short 1000 rpm

[jonesy cc]

this may be lenthe .I have assembled a 1972 chris craft 25ft. catalina . Ibought it for 500.00 $ and take that junk boat next to it, cracked 4,3l rotted cobia . the chris craft had no motor was a 307 chevy . I had a 4.3l no marine parts on it so I made a marine 4.3l . I ran into a few problems wrong rotation turned the trans pump plate to left now has a left swinging prop. works fine .it only turns 3200 rpms Ihave tried 2 propes 14x10 and 12x11p to no affect on rpms changed the speed by 4 mph ,now left propes to try are scarce . I have tried timming ,carb adjustments . is it possable that the 4.3l just doesnt have enough tourque to turn things any faster ? or is there a gouvner in the paragon trans.? oh the boat weighs between 6000-7000 lbs. not shure, hard to trailer a 10ft. beam to scales. Also checked the tach. against a dvomm. matched

 

[Bondo]

Re: short 1000 rpm

this may be lenthe .I have assembled a 1972 chris craft 25ft. catalina . Ibought it for 500.00 $ and take that junk boat next to it, cracked 4,3l rotted cobia . the chris craft had no motor was a 307 chevy . I had a 4.3l no marine parts on it so I made a marine 4.3l . I ran into a few problems wrong rotation turned the trans pump plate to left now has a left swinging prop. works fine .it only turns 3200 rpms Ihave tried 2 propes 14x10 and 12x11p to no affect on rpms changed the speed by 4 mph ,now left propes to try are scarce . I have tried timming ,carb adjustments . is it possable that the 4.3l just doesnt have enough tourque to turn things any faster ? or is there a gouvner in the paragon trans.? oh the boat weighs between 6000-7000 lbs. not shure, hard to trailer a 10ft. beam to scales. Also checked the tach. against a dvomm. matched

Ayuh,.... Welcome Aboard, Jonesy...

Obviously, I ain't got anymore answers fer ya,...
But,...
I'll see what I can find out....

 

[Don S]

Re: short 1000 rpm

I think one of your biggest problems is the size of the boat and the size of the motor. Even the 307 sounds boarder line.
Put that with the wrong gear ratio in your tranny and I can't see you ever getting the rpm's to normal.
You probably should start looking for a 5.7 for that size boat

 

[jonesy cc]

Re: short 1000 rpm

is the hourse power close 307 185-190 HP. 4.3L 160-225 HP or is it a tourque thing ? I also like 6 gal. per day . can the ratio be changed with out trans change? she will run 27mph at 3200 Idont fore see much more with a 350 .