Pat McPherson

320HP/350 small block on an alpha is fine if the drive is in good shape...
Merc still sells the 300HP/350 hooked to an alpha today...

Sonic30ss

Thats a tough call as far as doing something differnt, I don't know. On one hand they are very unique (read cool), most people have not seen them before, and when they run they run well. However the lame ass stock engines I put in are so reliable that I have had the best season of boating since I've owned the boat. All in all I'm a gearhead (glutton for punishment) so most likely I'll rebuild and DYNO them before they go back in this time so I can be SURE they will run correctly and not have to spend any precious boating time tinkering (at least on the motors).

First thing I would do on yours is to go back to basics, change cap,rotor,plugs,wires, fuel filter...just a good tune up.
Make sure your tach is accurate the built in rev limit is 5600 rpm. BE SURE to check fuel pressure @ WOT (lost one to this). You can get a good EFI fuel pressure tester at NAPA, it will screw onto the schrader valve on the fuel rail/bypass block and it has a rubber hose so it will quell the pressure pulses from the fuel rails. You need two people to do this while running, one to sit and watch the guage and one to drive. Do not leave guage on all the time just run your tests and remove it.
Good luck

andrus.home

I have read much about the rev limiter...since Griffs suggestion ( thanks ), it really sounds like this might be what I'm experiencing. Is it the Mirage prop that is causing the boat to hit the red line at WOT? I cant believe it would be set up so I cant put the throttle all the way without it hitting the rev limiter. I am putting all new gauges into the boat and hope this will give me an accurate RPM reading after which point I will know exactly what RPM it is kicking off at.

Any suggestion on what I should be doing to correct this REV Limiter problem?

BTW I love this boat and I dont even have it in the water yet..lol

Iggy

If it is the prop, ask the owner if it was changed to a lower pitch. If the they used the boat for skiing, tubing, etc they may have changed props so it pulls better.
Either way we still need to know at what RPM this is happening.

Sonic30ss

Check the props for some numbers, I could pull 5500 with 14 3/4 X 21 pitch Mirages.

obnoxus

My first thought is rev limiter as well,,,, dont trust the tach to be acurate.

if its consistant ,,, thats probably what it is.

See if you can get your hands on a larger prop just to check.

davids94

When I first bought my boat I had this happen - I never got a chance to figure out what it was because the motor (302 EFI) blew on me. My orignal engine LOOKED clean but once i took it apart it was in horrible condition. My problem was not a limiter issue, I was only hitting 4200 RPM at WOT.

I would have someone else look over the boat (besides the guy you bought it from) to let you know what kind of condition it's really in. If you have to spend a couple hundred to have it done its worth it in the long run.

andrus.home

OK the boat was finally put on the Dyno last night and it is the REV limiter thats engaging to early...So now I need to get my hands on a new ECU for this boat??

any body have one available anywhere?

thanks

Jeff