I have about an 1 1/18-inch clearance.
Never actually measured a prop diameter before not exactly easy. Ran the Mercury part number and the aluminum is a 14 1/2-inch diameter. The stainless is older so could not locate but pretty sure it’s the same diameter. I Don’t think a 17-inch is an option as far as clearance? There looks like some 15-16-inch options…don’t know how to go about determining what size to move up to?
I WOULD TRY A 15X21
JUST TO GIVE YOU AN IDEA OF PROPS, MY SON HAS A TILLER HANDLE JONBOAT, THAT HAS A 60 2 STROKE. IT HAS A 2.33-1 GEAR RATIO.
HE RUNS OVER 50MPH, AND SWINGS A 24 PITCH PROP AT 5300RPMS.
YES, I SAID 24 PITCH ON TILLER HANDLE JON BOAT, BUT THATS WHAT IT TAKES TO MAKE THE MOTOR RUN CORRECTLY.
www.teamcharlestonmarine.com
www.bombislandboats.com
IF I RESPOND IN ALL CAPS, ITS NOT ON PURPOSE, AND I AM NOT YELLING
quote:
Originally posted by contender1Palmer I sure hope you are wrong. I am thinking this may have been occurring since we installed a few years ago and I am starting to notice it now because I am more aware of it and because my kids are growing so the boat is more loaded and I am running in this range more often.
Chris the foot is stamped 13x32 not sure what that correlates to? Ratio looks to be 2.38:1
Prop is a Mercury 832830A45 P19 it is their aluminum prop. The stainless prop is a Quicksilver 48 16316 A5 19P
I’m not saying it is not the prop. I’m just saying I’m not convinced it is. Weird symptoms. Hard to get any real sense of what’s happening without hearing/seeing in person.
17’ Henry O Hornet w/ Johnson 88 spl
26’ Palmer Scott project hull
14’ Bentz-Craft w/ Yamaha 25
I’m not seeing that little adjustable trim tab on the anode right above and behind the prop. Too simple of a solution?
Good eye on “missing zinc” local but it’s there. Mercury uses a flat one there on this particular motor as opposed to one with a “fin” hanging down towards the prop like you usually see set up to offset the “ prop torque ■■■■■■■■” in steering.
Go to an Expert:
Skip’s III Propeller Service
AKA
PESCO. INC.
Propeller Equipment Supply CO Inc.
1-800-835-6007 and 843-767-8643
3333 N. American St., N. Charleston, SC 29418
mike@pitchblock.com
I hate when people ask for advice on a forum and never report back! I always try not to be that person. This has taken a little while to get resolved but believe I am finally there. I had an in-depth conversation with the guys at Skip’s as well as the guys at Oswald. At the end of the day they both told me I needed to talk to Marcus at power tech propellers. I got to say he certainly knows his stuff. Marcus ran numbers for me and as other stated before my slippage was in excess of 15%. Marcus recommended a 14 1/4 diameter 18 pitch 5/16 ported four blade ss prop with a cush lock set up. I ordered the prop a couple weeks ago and had the opportunity to install and run it through its paces last Friday. With the three blade prop I was getting to six grand without even trimming, the four blade has knocked it down to 5700 and I’m now able to trim to 6 grand and pick up another 1.5 knots from trimming. Before if I was running anything over five grand and slammed it down rpm’s would jump straight to six and then come back down as the prop tried to grab and slowly accelerate, with the four blade it does not ventilate at all it just accelerates. The boat also holds a corner significantly better with no ventilation and I am able to get up on plane at a lower RPM. Slippage is now calculated at approximately 8% throughout most of my RPM range.
I am still getting a minor amount of cavitation just as the boat starts to come up on plane if I accelerate extremely slowly; however the RPM range of the cavitation is now narrower and the intensity of the vibration from cavitation is far less. This is still a minor concern, Marcus has recommended messing with the trim angle of the motor during this time as well possibly the trim tabs. He also said to remote mount and get some go pro footage of the cavitation plate with the boat running in the 5 grand range as the plate ishould be about an inch above the water surface. If the plate is deeper in the water than that I may try raising the motor a notch and check performance then.