For the 4 stroke Merc guys that have ran a Pro Max, did you have to run the blow out ring and what was your PVS set up?
Thanks
For the 4 stroke Merc guys that have ran a Pro Max, did you have to run the blow out ring and what was your PVS set up?
Thanks
No ring & all holes plugged solid. 300R 1.60 SM.
‘17 Bullet 21 SDC ‘20 Merc 300R 1.60 SM 1E081012
I bought a new 29P ProMax just before swapping from a 250 ProXS with TM to a new 250R with SM. I have a 20XD with 12" Bobs Hyd plate. It's loaded pretty heavy with 24V Ultrex & 10" graph in the front as well. I could not get on plane with the prop on either motor. Starts off like a freight train then just before laying over the prop will completely blow out. Tried it with and without blow out ring, worked with adding/removing plugs. Sent it to Steve's Custom Props and had cup added to the tips--still no help. Before making comments I run a 29P Bravo (I know the pitch is variable) which is a full 3/4 bigger wheel It will jump up on plane with it. I've also ran a 28P ProMax that had 4 non-PVS holes added in addition to the 4 regular ones. It was a little tough to get on plane but it was doable. Also tried, 27 & 28 Hydros, and a couple over the hubs props with little success. I guess I'll have to come off the wallet for a Max5 next???
I've seen where a few guys can run them but have spoken to others that they can't. My theory is that the ProMax being 14.5 inches does not have enough surface area to hold water as the lower unit angle transitions as your getting on plane so it looses bite and blows out. Been running Bullets for near 30 years now but I'm far from a prop expert. I find one that does what I want and stick with it but never has it been this difficult!!
I ran it this past weekend. No ring and all the holes plugged like JP suggested. Holeshot wasn't bad. It did blowout on breakover but nothing ungodly. I liked how the prop drove and handled. I really didn't get to stretch it out but did run it up to 75. I like the Bravo better for a fishing prop but I expected that.
Promax has been one of the fastest accelerating props on my 300r. It however don't like the engine heights the R is capable of running at. It became a 3.5 blade in a little over 3 hours of break in.
Allison XB21
Mercruy 300r
I have a 20XDC, last year I went to a 250R, and at that time was able to have it flashed. 14" Bobs hydraulic plate. I fought the blow out issue really bad with just about every prop I tried before going to the hydraulic jack plate. The hydraulic jack plate helped but didn't solve all the blow out issue. I finally tried a 32p Max 5 and it was crazy how it worked. I was trying to get the motor to spin up quick thinking thats what it needed, but with the 32p 5 blade it pushes the boat and it lays over real soft like and never blows out. My prop guy claims that the best way to prop the 4 strokes is to run the biggest prop you can find, knowing it will not turn it and work back from there, rather than work up from smaller props. The smaller props seemed to dig a hole with my boat and when it broke over it would blow out hard. The 32 doesnt dig the hole it just pushes and lays the boat out with very minimal bow rise, and thats on a 20'er.
I'm running neg wedges and they made a big difference on my boat. I ran it without, then added and could see a big improvement. I really like the Max 5, so far its been the best prop i had tried for hole shot, mid range and top end, all around good prop. And I'm running a decent load too, I tournament fish so I'm not light by any means.
As much as I hated doing it, I added a foil, and that helped more than anything I have done or tried. I'm not a fan of them at all (as far as looks), but with the results I saw I figured I would live with the ugly thing.
Sowenssw
You need to call me about adding a foil to the sporty lower unit
2020 Allison XB 21
Merc 300R
2018-SST Bullet
Merc 300R
Bullet 20XD
300XS DBR
Bullet 21XRS 250 pro xs serial#2B775575