out of control @ full speed...????

[thehotrodguy]

So I have recently installed a 520" BBF Stroker in a 1979 21' hawaiian v-bottom with an open-bow. Berk JB-12 with an "A", loader grate and a hyd place diverter (no rudder).
Boat runs great, sounds great, and has no problem getting to low 70's with me & my pal Gary. Seems that when I trim it just right, I can get 78 mph @ 5200 rpm. I was aiming for 80 - 85, so I guess the NOS will come out next spring, as the season in Maryland is about over.
Funny though, a few times I lose control - the boat veers left, I turn right, boat still left, I trim down, let off throttle, and I get control back. After the first time, my buddy suggested a wedge, which I added (6 degree) - the problem is still there on rare occasion, seemingly without method or madness - but with the wedge I actually got REALLY nervous - the starboard side started to lift and I felt very helpless. Scared myself silly, actually - although I stayed out "testing" for another hour, running at speed with only one very minor repeat.
So, before I manage to destroy this boat with only 5 hours on the motor.... help?

[suckin&pumpin]

hmmm I am just about to buy the same boat as a project maybe I will re consider.

[thehotrodguy]

hmmm I am just about to buy the same boat as a project maybe I will re consider.
Other than the few times it has violently turned left for no reason, I really like the boat - very stable.
check it out: (cameraman is only 10, video not great)
http://www.youtube.com/v/H_bfLlxBu1g&rel=1

[RIVERTIME247]

Other than the few times it has violently turned left for no reason, I really like the boat - very stable.
check it out: (cameraman is only 10, video not great)
http://www.youtube.com/v/H_bfLlxBu1g&rel=1
SOUNDS LIKE SHE WANTS TO BE A CIRCLE RACER!

[cyclone]

if you are losing control of the boat at wide open throttle when the roost is as high up as it is in the video, then that is the problem.
did you install the wedge so that the nozzle pointed higher up or down? wedging the nozzle up will only make it worse.

[franky]

I think I am going to hurl.

[thehotrodguy]

if you are losing control of the boat at wide open throttle when the roost is as high up as it is in the video, then that is the problem.
did you install the wedge so that the nozzle pointed higher up or down? wedging the nozzle up will only make it worse.
I did it to point the nozzle up. The jerk left happens with tail up, but not necessarily all the way. If it hapens again (and I'm guessing it will) will I regain control if I flick the tail down lower? Obviously the wedge needs to come off (or point down) - but the million dollar question I have is
WHY
does it go to the left, and why so suddenly & violently? I want to understand the problem....:idea:

[396_WAYS_TO_SPIT]

You mave have hook in the hul:idea:

[thehotrodguy]

I did identify some hook in the hull prior to installing the motor - but it is on both sides. I don't understand why that makes it go left - never right, just left.
The other thing (I forgot to mention) is that the intake is slightly dmaged - a small chunk missing on the right side - like an inch long by 1/2 in tall... I have a hard time believing this matters much, but I want all the advise I can get, so I'll share all the info I have

[Ralph Brunt]

lower the diverter to 4 feet off the water and see if it does it, your going slower with that big tail