Too little power to go faster?
Posted: Sat Jun 02, 2018 7:24 pm
OK, major newbie questions......... I signed up here after perusing the board for a long time, because I see a style that suits me! I now own my first pontoon. AND my first outboard.
It is an older 25' 2000 Crest II DL, powered by a Yamaha F115 4 stroke. Upholstery, carpet and Bimini top are in great shape because the boat saw very little use (189 hours) and had been sitting covered on a sling sitting in the boat house for 3.5 years. It lived at a weekender lake house that I bought. Mildew was NASTY but Marine 31 always works.
I replaced the water pump impeller, changed the lower unit oil, the crankcase oil and filter, new spark plugs, both fuel system water separator-filters and air intake. While flushing out the fuel system, I was forced to redefine my personal definition of "bad gas." Oh Wow.......I had no idea!!
I was expecting to change the injectors (the first year using EFI for this motor) but they started firing great after 1/2 to 3/4 gallon of fuel heavily laced with injector cleaner. My test for this is to slap to full throttle from idle, in gear. If there is NO (I mean zero) bog down or hesitation, I'm good to go.
So, realizing that my frame of reference is 40+ years of offshore boating in the Pacific - and I understand that I don't have a planing deep V hull, but...... I feel like I am plowing, no matter what I do. The front of the pontoons never get up in step.
WOT with with four adults and four kids, speed measured by GPS: 24-25 MPH at 5800 to 5900 RPM 6000 is maximum rating.
If I trim up, it quickly ventilates and the bow never rises. If I trim down, I can clearly feel the plow and I lose speed first, then RPM, then steering.
Other data points
4500 RPM is 16 MPH @ 5.8 GPH
3000 RPM is 12 MPH @ 2.6 GPH
The layout is full couches all the way around, so it is front heavy. The bow sits high when sitting in the water - about the balance that I would want to see based on experience. I do not know what the prop is yet - I was focusing on getting her running healthy for the Grandkid visit!
My instincts tell me "all is well" I am simply under powered for for the weight,size and pontoon tube design. Is it possible that the prop needs to be lower in the water? Or should this boat have a 150+? Picture of the pontoon profile is below.
Thoughts are welcomed!
Marc
It is an older 25' 2000 Crest II DL, powered by a Yamaha F115 4 stroke. Upholstery, carpet and Bimini top are in great shape because the boat saw very little use (189 hours) and had been sitting covered on a sling sitting in the boat house for 3.5 years. It lived at a weekender lake house that I bought. Mildew was NASTY but Marine 31 always works.
I replaced the water pump impeller, changed the lower unit oil, the crankcase oil and filter, new spark plugs, both fuel system water separator-filters and air intake. While flushing out the fuel system, I was forced to redefine my personal definition of "bad gas." Oh Wow.......I had no idea!!
I was expecting to change the injectors (the first year using EFI for this motor) but they started firing great after 1/2 to 3/4 gallon of fuel heavily laced with injector cleaner. My test for this is to slap to full throttle from idle, in gear. If there is NO (I mean zero) bog down or hesitation, I'm good to go.
So, realizing that my frame of reference is 40+ years of offshore boating in the Pacific - and I understand that I don't have a planing deep V hull, but...... I feel like I am plowing, no matter what I do. The front of the pontoons never get up in step.
WOT with with four adults and four kids, speed measured by GPS: 24-25 MPH at 5800 to 5900 RPM 6000 is maximum rating.
If I trim up, it quickly ventilates and the bow never rises. If I trim down, I can clearly feel the plow and I lose speed first, then RPM, then steering.
Other data points
4500 RPM is 16 MPH @ 5.8 GPH
3000 RPM is 12 MPH @ 2.6 GPH
The layout is full couches all the way around, so it is front heavy. The bow sits high when sitting in the water - about the balance that I would want to see based on experience. I do not know what the prop is yet - I was focusing on getting her running healthy for the Grandkid visit!
My instincts tell me "all is well" I am simply under powered for for the weight,size and pontoon tube design. Is it possible that the prop needs to be lower in the water? Or should this boat have a 150+? Picture of the pontoon profile is below.
Thoughts are welcomed!
Marc