larger diameter okay?

was wondering aabout trying a 16" diameter prop on my mercruiser. 1850 tyee, 4.3lx. no real reason, just that i've been playing around and all my props ive tried are 14-143/4". noticed suzuki props are 1`6" and have access to some. was told the splines will match. anybody know if they do? also what gain/losss should i see from the larger diameter?
thanks.

Re: larger diameter okay?

The info you gave on what you have and what Suzuki your talking about is pretty skimpy.
Using Hustler props for reference it does appear that the 4.3 and the Suzuki 150 2 stroke use different hubs.
And the 150 Suzuki 4 stroke doesn't list a Hustler application.
That could just be the iboats inventory.
A very brief look at props it seemed that the 16" diameter were around a 14" pitch.
All that said speaking very generally assuming the same pitch a 16" diameter would be harder to turn and would tend to lower rpm.
larger diameter might resist venting better.Larger diameter might work better on a setup the has a relatively low rpm.

Re: larger diameter okay?

It isn't just about the splines matching. Hub depth (front to back) and hub diameter are also factors. A hub whose diameter is too big will not fit the lower unit. One that is too small may allow exhaust to bypass around the hub and create ventilation. Unless these props are dirt cheap, I would stick with what you have especially since there doesn't appear to be a performance issue. If your engine spins up to the upper end of the manufacturers recommended rpm band at wide open throttle with an average load, you have the correct prop. Any improvement from that would be marginal or you would give up one factor for another. Hole shot for speed for example or vice versa.

Re: larger diameter okay?

brunolund said:

was wondering aabout trying a 16" diameter prop on my mercruiser. 1850 tyee, 4.3lx. no real reason, just that i've been playing around and all my props ive tried are 14-143/4". noticed suzuki props are 1`6" and have access to some. was told the splines will match. anybody know if they do? also what gain/losss should i see from the larger diameter?
thanks.

Click to expand...

Based on the info you have given I would not recommend doing this. Even if you did find a 16'' diameter prop that would fit your drive(most likely a 4 3/4 gear case), I'm betting that you are going to see way too little RPMs. Pitch of a prop is the # that makes the biggest difference. Don't get me wrong....diameter matters too but not as much as pitch. You can also try props with different rake and cupping as well. There is also the fact that pitch vs diameter vs rake has a huge affect on weather or not the prop will hit your cavitation plate as well.

Re: larger diameter okay?

brunolund said:

was wondering aabout trying a 16" diameter prop on my mercruiser. 1850 tyee, 4.3lx. no real reason, just that i've been playing around and all my props ive tried are 14-143/4". noticed suzuki props are 1`6" and have access to some. was told the splines will match. anybody know if they do? also what gain/losss should i see from the larger diameter?
thanks.

Click to expand...

The general rule of thumbs is decrease of ~400rpm per additional inch of diameter - pitch remaining the same.

Based on the diameters that you've indicated, 500-700rpm loss - again - pitch remaining same. If the pitch isn't adjusted accordingly, you'll actually lose more rpm, since the motor will fall out of it's rated horsepower powerband.

As you can see, you'd need to drop pitch considerably to keep the engine in it's power band. The rule of thumb - which I'm sure you've heard...1" pitch ~150/200rpm change.

If the goal is to turn that lund into a stump puller, you're moving in the right direction.

I can't speak to the Suzuki prop fitment. I'd have to have the Suzuki prop in hand to see if it can be shoe-horned on adequately to make a test run.