Posts: 3514
Location: Elk River, Minnesota | Hi Reef Hawg,
First of all, I would agree that I think the pitch of the prop is probably too high, which, when you try to trim and you are not at the high end of your RPM range the boat will tend to porpoise...the motor is not generating enough power to keep the bow up, or it is not keeping it's bite on the water.
I would suggest trying a lower pitch prop first before lowering the engine height. Most V-hull boats run better when the anti-ventilation plate is roughly 2 inches ABOVE the lowest part of the transom. Most boats are set up so the plate is even with the bottom of the keel due to people just wanting a boat that gets them from point A to point B and nothing more. Problem is, with the lower unit THAT low, the boat will NEVER reach it's full potential for efficiency.
Going to a lower pitch prop on that rig will definitely help hole shot, and it will probably also take care of the porpoising as well. I would suggest trying an aggressive steel prop like a ballistic which allows you to run high motor settings yet grab well. It will also keep your RPM's up more than other steel props because the blades are thinner. They are still tough, but with any prop strike at speed, you will see damage (aluminum or not) with that motor in particular, getting your motor to 6000 RPM when the boat is lightly loaded is going to give you the best overall performance in all situations.
I have a 90 2 stroke on a 1000 pound boat, and granted it is 2 stroke, a 17 pitch does really well for me.
On a side note, if you end up moving your motor down, please DO NOT remove the lower bolts to make the height adjustment. You can use the method mentioned, but if you remove the lower bolts, there is a higher probability of the motor falling. We're talking 370 pounds balancing on a small block of wood and ALL of that weight on your skeg.
Block the motor as stated, then remove the top bolts. Loosen the lower bolts enough to allow the motor to move. Then, crank the trailer jack down to raise the rear of the boat to the point where you can re-insert the upper bolts. silicone and tighten. You're all set. It is not as hard as it sounds at all.
Keep us posted...
Steve |
