I have a 2009 2275 RLi series two tube with a 2009 115 merc. The motor is mounted in second hole from as low as it can go. I am running a Black max (77340A45) 13 pitch prop. Problem being is i cannot get optimum RPM with this set up.... I see alot of people swear by this prop with this size benny. When i trim past 25% it will blow out and at 25% trim i am only at 4900-5000 rpm. optimum for this motor is 5800-6400! Max speed i have seen with my wife and kids with 1/2 - 3/4 tank of fuel is 23-24 mph. I also notice that the front will never really come down once at speed. So i guess my question is do i raise the motor a hole or lower it a hole to as low as it can go? I know this subject has been beat to death!! I have spent hours searching for an answer with no luck!
Right Prop Wrong RPM!!!
- Thread starter Badmofo
- Start date
Michiman
Well-Known Member
Yeah, you need to get your RPMs up but as you increase pitch you decrease RPMs. I'm no expert but you may need to move your engine height and/or change the diameter of your prop.
cwag911
Moderator
Do you have strakes?
cwag911
Moderator
That'll make a huge difference in performance.
2fast4u
Well-Known Member
you may have partial clogged fuel injectors not letting your motor make max HP . Prop pitch seems about correct to me. My 2250 gl twin toon no strakes, turns 6000 rpms with a 115 yamaha and a 13 1/2 X 13P prop @ 28 mph
Alicedream
Well-Known Member
I had same boat and set up as above and turned 6000 RPM and topped out at about 26 MPH
Never really thought of that. runs and idles perfect. but, boat only has 80 hours on it so has not been used much so with todays fuels that is very possible. I need to check where the AV plate is riding and add some fuel injector cleaner to the fuel!
2fast4u
Well-Known Member
best thing to do is remove the injectors and send them to a injector cleaning service place. they can flow test them and clean them and then re test the cost is only $15 to $20 per injector Fuel Cleaners will not clean the small fuel filter in each injector. This is a must do for marine engines every 4 to 5 years,
cwag911
Moderator
Our Honda is 12 years old and I've never cleaned the injectors. It still runs like new. Only changed plugs once and they also still looked new. (iridium)