That's where I'd start too. Sometimes they take so much cup out of the prop it loses bite. Maybe even a stock B28.

My best prop for my single Nordic was a stock B26 that was blueprinted/balanced, leading edge sharpened, and the in front of the cup he just etched/blasted that trailing 1" for some more bite.

27 Fountain Fever prop help

Stock prop on 27 Fever

and many more.

that 540 have a ‘731 or similar cam ? 226/234 at .050” hydraulic roller ? How about old motor ?

Thanks for that link I’ll check it out. I searched earlier and found a couple threadsI went through.

cam is 241/253 615/630 not sure what the old cam was though.

I like using this calculatore

if you have 1.65 gears then 26P/5800/72mph would put slip at about 17%

Propeller Calculator / Prop Calculator (rbbi.com)

I have a 1.5 gear so I’m over 20% depending on the calculator.

Interesting. But good ! Or should be anyway. Should have made more steam then your reported #'s. You have the real sheet to post ? Sometimes I can see some things on them. Tune issues / valvespring issues /etc...sometimes not Until we the sheet, I'll say engine should be propped to about 5400rpm. Maybe 5500.

Let's get more info, and have you run that with 34-35 total timing and .035" gapped plugs. Ck fuel psi wide open too. Might as well. We are diagnosing right ?

Let's see if I can get this to work. My picture doesn't have the AR like in the full sheet, but hopefully this is enough. I can get a full view if needed.

A/F was around 11.7 > 12 through the full pull.

by https://www.flickr.com/photos/32474676@N02/, on Flickr

by https://www.flickr.com/photos/32474676@N02/, on Flickr

Great points!
I think I am spoiled by the handling/stability at speed as my Formula 311 SR-1 has a flat (no step) bottom, weighs a ton (4 tons), has the Silent Thunder platform (drilled and hollowed out but still quite heavy) on the back of the boat, and Hardin Marine's Mayfair Full Hydraulic steering for dual Bravos.
Believe me, if it got loose my Wife would tell me immediately!

First things first do a leakdown on the motor to make sure it’s healthy. I only say this because you said it felt bad first run and would not plane, and you had a fuel pressure issue. Make sure she isn’t hurt.

Timing shouldn’t be in question, run the timing where they made the power on the dyno. If you are 4 deg short of where it made best power there is a start

I figured out it was just a bad fuel pressure gauge, but coupled with the engine bog it was a big concern at the time.

when I checked timing at 3200rpm my light was showing 40*. Shop said these DUI distributors aren’t great at maintaining timing at sustained rpm. He mentioned this to me when I picked up the boat and recommended I switch to MSD eventually.

I’m not opposed to that if I can appropriately control the timing. He said it peaked on his light at 38* around 4000 and then went back to 34* above 5000.

anyone had experience with these distributors?

Was looking at an MSD all in one with rev limiter built in. It’s the 86306. https://www.holley.com/products/igni...rs/parts/83606