What pitch prop

[roughrider123]

I have a 90 overnighter with 140 suzuki 4 stroke using a 3 blade 14 - 18 Ss prop and it does not get close to max rpm topping out at 5200-5400. I'm thinking of a 4 blade 14-15 or 16. 200 hours on strong motor, no trim tabs and transom mounted.Any comments?

 

[LeapFrog]

The folks at PropGods were very helpful when I changed from a 3 to a 4 blade prop... I was actually able to keep a 17 pitch even though traditionally you need to drop an inch or two...
I mapped out my speed and rpm's before I called them and based on that we were able to decide on the powertech 4-blade 17's..
Love them! Most importantly the engines are running in the RPM range where they need to be and then the bonus of nearly 10% increase in mpg... 1.1 up to 1.2 isn't much at cruise, but every bit helps! Handling at cruise improved and slow speed trolling was much more stable.

 

[Doc Stressor]

17" pitch is too much for that boat and engine.

I blew up a 140 hp engine on my old 204C swinging a 17" prop. The boat performed OK with 2 people on board but the engine overloaded when hauling scuba divers and gear. After rebuilding the powerhead, the rig ran much better with a 15" prop.

 

[LeapFrog]

Didn't mean to imply a 17 pitch for the OP's boat... that was what I used on my Marlin... I was able to stay with the same pitch because I was on the top end of the RPM range... with the extra lift of the 4 blades, I squeaked out a few additional RPMs as well so I could stay with a 17 and hit the middle range...
I would agree that for his boat, a 15 pitch sounds like it would work very well for him...