Looking for ideas here. 1986 Sun Runner 31ft cruiser. Weighing approx. 10,000lbs. Two new chevy 350 small blocks from Advanced Marine engine. Two rebuilt AQ290a SP drives in 2015. Props are 15.5 x 17p counter-rotating. Added HEI 65,000 volt Marine distributors, timed at 8 deg BTDC @800rpm., and new Edelbrock 1409 carburetors. New fuel filters and separators. Engines start up and run fine once warmed up and chokes drop off.
With 2 adults aboard, I can accelerate to Wide open throttle with the Bennetts down and the boat will plane out at about 24-26 mph. Tacks are reading 3200 to 3400 and I cannot get anymore rpms out of her. If I raise the bennetts up, she will nose up and drop off plane. If I throttle back, she will drop off plane.
I can plow water at 2200 rpm at about 8-10 mph.
My understanding is this boat should cruise at about 3500 to 3800rpm and WOT to 4500rpm.
I had 19 pitch props on it, but it seemed worse getting up on plane.
I am running Quicksilver Aluminum props. I have also installed the Hardin Marine Edlebrock Throttle cable mounting plates and linkage.
One idea I had was... What if the lower gear sets were not 1.61:1 for V8 engines. What would be the result?
Any ideas?
Thanks,
Kevin
With 2 adults aboard, I can accelerate to Wide open throttle with the Bennetts down and the boat will plane out at about 24-26 mph. Tacks are reading 3200 to 3400 and I cannot get anymore rpms out of her. If I raise the bennetts up, she will nose up and drop off plane. If I throttle back, she will drop off plane.
I can plow water at 2200 rpm at about 8-10 mph.
My understanding is this boat should cruise at about 3500 to 3800rpm and WOT to 4500rpm.
I had 19 pitch props on it, but it seemed worse getting up on plane.
I am running Quicksilver Aluminum props. I have also installed the Hardin Marine Edlebrock Throttle cable mounting plates and linkage.
One idea I had was... What if the lower gear sets were not 1.61:1 for V8 engines. What would be the result?
Any ideas?
Thanks,
Kevin