What prop??

[moeouellette]

i had my boat out today,its a 2001 lowe 16.5ft side console fishing boat,with a 75 honda bf75.4 stroke
i just put this engine on and after fine tuning and adjustments the best i can get is 3900 for rpm.i have a 13 1/4 x 17 three blade aluminum prop.the recommended RPM is 5000-6000.
Any recommendations on what to bring up my RPM,what size/pitch prop should i have?
thanks.

 

[solar7647]

Re: What prop??

IF it is a prop issue you need to bring your pitch down. For every inch you come down in pitch the rpm will go up 200-300rpm. If you call West Marine or Bass pro or any marine store that does engine work and sell parts, they should be able to tell you what Handa recomends for it. start there if yor not in your WOT range with the prop they suggest you may have a bigger issue. I know the manufactures solution to picking prop isnt perfect but it is a good place to start from. Good Luck

 

[quackaddict1]

Re: What prop??

Where is the cavitation plate in relation to the bottom of your boat? If your dragging a ton of stem in the water you will loose RPM's, my 28hp was some 3 inches low before I installed a jackplate, I picked up 400 -500 rpms but just getting the height right.

 

[moeouellette]

Re: What prop??

the cavitation plate is equal with the bottom of the boat,maybe 1 inch below.
might be a dumb question but.....i upgrade from a 40 hp honda to the 75 honda.all electrical connections were the same.will the tach still be accurate?

 

[hwsiii]

Re: What prop??

Not always.

H

 

[steelespike]

Re: What prop??

the cavitation plate is equal with the bottom of the boat,maybe 1 inch below.
might be a dumb question but.....i upgrade from a 40 hp honda to the 75 honda.all electrical connections were the same.will the tach still be accurate?

If the number of cylinders is not the same the tach may need to be set differently.

 

[moeouellette]

Re: What prop??

i checked rpm and at 2000 rpm it was off by 1200 rpm.there's my problem,but do i need a new tach or can this one be set up to work.i had a 3 cyl now i have a 4 cyl.

 

[steelespike]

Re: What prop??

I would think there should be a setting for a 4.The number for a 4 cylinder
may not be 4.Make note of the setting for the 3 you may be able to deduce the setting for a 4.Or of course you could check with the dealer.