could changing my prop increase gas mileage? example: a small prop and a bigger one at the same speed, would the bigger one not be at a lower rpm? hence better gas mileage?
P.S. This may be something most people already know and im just gonna get “hey stupid!” answers but oh well. I have faith that most people on this website are intelligent, kindhearted people, and not immature high school kids that make them selves feel better by cutting others down.
Would give you a little better gas mileage but will take longer to get on plane. I also run high rpm at cruising speed. Have thought about changing mine also.
Key West 1720cc
Yamaha f90
I would be willing to sacrifice some getty-up and go for some better gas mileage. atleast when i go offshore.
23’ May-Craft Pilothouse
175 Ocean Runner
http://www.brookssigns.com
Stilletto Bay Pro II 13 1/4" X 15" pitch is a 4 blade stainless steel prop that would fit your 175 Ocean Runner. It will get you on plane faster, thereby saving gas by not having to push water for so long. Gives you the power of a 17" pitch without increased RPM. They ain’t cheap, $500 or so but you can find them discounted down to about $300.
Dave
Pawleys Island
I just went through all this with my boat. Factory says WOT Max RPM for my engine is 5400-5700rpms and I was turning 6300rpms. I had a 19P and dropped back to 20P and had an aggressive cup put in it and now only turn 5200 at WOT. I am going to have some of the cup taken out and think it will be dead on the money then. Local prop shop can do all this for you. Did mine for $40 each in Columbia. You need to know what your factory WOT RPM range is first as a starting point.
Rick
cool! thanks for the advice guys. Does that 4 blade prop interfere with top end speed and rpm?
23’ May-Craft Pilothouse
175 Ocean Runner
http://www.brookssigns.com
Do you know were i could find info online like WOT rpm range and so on. I dont have any info like that on my motor.
23’ May-Craft Pilothouse
175 Ocean Runner
http://www.brookssigns.com
the only prproblem with over propping your boat is that if you cant get up to high enough rpms at wot then it could cause your engine to load up and build up carbon. find out what your rpm range for your motor is and try to find a prop that will be towards the lower to middle end of that range.
197 poineer F150
Over propping could also potentially lead to blown head gaskets. Have heard of several instances where motors were lugging (too much prop), and gasket failure occurred. It might take some trial and error to find what works for motor/load/speed/fuel but seems like you have good advice already.
“If you’re not a liberal at twenty you have no heart, if you’re not a conservative at forty you have no brain.”
First and foremost when propping a boat, you want to make sure the engine can attain the manufacturer’s WOT speed range.
Second is that you want to make sure the prop is moving the boat efficiently, i.e. jumps it up onto plane well, stays hooked up in turns and heavy weather, gives good economy, and in generel is within the 10-15% slip range.
Third is worrying about speed.
If you follow the steps and do get to step three you will have a good prop. Going out of order will likely result in you not being happy and/or the engine won’t either.
Iain Pelto
Edgewater 185CC “Jumpin’ Bean II”
Native Manta Ray 14
ok. well thanks for the advice everyone, i wont be jumping into buying a bigger prop and just throwing it on there to see what happends now. I may research other ways to better my gas mileage before changing the prop.thanks again
23’ May-Craft Pilothouse
175 Ocean Runner
http://www.brookssigns.com
What is on the motor now? what are you turning at WOT??
No one knows if YOU are THE village IDIOT or not until YOU open your mouth and speak!!!