1970 19'6 aquasport what prop should i use

[jake69442]

i have a 1970 19 6 aquasport w/ a 1985 merc 90 hp what prop should i use the boat is only getting to 4700 rpm

 

[Dhadley]

Re: 1970 19'6 aquasport what prop should i use

Is the motor running properly? What pitch prop are you running now? What style prop? What's the set up like?

Normally we run either a 13 1/4 x 15 or 17 with that basic set up. A lot depends on your set up and intended use.

 

[jake69442]

Re: 1970 19'6 aquasport what prop should i use

yes motor runs properly,, i will be using the boat primarily for fishing and tow the kids on a tube occasionally,, as far as whats on there now i dont know it came with the boat i will get the numbers off it tonight

 

[jake69442]

Re: 1970 19'6 aquasport what prop should i use

ok got a chance to go out tonight with an inductive tach and im at 4500 to 4600 at wot, the numbers on the prop are 13.75 x 15 this is a standard center console with nothing other than the motor and one other guy holding the meter.. i replaced all electronics on the motor because of previous ignition problem and the motor runs on all 6 cylinders and has excellent compression im not sure where to go from here... is it a prop problem or maybe the previous owner of motor and boat screwed with the adjustments of the cables ?????????????

 

[Dhadley]

Re: 1970 19'6 aquasport what prop should i use

Is this a 4 blade prop?

 

[hwsiii]

Re: 1970 19'6 aquasport what prop should i use

Jake, how fast are you going with that prop.


H

 

[jake69442]

Re: 1970 19'6 aquasport what prop should i use

its a 3 blade and im almost hitting 30 mph on the gps

 

[jake69442]

Re: 1970 19'6 aquasport what prop should i use

at 4600 rpm i get to almost 30 mph going by my gps would going to an 14 x 11 pitch be too much to get closer to 5500 rpm the pitch is now 15 and would i loose top end speed or will the additional rpms make up for that

 

[jake69442]

Re: 1970 19'6 aquasport what prop should i use

i looked at another posting with a similar problem and went to look at the butterfly flaps @ wot there is almost 1/8th of a turn more i can push them open till they are wide open could this be part of my problem ?? is it safe to adjust them more there is a set screw on top of the top carberator that looks like it can be adjusted its where the cam hits the roler to open the carbs

 

[Dhadley]

Re: 1970 19'6 aquasport what prop should i use

I would say you hit on something important. Get the sync-n-link squared away and test again. Kinda important to have the motor running correctly....

 

[jake69442]

Re: 1970 19'6 aquasport what prop should i use

yep linkage was way off only getting 3/4 throttle i will test boat friday and start over

 

[jake69442]

Re: 1970 19'6 aquasport prop problem / fixed linkage

Re: 1970 19'6 aquasport prop problem / fixed linkage

ok i took out for a ride and now get 4900 rpm @ wot and almost 32 on gps i also replaced the fuel pump with an electric one rated 4-8 psi im wondering if its enough fuel? i will put a fuel gauge in line to see what actual pressure is @ wot . does any one know what i should have for pressure. i just want to make sure everything is running correctly before i start spending money on props if thats not my problem

jake