This spring my family purchased a new 26' pontoon boat with the 115 hp pontoon series motor
Model # E115SNLAFA
Prop 15.5 *11
Prop # Evinrude 767620
Our problem from day one is when the boat is loaded down with 10 or so people we loose RPM's after we get up on plane.
From WOT which is 5400 it looses a thousand RPM .
Put 2 or 3 people on it, it maintains the RPM.We have also noticed how poor our fuel consumption has been.
We took it back to the dealer twice, he plugs it in and says everything looks ok but all it shows is how many seconds the engine runs at certain RPMs .
I know there is such thing as prop slipage but how do you identify it?
We asked our dealer for a Stainless Steel prop but he told us they do NOT make one for our engine.
The dealer first gave us a 15.5*13 prop but our RPM only maxed out at 4800. So we went with the current prop.
07-09-2015 02:12 - edited 07-09-2015 02:25
There is a stainless steel SSP propeller in a 15-5/8 X 11 number 763959 but with your top rpm of 5400 you may need an even smaller pitch prop to get the revs up near 6000 with a light load. That way the motor will not be lugged down when you bring a group of people on board.
I looked for other brands of propellers in a smaller pitch but 11" was the smallest available. If the SSP 11" does not get the revs up near 6000, then you may need the services of a good propeller repair shop who can re-pitch the blades to about a 9" equivalent.
The 115 requires high revs for the exhaust tuning valve to operate efficiently. Getting the rpm up near the top of the operating range will allow the motor to run better and should help fuel economy and lessen oil usage somewhat.
There is a software update for certain Evinrude E-TEC 115 HP engines to alleviate some rpm dropoff. See your dealer to find out if the update would apply to your particular motor.
09-28-2015 09:31 - edited 09-28-2015 09:34
I had the same problem from day 1 with our rpm (same engine as you). Dealer first gave me the 15.5x13 which my rpms were around the same as you 4800.
The dealer was no help for me and there answer was its cause of the break in period to which I knew there was no break in period with these engines. Goes to show what the dealers know lol.
I also had rpm drop off approx 1000 with that 15.5x13 prop.
I then got a solas prop 15.5x11 which brought my rpms up to between 5600-5700 at WOT with light load and no RPM drop offs.
I recently bought and tried the evinrude one you speak about the 15.5x11 and rpms range 5500-5600.
I have never been able to achieve highter then 5700.
My next venture is to attempt to play with the height of the engine.
Have you figured your RPM's out??
10-21-2015 07:06 - edited 10-21-2015 07:08
Have a 2015 Bennington 22 with a 115 Pontoon Series. Exact same problem. Dealer was baffled by problem. This forum got me to suggest going from a 13 to 11 pitch. Helps a lot. Should be a notice to all owners of these engines. Sure there are many out there that are not aware of the simple fix. Why are so many being shipped with the wrong set-up?
We are happy to hear that your motor is performing as it should. We do feel bad that it was not propped correctly when you first received it.