Correct Prop

[Wyatt53]

I have a 21 ft Tracker Fishing Barge what is the correct prop for this boat. I have a 90 Mercury. My rpm hit the rev-limiter and the dealer changed the prop and it still goes above 6000 rpm and it has slowed my speed from first prop.

 

[EGlideRider]

Re: Correct Prop

Lots of posts here about props..... You have no choice except to go up again until the R's in the proper range.

 

[Wyatt53]

Re: Correct Prop

There got to be someone on this forum that has the same boat with the same set up 21 ft Tracker with a 90 mercury Optimax

 

[lmuss53]

Re: Correct Prop

There is really a lot that could be going on with your boat. It is not as simple as "which prop?". If I had to give you a quick answer I would say 13p or 15p. You should take the time to find out how the prop works and what can impact how it works. I have a feeling your prop is letting go of the water, hence the rev limiter. If that's the case you need less pitch not more.

 

[lamac]

Re: Correct Prop

I have the same boat with a 90 4 stroke. Props gave me problems too. I am now on my third prop a 15 degree SS with two people onboard moves pretty fast. I got up to 30 mph as per GPS but was steady at around 29 mph. Put two more adults and a full tank and I only get around 24 mph. I have not used this prop pulling tubes yet. I also have a 13 degree prop just in case. The dealer suggested the 15 degree prop.

Good Luck

 

[EGlideRider]

Re: Correct Prop

Don't select your prop based on speed, only on the manufacturers suggested RPM range.
To answer your question more specifically, add 2 inches of pitch to the prop you now have.

 

[newtoon]

Re: Correct Prop

I have a Fishing Barge 21 with an Optimax 90. Mine came with a 15p aluminum. It would over-rev by a hair with just me, was ok with 2 or 3, and was lugging something awful with all the kids and toys. I talked to the local prop guy and tried his suggestions. I still run the 15p most of the time but when I get everybody aboard, I run a 13p with extra cup. That gets me back up to 5500 rpm and pulls a tube decent. I haven't tried a stainless. Too many sticks, logs and shallow spots in the lake. I think I'm getting about everything the little 90's got to give.