That looks like alot of fun. When I drive the Venom I tuck the motor in for takeoff to limit bow rise and then trim to about neutral or slight positive. I have a hydraulic jack plate and keeping the prop shaft even with the bottom of the pad seems to work well. I am sure that I have slack in my steering that needs to be bled out. The Venom never porpises but does want to chine walk at 75 and above.
Chine walk probably means the motor is too low. The boat tries to climb up on the gearcase creating the instability. From what I have read the propshaft centerline needs to be about 1 1/2 inches above the pad on that boat. Just watch the water pressure. I have no idea why I am helping you go faster. jim
That is funny Jim. I dont know either but I may as well pick your brain since it is here. I have run the prop shaft 1 to 1 and one half inches above but it seems to me that even does the best. The hydraulic jack plate allows me to experiment. It sure is fun to play with this stuff and I have also heard that 1" above is the sweet spot. Again I think tuning up the steering will get me thru that sonic 75mph barrier. XXXXXXXXXXXXXXXX What is the max stable safe speed of a Hydrodyne? I am thinking about 60 and if I prop mine for that I may consider letting the Venom go.
I have never heard of one acting up at speed. The max I have seen with mine is 55 with a torque shift prop which will increase the pitch to maintain the rpm it is set for. It works like a constant speed aircraft prop. It starts at 13 and can go to 26. I doubt that raising the engines will work on the Dyne. jim
Here are a couple of pictures of my 21 foot Trick Cat powered by a 300XS Mercury with a stage 1 DBR kit on it. Boat will run a tick over 110 mph and is hard to steer but stable at that speed. It likes a light chop to air it out, and has taken alot of seat time to get to know what it takes with the trim and engine jack plate to get the best out of it. Too much jack plate and it will run out of water pressure, even with a thru-hull water pick up.
Bob, I wonder if jacking the motor even higher would let the hull settle lower and get the water pressure back. It might be trying to ride on the gear case. jim
Jim, I've tried running it higher on several ocasions but always the same thing. It will lower the water pressure, and it doesn't take long before the alarm goes off and if you run it any longer it will go into guardian mode. Granted finding the right kind of water to run these speeds on the river isn't real easy to do. You've got to be real carefull. The good thing about running a stock 300XS is we use this boat as a pleasure boat alot of the time. It's got a comfortable large interior, and with the tunnel design it takes the large cruiser wakes nicely. I run a 19 pitch High 5 prop on my 18 footer with the 250XS Merc. It pins the 50 M.P.H. airguides at about 3/4 throtle and will ring the over rev chimes before I can really run it out. The prop is Ideal for the skiing but not enough pitch for any top speed running, which I don't do in that boat.
I like the side mounted steering cylinder. I don't make speed runs in the Dyne either unless I de-activate the airguides. jim
