WOT only 3500rpm

[pontoonwad]

I am new the boating world and just wanted to ask a couple of questions so please excuse my ignorance.

So, we got a 2003 20ft Pontoon with a 2002 40hp 2-Stroke Mercury and when we drop it in gear and cruse down the water it runs about 12-13mph and at WOT the max rpm is 3500. Now, take it out of gear and rev the motor and it will go to 5500rpm WOT. I am guessing the difference we see is because its under a load or should the motor still go above 3500 rpm when in gear and going do the water. It can be one person in the boat or 4 its the same.

Thanks in advance,
Wade

 

[alldodge]

Pontoons are not that efficient but with only getting 3500 I would look at trying a prop with less pitch. What size is on it now?

 

[Scott Danforth]

how low is your motor? too low and it can lug

you are correct, very little effort needed in neutral compared to being under load

like AD said, drop down in pitch.

 

[jimmbo]

Is it firing on all cylinders?

 

[pontoonwad]

I am not sure what size prop is on it now, and as for as firing on all cylinders I believe it is. We have not taken it in anywhere since we just got it Sunday and don't have a trailer to get it anywhere yet. We barrowed a trailer to get it to the river and a friend has a dock they said we could use so its in the water. I am thinking is also at the right height not sure since it looks like it sits ok the only thing we did notice is that there is a gap between the transom and motor bracket. I got a trailer yesterday but it needs some bunk work before we can put it on and take it in. As far a making sure its firing on both cylinders could I just get it running and pull a plug wire to see if each one is at least working or is that not a good idea. And again thanks for the information.

Wade

 

[johnboy3]

I am not sure what size prop is on it now, and as for as firing on all cylinders I believe it is. We have not taken it in anywhere since we just got it Sunday and don't have a trailer to get it anywhere yet. We barrowed a trailer to get it to the river and a friend has a dock they said we could use so its in the water. I am thinking is also at the right height not sure since it looks like it sits ok the only thing we did notice is that there is a gap between the transom and motor bracket. I got a trailer yesterday but it needs some bunk work before we can put it on and take it in. As far a making sure its firing on both cylinders could I just get it running and pull a plug wire to see if each one is at least working or is that not a good idea. And again thanks for the information.

Wade

I would think pulling plug wires would be an easy way to tell. My pontoon just did a very similar thing as yours except I was running only 2200 RPM and maxing out at 6MPH (mine is a 90HP). I checked spark and only had 2 cylinders running and then shortly after only 1 cylinder and then none would fire. Mine ended up being a stator going out.