lloyd

I am trying to help my brother with his 22' regal/velocity. I am confused with the way the boat has reacted to the three propellers we have tried so far. First prop is a 26P Bravo 1 4 blade. Strong mid range 4800 rpm max 73.7mph on gps. Easy to get on plane, strong mid range to the maximum observed 4800rpm. Second prop 28P Bravo 1 4 blade. Slower to get on plane (although not a problem),still strong mid range same 4800rpm max 78.0mph. Third prop is a Hydromotive 23P 4 blade (they told me the 26P Bravo 1 actually measures 25P) planes easy seems to slip in mid range 63.5mph at the same 4800rpm. The engine is a warmed over 454 that dyno'd at 545ft/lbs@4400rpm and 461hp@5100rpm. This was with a very lean carb that we later found out was due to a fuel supply problem, but I would think that the power peaks would be very close to the dyno rpm's. The question I would like to ask is why am I not seeing any rpm change with these various propellers. I am going to call Hydromotive tomorrow but would like to hear a few different points of view.

Turbojack

Rev limiter somewhere? Bad Tach, or are you using MSD box. I had problem 2 years ago. Motor would screem to 4800rpm & then fall flat. Talked to everyone & got all kinds of answers. Install friends MSD box & then motor ran to 5700 rpm, Put old box back on & 4800 again.

Griff

Sounds like it running out of of fuel at 4800rpms. Check your fuel pressure, floats and jetting.

lloyd

The ignition is a Crane unit with the rev limiter set at 6000rpm. We used the ignition during dyno testing. The tach is a brand new Autometer and I have hooked up my Mac Tools scan tool to verify the rpm. We have not changed the fuel pressure guage, but that is next. I don't think it is a fuel supply problem because we have warmed it up, installed new plugs and run it hard, shut it off and pulle them. We are rich by probably 2-3 jet sizes. Last night I was thinking some more about this and thought it may be the mufflers. These look like the type that belong on a cabin cruiser.They are 2' long 1' in diameter 4" id and made of fiberglass. I could not even find them on the internet. We are going to remove them and try again.

throttleup

Did you change the Rev Limiter Chip when you "warmed over" the engine?

Julie

merlin540

sounds like rev limiter to me

throttleup

Air flow to engine compartment?

Julie

Turbojack

You did check & make sure the throttle blades open all the way? I would still get someone else ignition box & try it. Wire going to distributer is out by itself & not with other wires?