Sun Tracker Prop

[reddog]

Hello, I have 22 ft Sun Tracker 22 foot pontoon boat that has a 2009 Mercury 90 efi motor.
The 2 pontoons have lifting strakes on them.
I have not changed the prop before. Still using the one that came with it.
I do not know what pitch prop is on the boat.
**stamped on prop is 77340A45P13
The boat will pull a skier and a tuber but could use a little more help in that area.
Currently the boat is used mainly for fishing, cruising. It will go 29 mph with just me in it.
Put 4 bodies on it and it will go 24 mph or so. Loaded and pulling a tube it may go 20-22.

What is the prop I should put on this boat. I was thinking about a stainless. When I run the prop checker I get mixed results.
One said a 14x11 and another said 14x13. Do any of you have a similar ride and can help me pick a new prop.

Thanks

[mzodarg]

Your current prop is a 14x13P. When your running at 29 mph, what rpm are you pulling. I currently have a 2015 fishing barge with a 90 hp Command thrust.

Your speed examples don't sound to bad to me, exceptional if you just have 90 non command thrust.

Let us know what your max rpm is.

Mike

[reddog]

Max RPM's is about 6000 with just me in it.
With 4 people closer to 5000.
It really lugs and lags when pulling a tube in a turn.
Just wondering if going from a aluminum prop to stainless would help out.
Not really trying to go much faster just get better performance out of it.
I think the lifting strakes do help with top speed.

[Maholli]

Sounds like its alittle over propped. Have u tried 4 blade?

[Maholli]

From what i understand you dont benefit that much going to stainless with a 90hp.. U might wanna go a pitch lower when u do water sports.. I have 4 blade with same pitch as my 3 blade i use when i use it for water sports.. The 4 blade with same pitch is actually like going down in pitch with a 3 blade.. So what im saying is go a pitch lower with 3 blade or same pitch with 4 blade. Ur rpms need to come up with people in boat..

[Bamaman]

You maybe just experiencing the limitations of a 2 toon boat. When you take a tight turn at higher speeds, the outside toon digs into the water deep, and speed is bled off badly. You've got to throw the throttle to get it back up to speed.

The best way to making a 2 toon boat more seaworthy is just to over-horsepower the boat, but that's not always more practical. It sounds as if you have about the right prop.

An option would be to send off your ECU to have it reprogrammed for maximum horsepower and improved driveability--$650 at Simon Motorsports.

[teecro]

Max RPM's is about 6000 with just me in it...

Considering that you have never done any prop work I'm going to assume that is the OE prop and that since it is a 14" that you do not have a CT lower end.

Given the info you've given it sounds like your propped just about as good as it gets for overall performance as 6K is going to be the max recommended RPM with a light load.

With that being said at what height is your motor running? Sometimes there is some extra speed to be found by raising the motor one hole; which cost absolutely nothing to try.

Many folks keep an extra prop on hand with less pitch to switch to when the load is heavy or pulling a tube/skier...

As to stainless verse alum and speed. While stainless has less flex and thus less loss in thrust you may not see much if any improvement as your already getting along pretty good for a 22 foot twin with only 90 HP... As a reference my 75 was tried on an 11P & 13P both in 3-Blade and 4-Blade and while the 3-Blade got me more speed than the 4-Blade I ended up with the same speeds receptively with the 11P & 13P just different RPM. I did find an extra couple MPH in a 12P stainless prop.

[mzodarg]

Max RPM's is about 6000 with just me in it...

Considering that you have never done any prop work I'm going to assume that is the OE prop and that since it is a 14" that you do not have a CT lower end.

Given the info you've given it sounds like your propped just about as good as it gets for overall performance as 6K is going to be the max recommended RPM with a light load.

With that being said at what height is your motor running? Sometimes there is some extra speed to be found by raising the motor one hole; which cost absolutely nothing to try.

Many folks keep an extra prop on hand with less pitch to switch to when the load is heavy or pulling a tube/skier...

As to stainless verse alum and speed. While stainless has less flex and thus less loss in thrust you may not see much if any improvement as your already getting along pretty good for a 22 foot twin with only 90 HP... As a reference my 75 was tried on an 11P & 13P both in 3-Blade and 4-Blade and while the 3-Blade got me more speed than the 4-Blade I ended up with the same speeds receptively with the 11P & 13P just different RPM. I did find an extra couple MPH in a 12P stainless prop.

I was thinking the same thing!

[brumbyvet]

The best all around prop I've found is the Mercury 4 blade. I forget the name of the prop at the moment. but it performs much better then a three blade, with more then 2 people in the boat. With a lighter load the 3 blade was faster. It sounds like our boats are very much alike and with the 4 blade I can run 33 mph with 2 in the boat.

[teecro]

The best all around prop I've found is the Mercury 4 blade. I forget the name of the prop at the moment. but it performs much better then a three blade, with more then 2 people in the boat. With a lighter load the 3 blade was faster. It sounds like our boats are very much alike and with the 4 blade I can run 33 mph with 2 in the boat.

Likely the Mecury Spitfire... Too I found that while the overal performance with the Spitfire including turns and towing was a little better than the Black Max 3-B blade. But since I tow the least and want to have as much speed as possable to have the option to cover more distance on our huge lake that the stainless 3-B suited me best....

BTW If any one is interested in an Alum 4-Blade 13.8" Diameter x 11" Pitch Mercury Spitfire with not a lick of paint worn off let me know....

[reddog]

Thank you for your input.
I do not know what CT lower end means.

Sounds like I should try a 4 blade prop for use when doing water sports and leave the 3 blade on the rest of the time. Water sports is not an every week thing but fishing usually is.
I bot the boat used but the guy I bot it from would have put OEM back on if he had to replace.
He didn't use the boat at all, it was like brand new when I bot it last year.

[teecro]

Thank you for your input.
I do not know what CT lower end means.

Sounds like I should try a 4 blade prop for use when doing water sports and leave the 3 blade on the rest of the time. Water sports is not an every week thing but fishing usually is.
I bot the boat used but the guy I bot it from would have put OEM back on if he had to replace.
He didn't use the boat at all, it was like brand new when I bot it last year.

Sorry CT stands for Command Thrust and on some motors also called Bigfoot... On some units Mercury likes to install the lower end from the next class of motor. This allows them to swing a bigger prop with a smaller motor which is really good on Pontoons and other heavy boats. They did this with the 40/50/60 motors with a 75/90/115 foot and again on the 75/90/115 with a 150 lower end.