Swamplizard
Senior Member
- Joined
- Jan 20, 2004
- Messages
- 273
- Reaction score
- 12
- Location
- Florida
Martin,
Steve in WA is the only other Harley owner I have ever spoken with and he has been very helpful with ideas.
The boat originally had 500 hp farera (NJ) 454s and the props were 20x23 pitch (3 blade nibral round eared low rake and no cup). When I purchased it it had been on a lift in Florida for 10 years as a project boat with blown motors that could not be repaired - the thread below shows what we went through:
http://pg.photos.yahoo.com/ph/orena...=&.done=http://photos.yahoo.com/ph//my_photos
I made one major mistake in the entire process, I decided that I needed 425 HP and since one motor was counter-rotating that I would go with 502's with carbs to keep things simple. I chose a guy in Ft Lauderdale to build the motors (instead of finding new ones) and though his references checked out he has a crack problem, flaked out and built two POS motors. I can't sue since there is a line in front of me and he has nothing to make good. So, after three rebuilds and many component changes she now runs okay but is under powered. How Steve can run his with 415hp stock motors is a mystery...mine is a dog.
Transmissions are 1.5:1 Borg Warners and I have Arneson ASD8s. She will cruise at 25 mph at 3600 rpm but doesnt sound good - working too hard and guzzling gas. At 3800 it sounds better if light (not too many people or fuel) and runs about 31 mph but feels like it is "pinned". As the drives get raised and the rpms go up all hell breaks loose - noisy, chaos, sounds like it is going to break apart but I can get a little over 4000 rpm and 40 mph....very unsettling and fule consumption jumps (I have navman gps and fule flow meters). Getting .8 MPG at 25.
My strategy going forward is two fold: I am hunting for smaller props, preferably cleavered 4-6 blades in the 17.5x21 range to see if I can get rpms up and get more into the HP of these motors. I am also playing with ventilation snorkels to help lessen the load at launch.
Second; I am looking to add blowers (small ones with 4 pounds of boost) to get another 75-100 HP and if I blow the motors -oh well - opportunity to get them built right and know CAM, roller, 4 bolt mains, Gill exhausts...not sure what the compression is so might have to change heads or pistons to lower compression since I want to run this thing on pump gas.
The props have been cupped, balanced, and changed to 19x19 but I am trying some other props since I cant seem to get more than 4100 rpm out of them.....would prefer 4800....and will keep these as spares if I find something better.
Steve in WA is the only other Harley owner I have ever spoken with and he has been very helpful with ideas.
The boat originally had 500 hp farera (NJ) 454s and the props were 20x23 pitch (3 blade nibral round eared low rake and no cup). When I purchased it it had been on a lift in Florida for 10 years as a project boat with blown motors that could not be repaired - the thread below shows what we went through:
http://pg.photos.yahoo.com/ph/orena...=&.done=http://photos.yahoo.com/ph//my_photos
I made one major mistake in the entire process, I decided that I needed 425 HP and since one motor was counter-rotating that I would go with 502's with carbs to keep things simple. I chose a guy in Ft Lauderdale to build the motors (instead of finding new ones) and though his references checked out he has a crack problem, flaked out and built two POS motors. I can't sue since there is a line in front of me and he has nothing to make good. So, after three rebuilds and many component changes she now runs okay but is under powered. How Steve can run his with 415hp stock motors is a mystery...mine is a dog.
Transmissions are 1.5:1 Borg Warners and I have Arneson ASD8s. She will cruise at 25 mph at 3600 rpm but doesnt sound good - working too hard and guzzling gas. At 3800 it sounds better if light (not too many people or fuel) and runs about 31 mph but feels like it is "pinned". As the drives get raised and the rpms go up all hell breaks loose - noisy, chaos, sounds like it is going to break apart but I can get a little over 4000 rpm and 40 mph....very unsettling and fule consumption jumps (I have navman gps and fule flow meters). Getting .8 MPG at 25.
My strategy going forward is two fold: I am hunting for smaller props, preferably cleavered 4-6 blades in the 17.5x21 range to see if I can get rpms up and get more into the HP of these motors. I am also playing with ventilation snorkels to help lessen the load at launch.
Second; I am looking to add blowers (small ones with 4 pounds of boost) to get another 75-100 HP and if I blow the motors -oh well - opportunity to get them built right and know CAM, roller, 4 bolt mains, Gill exhausts...not sure what the compression is so might have to change heads or pistons to lower compression since I want to run this thing on pump gas.
The props have been cupped, balanced, and changed to 19x19 but I am trying some other props since I cant seem to get more than 4100 rpm out of them.....would prefer 4800....and will keep these as spares if I find something better.