Quent

I just got my new BBblades Maximus 5 Blade. I installed it, ran it, came in and put the boat on the lift to find 4 of the 5 blades bent at the tips. I am running a shortie and it is not as long as the upper at the trailing end of the upper. There is a trapizoidal shaped smooth, no fin, aluminum plate with a countersunk allen head bolt. That bolt holds the cover plate on to the upper. This bolt and plate reside just above the prop tips as they rotate. Even though the bolt that holds the plate in position was coated with red Locktite and tightened securely, it backed out enough to let the plate come loose and you can figure the rest out for your self. I now know of others who have suffered this problem.

I am going to leave this #%&*@ plate off in the future. I can't think of a 4 letter word bad enough to call it. Its a prop eater. Quent

shawn

I remember reading it was almost impossible to get on plane without that plate. Don't get far from the lift before you test.

Wobble

They sell a flat plate to replace the one you have, or you can just cut off and grind smooth the one you have. As you have found out, it is not compatible with larger props and most performance applications do not have them, just the flat block off plate.

They can be adjusted to counteract torque steer on single applications by rotating them one way or another.

rws

Since I am waiting to get my new -2 lower housing back from my drive guy and will be bolting it on tomorrow night I have an interest in this thread .What force caused this plate to come loose?Do you think that the water pressure at the tip of the prop bent the plate allowing the 7/16-14 flat head to come loose?

zt260

Generally speaking you want ¼” minimum clearance to be sure you will not hit anything. If you have the clearance and the bolt is properly loctited you should be fine. I’ve ran a maximus with a shorty for the past year with no issues.

Quent

Guys, the plate I am talking about is flat, about 4" long and 2" wide. It has no torque fin on it. You have to use it when you have an IMCO shortie lower and Max Machine upper combination at the tail end of the upper. My regular length IMCO bolts up and covers the section of the upper that requires the plate when a shortie is used.I assume you have to use it with an IMCO upper as well. I believe the water off the prop beats the crap out of this thing and loosens it. The absence of the plate did nothing negative to planeing when I put my B1 32 on the lower.

zt260

Did you ask Brett about this?

Quent

Yes. I ask both Brett and Aaron at Max Machine. Both said to try it without the plate. When I get my repaired Maximus back I'll have an idea after I run it. Its almost not worth even putting the plate back on for a test. I don't want to put my $1600 prop at risk again.
Green Locktite might work but if the prop seems to work well, I'm finished with the plate.

Indy

JROMY had the same thing happen, Merc calls it a splash plate and it's near impossible to get on plane without it if you have a high x. I think the new one has a few more bolts than the original and won't come off now. Seems that Merc is aware of the situation and has modified the plate. PM JROMY for specifics on what happened to him.

kjm5125

Had the exact same thing happen on my 382 Fastech! The old splash plates were made out of pot metal and they cracked and broke off! Merc sent me two new stainless plates that were slightly thicker. To install the new plates on each drive, I had to drill two 3/8" holes through the flat portion of the drive and insert two bolts with lock nuts. I also installed the short head hex flat screw, with Locktite, and one long head hex flat screw with a lock nut. Went for a ride, pulled the boat out of the water and on the props the leading edge of the props the blades were flattened! Called Merc and they told me you need 3/8" clearance from the blade to the bottom of the splash plate. I had the clearance, the problem was the short head screw loosened slightly and the blades hit it. Once Merc found out I was spinning Hydromotives they quit helping me. My solution was to remove the short hex screw and I have not had a problem.