Back to the main site

Where did my speed go?

R

resauter

Member
Messages
5
Reaction score
2
2011 2275FSi, Yammy 150
One day, the boat was comfortably running 35 mph at wide open throttle (about 5850 RPM). No prop strikes, or obvious damage to the prop, and next trip out, with just two extra people on board, suddenly I can’t get over 25 mph!
It feels as though the boat is dragging, and the prop is either cavitating, or experiencing ventilation.
I have a hard time imagining that 400 pounds of additional people, same fuel load, all else, and my speed suddenly dropped by 10 mph. By the way, RPMs are still running close to 6000 RPM.
Questions: does the F150 have a rev limiter? I feel as though I’m sitting on the rev limiter rather than the prop holding the rpm’s at the correct place.
Any ideas on what might have so suddenly changed without having struck anything and damaged a propeller?
I checked the boat on the trailer, and we are not dragging a tree stomp, or an anchor, or anything like that!
 
Dirty toons ? Even light slime will slow you down.
 
Any chance you have bad gas? When was the last time fuel and water separater filters changed? Does the engine feel like it is firing as normal or maybe time for new spark plugs?
 
Change fuel water separators just to be sure. My Yamaha 250 SHO is supposed to run 6000rpm max but I hit 6200 without it limiting me. My Verado had a limiter, doesn't seem like the Yamaha does.
 
Fuel water separator changed in October before putting the boat away for the winter. Engine is not misfiring at all. Tunes are not as clean as they could be, but they’re cleanliness did not change from one outing to the next outing five days later.
 
If your prop has a pressed-in hub that is slipping, it won't last long. Stay below the slip point to prolong the use.

Has the boat run a better speed with that load previously? Where was the 400 pounds, if only in the back, that could be the problem. How are you checking the speed? boat speedo or GPS? The problem could be load distribution and a prop not well suited to pontoon operation.

You motor should have a rev limiter, expect it to be more in the 6200-6400 range.
 
Load (400ish lbs of people) was distributed evenly throughout the boat.
The speed is GPS speed, I do not have a in water speedo
As stated in my original post, nothing else had changed from previous outings with this boat, and the speed suddenly dropped by 10 mph. The prop is the power matched Yamaha prop for the boat, and until recently worked fine.
I think NCLakeguy has probably nailed it. I will pull the prop and put our spare prop on and then water test the boat.
Thank you all for your replies. While I have owned boats for 50 years, this is our first pontoon, and only about our 10th or 12th outing with the boat so I am still learning.
 
You must log in or register to reply here.
Back
Top