I recently purchased a sportv 4400 black death on a 17x51 excel f86. Everything is used and 2016 model. Motor is all stock except for voodoo exhaust. Just recently put a raptor 3 blade on it hoping to get a little more top end and I'm still only hitting 19 to 20 tops. Any suggestions???

You can just see the top of the prop running about 3600 rpm, if I trim it up or down I lose speed. That is with myself and one other guy otherwise an empty boat. Motor has 104 hours on it. As far as transom/ motor height I have no clue if it is correct or not, the shaft of the motor sits just above flush with the bottom of the boat. This is my first mud boat so I'm a cherry to all of this.

I'll check all that. I appreciate it

I think the raptor you bought may be 12x11 ( 12 inch diameter and 11 pitch )

The original MB Big Blade was a 12x10 and they may also have had a 10x10 at one time....

Your MB 4400 was likely offered with several top and bottom gear options and may
have "tall gearing" which would respond well to less pitch on a heavy hull like yours....

Your motor needs to wind up to 3900 to run best and also the healthiest....

These motors don't like being lugged down where 3500 is all they can turn they
will overheat and experience more wear and tear than they should....

You should also verify visually with motor OFF that you can fully open the carb butterfly
and then run prop out of water to verify your rev limiter will allow you to gradually spin up
to 4200 rpm - which is about as many rpms as is safe to run long term....

After that consider a pitch change or that valve leak test....

Lastly buy good 93 octane fuel - toss any old fuel and clean or replace filters....


Good Luck !