Pro Max maximum RPM

[allimax]

What type of RPM's are you guys obtaining (or should I be obtaining) with a stock 2000, 225 PM? Motor is fresh, 1/8" below pad, Hydromotive OT 27P, .090" stock lip on a '03, R32 ECU. Seems to run out a 6200.

 

[flying07]

I run a Brucato box with standard curve, spin my Promax to 7400 with a 26 chopper 1/8 below the pad. Hope that helps! Oh, also has shaven heads and my sporty was worked by Todd at Hydromotive, that helped HUGE!!

 

[allisonjr]

I'm having a similar problem with mine. I also have a 2000 225 promax. I have been running a 30p lightning et and I broke an ear off of that last Saturday. I am using a spare hoss cut chopper prop 26p. My engine is only turning around 6100 rpm.

 

[GotMyAlly]

Put a smaller prop on and it should turn to the limiter or a little past if it's healthy. I'd want to prop it to run right at 6750 or thereabouts if it's stock.

 

[jcoats3]

Mine will turn right at 6275 to 6300 loaded to fish with my 27 pitch hydro OT. It will turn my 24 pitch XOT to the limit at 6850. Pretty much stock 225 pm .15 over from rebuild. Now that is in 90 degrees heat with high humidity so nice wether might do more.

 

[90 5.0]

With a factory ecu and a short wheel I've had them flash to 74-7500 before and hang there

With a big wheel and factory ecu I have had them push 7.

Limiter removed and short wheel mine turns 8400 in the 1/8th. Bone stock with cut heads and recurved ecu.

With my 26 hydro I can turn 7600 and a 28 chopper 7400 with the good ecu

 

[Lakeman (Allison)]

What type of RPM's are you guys obtaining (or should I be obtaining) with a stock 2000, 225 PM? Motor is fresh, 1/8" below pad, Hydromotive OT 27P, .090" stock lip on a '03, R32 ECU. Seems to run out a 6200.

I have a 1997 XB 2003 with a stock 225 Promax with a sm lower unit with a allison cut. Running a worked 30 et lighting. And running 6800 - 7000 rpm. 9/16 above pad.

 

[FlatOutAlly]

When fairly new, mine ran 94-95 at 7ooo with a 30. Fairly repeatedly. Not very useful though. Then I figured out a 26 and the ride to 90-ish was a lot more fun. Shortly thereafter, Merc told me to 'fix' their motor with a firmware upgrade and backing off the timing 2. Rig lost 5 mph and a LOT of snort. Tossed a ring pin 10 hours later. It was gonna happen anyhow, I guess. Still think Promax's are the best value/performance choice for the non-Hanle crowd. Run good. Last. 'Cheap' to fix.

 

[allimax]

You're hitting 7K? Is that with a stock ECU? I ran her with a 26P OT and new plugs this weekend just to see. Maybe I just need a bigger lake like TN to have room to stretch her out more but crap, I struggle to get over 6K. It was feeling today like it needed more timing, ran OK just missing that punch. Engine was set at 23* but I haven't verified that. My other thought is having moved all my tackle up under the front deck could be an issue. I was going to pull it all out this morning early and run her to see but that mountain air makes it soooo hard to get up. I noticed several guys at the Ralley with a quick release and no trolling motor, can that weight make that big a difference or is it more air flow?

 

[GotMyAlly]

Trolling motor is about 1 mph in my experience. That was the difference I saw with a 24V motorguide on an XB03.

 

[catfish123]

I agree with Neal. I never saw more that .5 to 1 mph maximum difference when removing the trolling motor. If you are struggling to get a 26 to 6000, something is definitely wrong. It should hit that in a rather short distance.

 

[90 5.0]

What's your elevation? That plays a huge part in it too

 

[Mick]

I ran mine today bob. There is an issue there somewhere. Turning a 26 trophy, 6k on the tack is easily obtainable, with no problem hitting 7. Did you do a compression check? I'm not a mechanical guru but I'd start with that. Something is definatly wrong if you are hitting a wall @ 6k.. My lake is very similar to how you described yours to me, you should have no problem stretching her out within a couple miles..

 

[Mick]

Also have you pulled your plugs to check how there burning? Could be a simple electrical problem where your not firing correctly on all cylinders. When
Roy had mine he found my trigger, and stator were bad. Seems odd that otherwise it's running fine though. Amy problem coming out of the hole??

 

[FlatOutAlly]

You're hitting 7K? Is that with a stock ECU?

Yes. With an A17 box (the one before the infamous update). With the newer curve (A32, maybe?) you'll be lucky to hit bust 6700. I agree with the others, if you're stuck at 6000, something's wrong and it's time for some debug. Compression, leakdown, electrical check, fuel system, etc.

 

[allimax]

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?

 

[allimax]

No, jumps out of the hole as good as ever. Put new plugs in this weekend, made no difference and they all looked fine. It shouldn't really take two miles to stretch things out, I know I'm impatient but, really?

 

[allimax]

struggling to get a 26 to 6000.

I shouldn't say it struggles to get there, it's getting past there that's the problem. Really she pulls pretty good to that point, then it just kinda hangs there and bumping her up on the trim makes no difference. With a car when you hit the limiter you can feel it, what's a 2 stroke do? I wouldn't think they would start cutting fuel because you need the lube so maybe it's time to send the ECU out.

 

[allisonjr]

My engine is having the exact issue. I haven't figured out what it is yet. It's almost like if you didn't know better you'd swear 6k is all it will turn

 

[allisonjr]

I have changed my tach and it didn't change anything. I'm missing several mph. What's weird it will hold 6k and not miss or anything. Like allimax says its like it hits a wall. I think if I put a 23 on mine it would still stop there