225pm to 250xs to 300xs?

[90VIPER]

I've recently pulled my 225pm off my concord mach II and bolted on a 250xs and gained a solid 10mph. I've tried countless props, coned and standard lowers and even tried 2:1 gears and larger props on the promax and could never really make any significant gains. My question is...is the 30-35 hp really where the gains come from or is it the torque to spin the big wheel? The 225 was spinning a 23 tempest for a best of 67-68mph....throw the 250 on with a crappy 27 tempest plus and run 77-78 first time out. Also, would similar gains be had going to a 300xs?

[CUDA]

The older 250xs 140 cold cranking compression was really making 270 something, not sure what you have.

[Tango]

My 2003 Alodine 250XS makes 15-20 psi greater cranking compression than my 2012 250XS.

[xb03fs]

Hard to say. My xb21 only gained 9 mph going from 2.5 200/svs to 250 xs.

getting ready to add dbr curve which is supposed to make the 250 more snappy like a 2.5

[90VIPER]

My 250xs is a 2004 and it pulls like a freight train right to the 5850 limiter...i know the 225pm is healthy because it runs right with my buddys jsre 225 and we have the same boat. With some setup i bet theres 3-5 more mph to had with the 250xs. I've heard the 225pm is more like 240-242 hp and the 250xs is 270+. Just surprised how much faster it went.

[CUDA]

Simon reflashes also.

[CUDA]

My 250xs is a 2004 and it pulls like a freight train right to the 5850 limiter...i know the 225pm is healthy because it runs right with my buddys jsre 225 and we have the same boat. With some setup i bet theres 3-5 more mph to had with the 250xs. I've heard the 225pm is more like 240-242 hp and the 250xs is 270+. Just surprised how much faster it went.

That's because you have the older higher compression motor which has 20 some more HP then the newer ones , but you have to run higher octane fuel.

[90VIPER]

That's because you have the older higher compression motor which has 20 some more HP then the newer ones , but you have to run higher octane fuel.

Hmmm...never thought compression made much difference on the top but this thing is an animal...in your opinion what would i gain going to the 300xs? Would it spin a 27 to the same rpm with the 1.62 gear? Always run premium fuel in my boats so that isn't a concern for me.

[CUDA]

Just get it flashed, after that a stroker crank with a little exhaust port work will give you a 300++

I bought three 2004 250XS motors for $11,000 One is becoming a 15" for my lake boat the other or others on

a 26ft Sleekcraft which I put a pad on.

[xb03fs]

15” would be cool. I am assuming it is a costly conversion

[bullwhipjkg]

I did the same thing on a v21 triad went from a 15" 225 promax would run 91-92
to a 2012 250 pro xs went a best of 95-96 with no setup or real prop testing difference in torque was highly noticable

now have a 15" 300 xss conversion going on 2017 motor with dbr flash and added dbr tuner we shall see

promax 26-28 pitch prop
250 30 pitch
300 ???? have acouple 30's and picked up a 32

if I can find a way to get pic off cell ill load it

[CUDA]

www.Madefi.com Todd D is the owner and is the tech inspector for that outboard twin-engine class, SUPER nice guy.

[CUDA]

https://madefi.com/shop?olsFocus=fal...2-08caccc8b2d4

[bullwhipjkg]

acouple of pics

[V-bottom]

acouple of pics

You should be running 105+ with that setup