can i get more from it??

[fishfeatures]

hi,

I have a johnson 60 hp with a 13.25 x 17 aluminum prop. It's on a Fletcher 14 ft (ski boat) and at WOT 5500 it'll do 34 mph (gps). Usual load is two adults 50 litres fuel, anchor, battery, extra clothing and grub.. and that's about it.

My query is this,

At WOT I feel that I can get more from the engine as the last 5% of WOT doesn't increase performance but it seems like i have gotten the max from the prop. Can i step it up to say 13 x 19 or so ? will that use the rest of the power my engine seems to want to give me? Would moving to a stainless help me ??

My hole shot is great so I don't mind sacrificing some of this to acheive a better overall result. Now when i say result I mean that i just want the motor propped so that all of it is used I don't want 6 hp or so just sitting there not able to do any thing if you know what i mean.

 

[steelespike]

Re: can i get more from it??

Is the 34 with just you?seems like you could be closer to 40 mph
You might be able to raise the motor on the transom.The antivent plate (just above the prop)
should be about even with the bottom and could be up to an inch higher.
Is the prop in excellent shape? Do you trim carefully?Does the boat respond to up trim?
Is the carb(s) opening all the way?Motor in excellent tune.

 

[fishfeatures]

Re: can i get more from it??

34 is with 2 36 with one. I do think that the motor is lower than the transom but becuae it is bolted to it I don't wan to move it as i wwould need to redrill and that ain't a preferred option yet...
Prop is without a nick in it and my lil baby responds well to trim and I'm pretty ok with how I have her trimmed. motor totally over hauled as it was seized so everything motor wise is spot on inc carbs full lync and sync done and timing checked etc..
It's just when she is pushed full out the engine has that little bit more to give,, but I just don't get the bit more speed from her, and I'm thinking bigger pitch will use the few rpms left and drive me on that bit more..

 

[Texasmark]

Re: can i get more from it??

Is the 34 with just you?seems like you could be closer to 40 mph
You might be able to raise the motor on the transom.The antivent plate (just above the prop)
should be about even with the bottom and could be up to an inch higher.
Is the prop in excellent shape? Do you trim carefully?Does the boat respond to up trim?
Is the carb(s) opening all the way?Motor in excellent tune.

I had a 15' Kingfisher bass boat with a 70 Rude once. Kingfisher boats are somewhat narrow for their length and the bottom is flat for the most part then make a quick rise at the bow for water entry.

I didn't have a tack and I don't remember the speedometer numbers, but I had pretty good performance from the boat. I remember jacking the engine up only one notch...slid a piece of 1x2 redwood between the engine clamp and the transom top before bolting down as I recall, and the difference in performance was stellar. As a result, I upped the pitch on my prop, don't remember the numbers, but it took it and took off.

With that said, if you jack her up, with your comment about where you are currently with your hole shot, I wouldn't be surprised if you could go up 2" in pitch and maybe more and be just thrilled....on SS props, unless you have a high performance alum, like A Turning Point Hustler, you definitely will get better performance from a SS prop. As I recall I had an alum prop on a 125 Johnson on an 18' boat and replaced it with their newly released SST of the same pitch (but it was cupped). Difference was definitely obvious...don't remember the numbers....was 1972. Just changing to SS will give you cupping which is said to be equivalent to 2" of pitch increase, especially at the top end, and with your engine higher in the water, you will appreciate the cupping's ability to keep your prop locked in on tight turns and not breaking loose (ventilating and loosing speed with a sharp increase in rpm's).

Oh and my current boat...the one in my Avitar, is a palsy 90 Merc on a 17' BB and I have GPS'd it at just over 50 with a 24P Ballistic SS prop. The wake it produces is just what you see in the pic....that's it; speaks for it'self. The engine is raised 1 notch above the normal transom height setting (3/4)".

Nuf said. Good luck.

Mark