need help picking prop

[pontoondaddy]

Hello i need some prop advice i have a 25 ft pontoon with a 1979 eninrude 85 hp.I had it on lake it ran about 16 m.p.h thats full throttle with just 2 people on it .Need some help picking prop out on size and pitch. thanks for all help.

 

[Silvertip]

Re: need help picking prop

Read the sticky at the top of this page that is titled: READ THIS FIRST!! The data you provided is of little to no help. If you don't have a tach, we are just as much in the dark as you are as without wide open throttle rpm "observed" we can't help (much).

 

[steelespike]

Re: need help picking prop

Welcome,Your prop size is near the base of the blades or under the prop nut.
If you get us the prop size we can get you started but we will need the max rpm and speed to really solve anything.

 

[Maxz695]

Re: need help picking prop

wow 85 HP and 16 mph You need a smaller pitch prop but as stated without WOT RPM we can,t begin to give you a clue on proper pitch

 

[Miner49er]

Re: need help picking prop

Hey, slow down guys...you are going to scare us new folks away before we get a "grip" on what we are doing here on this forum. This is all new to me too ( pontoons that is).

When I first purchased my boat ( in February), I thought that it would be wise to purchase a second prop just in case I distroyed the one that was on the boat. The broker advised me to first figure what elevation the waters were that I was going to be boating in before investing in another prop.

Could this be maybe some of his problem...By the way, what is a "proper pitch". I've yet to hear that term. Thanks

 

[steelespike]

Re: need help picking prop

Some if us are a little rougher than others.But we'er here to solve your problems and get you on the right track.Please feel free to ask any questions as there are no foolish questions.
The "proper pitch" is that which allows the motor to rev freely within its rated rpm.
That pirtch depends on the application.
If you read the stickies at the top of the page and the helps on the prop store page it may help you understand prop selection better.Again feel free to ask us to help with any confusion.
I had my first outboard when I was 6 so have 62 years of practical boating experience.
And I've learned a lot just hanging out here.There are others with more technical knowledge
and we'll try to get everyone on the right track.

 

[Miner49er]

Re: need help picking prop

I hear ya. Your forum has already helped me wire my trolling motor, pick the right inboard charger and 50 amp braker.
I was just reflecting back to a Dodge Diesel forum that I joined 7 years ago. Those guys sometimes would get frustrated with me cuz I asked questions that they answered time & time again. I turned out to be the same well informed, frustrated diesel owner...
Maybe I can become an "old salt" too...Have to do a lot of crammin though, I'm 63 myself...

 

[pontoondaddy]

Re: need help picking prop

Sorry it took so long to get back on here just got pontoon back out on lake.I watch the tac on (WOT) it just turn 3000 rpm.Never found the size or pitch on the prop that on boat now looked all over it.Thanks for all the help...

 

[Bob_VT]

Re: need help picking prop

The 85 hp motor should be turning 5500 rpms at wide open throttle. If you are only achieving 3000 you NEED to verify WHY!!

You either have motor problems, maybe the tach is wrong, could be prop problems........ I know it is confusing.

When you are turning 3000 rpm at wide open throttle then that can be considered lugging the motor which is bad. Further investigation is required.

 

[steelespike]

Re: need help picking prop

Did you look under the prop nut for a number?An educated guess you need an 11" pitch.
A prop shop could measure your prop.If you allready have an 11 then we'll know you have a motor problem.

 

[Smuggler's Blues]

Re: need help picking prop

I think you guys are too hard on yourselves. I was on a cop forum, (I wont say which one), that if a "newbie" asked a question without using the search function they would do everything they could to get them to not come back. I dont spend a lot of time there any longer.

 

[pontoondaddy]

Re: need help picking prop

Did you look under the prop nut for a number?An educated guess you need an 11" pitch.
A prop shop could measure your prop.If you allready have an 11 then we'll know you have a motor problem.

i have looked all over the prop for any kind of numbers i cant find any at all.the motor and prop come off a 16ft walk threw window. i put it on my pontoon and left everthing on it so i dont know what pitch is

 

[steelespike]

Re: need help picking prop

You can be sure if the prop was right for the 16 its wrong for your pontoon.
You could have a prop shop measure the prop.
Its safe to say an 11" pitch will work and be very close to right if it turns out to be off a little
a prop shop can repitch it.