Formula 242 with high x-Dim.
 

Hey Guys,
Bought this boat and did a complete refit. Boat was without power and now its powered by a 502 MAG MPI with stainless manifolds. X-Dim is about 1.5 inch higher as original. Bravo1 drive, 1.5 Ratio.
This was the first test. I have now a Revoloution 4 23p Prop on it.

Boat accellerates and gets on plane perfectly.

2800rpm - 32 mph
3300rpm - 40 mph
3900rpm - 47mph
4300rpm - 55mph --> this is highest speed

This is trimmed ALL THE WAY DOWN. If i start trim her up, i get a massive rooster tail but the boat slows down. I can trim her up to 4800 rpm and she gets 50mph. Feels like the bow does not lift at trim.
Boat has no tabs, driven on a river in fresh water, no chop.

Any suggestions how to improve?

Thanks!

Disclaimer: ibknow nothing about those boats with a higher x than stock.

That said, round table talking….

That prop has a listed diameter of 14.6” diameter. Pretty small for a 502 equipped boat.

The Bravo 22 and 24 have a listed diameter of 15.3”.

Therefore, i’d try (borrow/rent/etc) a Bravo and go from there if need be.

I'd try a 22 Bravo 1 prop. It will carry the bow more. Also, check the last 4 feet of your hull hook. Hook will act just like dragging trim tabs

She has hull hook. I try a bravo1 prop tomorrow!

If a different prop doesn’t get you where you want I’d try a 1 inch spacer and move that drive height closer to where the manufacturer put it.

1.5" higher doesnt tell us where it actually is. I would assume that 1.5 higher than stock is still 3" below. Does this boat have a notch or full v. 4 blade bravo will be a good idea regardless.

I would have to measure where it actually is. this boat is full V.
I tried 24 pitch bravo1 yesterday, it only went 45 Mph @ 4000rpm.
Then i tried Mirage 23, went 45Mph @ 4100 Rpm

I can trim them up to 4800 Rpm and massive Rooster tail but she never gets faster.
With the 24 Bravo1 i had a feeling the bow was mor up as with revolution and mirage.

Rpms are too low i think. I could try now bravo 22 or mirage 21, but i'm not sure this 502 engine should turn a 23 mirage without problems?
Maybe the motor is low on power?

How much hook?? It sounds like the hook is causing your issue and a prop change won't fix that.

Its the original hook. If i remember right its about the last 2ft of the hull, 1 or 1.5 inch down.

Is the hook the whole width of the transom...or just the outer edges?