and one more time

[cuzzx]

and this is it, I'm tired of this.

Ok, I have a older 20ft pontoon with a older Mariner 75hp running a 13 3/4 x 15 aluminum prop. This is what the toon/motor did today.

Toon weights about 1200lbs, motor is 280lbs. two men at 375lbs. gas 10gals. and gear around 50lbs.

motor at WOT 4200rpm/15mph

3300rpm/11mph

2600rpm/7 mph

2200rpm/4 mph

setting in the water the motor's cavitation plate is about 4inches below the water line, with the motor running at WOT you can see the bolt that holds the trim tab at water level.

What do you think needs to be done to get R's up and speed right?

 

[CharlieB]

Re: and one more time

How clean is the bottom, growth SERIOUSLY creates drag.

How old is the fuel? Spark plugs?

How clean are the carbs?

How much compression?

Test stator output with a DVA Meter.

Any one or a combination of the above will reduce speed/rpm.

Start with the easy, any go from there. If compression is low testing with a quality tool, (cheap ones may not give an accurate reading) the cost/benefit of a rebuild may exceed the value, same if the stator test low output.

Still, 4200 pushing a toon is respectable.

My 1st inclination is a dirty hull.

Clean with The Works brand toilet bowl cleaner, soak it and let set 30 minutes then hose off. If you want to remove all the stain then wet with AlumaBrite, FULL strength and hose off BEFORE it dries.

Wax will prevent the rapid regrowth and 'slicken' the surface for a couple of weeks.

Pure elbow grease, and LOTS of it.