Pro Max maximum RPM

[allisonjr]

What is several? Comp, fuel, spark.

With the same setup I was running 85 fairly easy. Holding it wide open with the trim in the same place I do good to get 78 with my 30p Lightning et. I've rebuilt my pulse pump. Took apart the high pressure fuel pump screen and cleaned it out. Replaced fuel line from tank and fuel filter, new ngk plugs, I did have one burnt voltage regulator so I did replace that. Compression was consistent across the board, I don't remember the exact numbers though.

 

[Mick]

I agree with starting with the basics, took these numbers a few weeks ago after we got back from Tennessee.
Compression test showed 140-145, leak down showed 4-6%, 15 hours on engine since rebuild at that time. Elevation where I use her is 2,500'. Not sure what the elevation is at Watt's Bar but 6200 was the number down there. Engine was set up with a DDT and the fuel pump is now fed direct through a relay to bypass the ECU. That was what toasted the motor in the first place.
Hey Mick, what's going on? You ready to try them Susquehanna Flats in the fall?

Yep, I'll be down for a flats trip! Roy's got a guy that does the Ecu's.. I would say with all the info your motor seems fine. Raise it a 1/4 on the plate and c what happens. You did say your below pad? When mine was 1/2 below I couldn't get high rpms either. Even to 1/4 above, she runs GREAT!! I need more prop. My 26 trophy will be all over my 7400 limiter. So far ran it up to 7k mid 80's. That was a very short stint today. Still being somewhat easy til I get a full 10-20 hours on my rebuild.

 

[90 5.0]

I had same issue once would only turn 6, still came out of the hole good and pulled good to 6.

Throttle cable had stretched or something. Re-adjusted and it was fine after.

 

[allimax]

I had same issue once would only turn 6, still came out of the hole good and pulled good to 6.

Throttle cable had stretched or something. Re-adjusted and it was fine after.

Good thought, I checked that before I bothered to break out the gauges.

 

[tony Atwell]

Just curious. You say you adjusted the throttle cable and all works fine now. What's your definition of fine. It tirns up beyond 6000??? Just asking cause I'm in the same boat as the others. Can only get 62 6300 out of my promax. I thaught some one told me that's pretty much what they turn with the stock ecu.

 

[Jr in Jax]

Tony,
My Pmax would always turn to the limiter at 6800 and now turns to the ACU's limiter at 7K [which Jake says I should not do, due to the oil drive gear bushing].

 

[tony Atwell]

I'm happy with the performance Jim. It runs a solid 90 mph with a 28 or 30 mazco 3 blade. I picked up a nice 26 mazco last week. I'm gonna through it on there and see how it does. Figure if any thing it will get me to 90 quicker lololol

 

[tony Atwell]

MY buddy in ga says that it Will last a lot longer at that rpm.

 

[yellowjacket]

Tony , it might last a little longer but not near the fun of turning 7000 !

how are promaxes turning 6850, when the sticker says 6500

 

[GotMyAlly]

Most will turn that or near it with the stock ECU.

 

[JCSmile]

how are promaxes turning 6850, when the sticker says 6500

The mercury "WOT throttle" is 6500 supposedly, but the rev limiter does not kick in until 6850. The rev limiter limits rpm by adding extra fuel, so sometimes you can even go above 6850 if you can burn the fuel.