p 4 blade Merc evolution, could spin to 5100rpm and see about 58mph

25p Mercruiser stainless 3 blade. Could only spin to 4800rpm, forgot to check speed

Now I have a 23 mirage on there (which is what everybody recommends for that boat) and it runs good with it but I can get on plane and do the initial trim up up and put it to 5100rpm seeing about 56mph.. The stock formula 242 with 454 runs that speed..

If I put all those numbers in for the 23 mirage on the slip calculator, it says I'm getting 23% slip..

Any help would be awesome, thanks

chewymalone

I had a 1990 242LS a while back. With the stock 454 (365HP) I ran 58 with a Mirage (non plus) 23P. I built a 620HP 496 and went to a 27P Mirage Plus and ran 71 at 5100 RPM.

502formula

That's what I'm saying. I'm not getting it

502formula

And that's what I have on there is a 23 non plus. Think the prop could be worn out? It run smooths and no dings, clean looking prop

502formula

Anybody?

502formula

bump

PARASAIL941

Make sure you have enough timing in it . Sounds like a power problem, Good luck!!!

502formula

But would it be a power problem if I can spin it all the way up to 5200rpm?

PARASAIL941

Yes , a motor can still turn up full rpm without making power. If your motor made 250 hp on the dyno , you could get it to spin 6000 rpm if you keep backing down on pitch . Check timing , throttle opening , ect.

502formula

bump