06’ 198 with 225 SHO - 4-1/2” prop below pad- good?

[Sluggo42]

Hi guys,
I just measured and my prop shaft I’d 4-1/4” below pad-
anyone know if this sounds like a good starting point? I was thinking of moving it up to 3-1/2” to start.

[Bass in the grass]

Mines about 4”, but I have a merc and a tempest. You can always experiment, just make a mark on your plate to go back to, in case you make it worse. Don’t always believe the “it has to be ***” crowd, all boats react and run differently.


and I believe you’re running lithiums, you might need to drop it. Probably would help to post your RPM’s, prop pitch and speed at WOT.

[Sluggo42]

Going tomorrow to test
previous top speed was about 62, I think the rpm’s were 5300, and prop is a mercury FURY 25P 3 blade

[Bass in the grass]

You’ll probably need a 24” pitch. The 25 is a bit much for these heavy slugs.

[SCOTT196]

Probably need to be a lot higher with motor.

[Sluggo42]

I cranked it up to 3.5” we’ll see what kind of numbers I get

[bassfisher444]

Need to flash it to a 300 as well.

[Sluggo42]

lol- flash it!

[bassfisher444]

lol- flash it!

Yes, Hydro Tech Marine does this.

[Sluggo42]

Ok- definitely an improvement!
hole shot is night and day better- I mean it just leaps-
got to 68 mph, at 5450 rpm, and over 20 psi water pump-
probably good enuff for me now,
until I flash it of course…

[SJSharky00]

Congrats!!
Now go fish!

[ThomasD]

Ok- definitely an improvement!
hole shot is night and day better- I mean it just leaps-
got to 68 mph, at 5450 rpm, and over 20 psi water pump-
probably good enuff for me now,
until I flash it of course…

Still about 700 rpms shy of what it should be turning

[SCOTT196]

Hell yeah!

[SCOTT196]

How high did you raise it? Did you try it higher?

[Sluggo42]

How high did you raise it? Did you try it higher?

I raised it 1”, to 3.5”. I might go another 1/2” and see what happens- I also might change out the prop, from the Fury, to a worked Tempest 25, that came with the boat…

[Tx Champ]

That SHO has more balls than a Merc 4S. I bet it'll do good with that 25.

[SCOTT196]

You probably need to be higher. If
So you will pickup more speed and lift , watch water pressure !

[Ed R]

3.5" PTP is pretty high on a 198 with a 3blade prop. From where you are, I'd go up 1/4" at a time until you gain rpm and lose speed. From there, drop it back down to last setting, your good for that prop. Also keep an eye on water pressure.

[Sluggo42]

3.5" PTP is pretty high on a 198 with a 3blade prop. From where you are, I'd go up 1/4" at a time until you gain rpm and lose speed. From there, drop it back down to last setting, your good for that prop. Also keep an eye on water pressure.

great guess! I did go up 1/4” and lost 1mph, and it felt squirrelly, so dropping it back down to 3.5.
next move is to put the Worked Tempest 25, on and see what happens with that one.