1.87:1 versus 2:1 gearcase

[Jgebhardt]

This will probably seem like a silly question but I am new to speed boating and I am not sure what the answer is.

I have Hydrostream Valero YT with a 225 Promax on it. It runs 92.2 mph with a 2:1 gearcase and a 32p cleaver turning 6500 RPM's. I am considering going to a 1.87:1 gearcase. My question, would I gain more speed with the 1.87 using the same prop?

I know this is a rookie question but I am not sure. Never really messed with outboards before.

Thanks in advance for the advice.

[FORBESAUTO]

Probably not, you will loose roughly 400 rpm and speed should be roughly the same. May actually loose due to less power at the lower rpm. Now a prop change to lower pitch could possibly help. My experience is mainly just moved rpm around. A lot depends on what rpm engine makes most power. Pro max should like the higher rpm.

[texasvector]

1. how heavy is your valero??? where is prop shaft height?

2. the p max makes good power around 6500-6800 rpm....i wouldnt think you would loose that many rpm ......but only one way to find out

[Jgebhardt]

According to the Hydrostream forum it weighs about 675 without the motor. I am turning a 32 cleaver 6500 rpms and that's all it's got set up the way it is. I'm about 3/4" below the pad. If a had 1.87 laying around, I would just try it and see but I don't want to spend the money and be slower.

[Jgebhardt]

It runs at 6500 rpm's right now. If I put something like a 30 on it I would have to turn about 500 more rpm's just to get the same speed. I'm kinda thinking 92.2 mph might be about all this boat has in it without getting into the motor.

[transomstand]

According to the Hydrostream forum it weighs about 675 without the motor. I would just try it and see but I don't want to spend the money

675 when built, it could be 950 today if water logged.

And if you don't LOVE throwing away money, you're in the wrong sport:D

That boat/engine package should run 95+

[Jgebhardt]

675 when built, it could be 950 today if water logged.

And if you don't LOVE throwing away money, you're in the wrong sport:D

That boat/engine package should run 95+


It it is definitely not waterlogged. I have been all over the boat and also cut two holes in the floor so I could get a look underneath the floor. The boat is ROCK solid. It belonged to an older guy before me and up until I got it the boat hadn't seen the water since 07 when his wife took it in a divorce then she just left it sit in the garage until she wanted to rent out the house that she also took from him in the divorce.

Im not really in it for the sport or racing. I just want to go as fast as I can get it to go, whatever that is. If a 1.87:1 won't make much difference then I suppose I'll probably just leave it alone. It's not that far off from 95 now. I just thought maybe I could find a few more tweaks to get a little more out of it.

[FORBESAUTO]

I would play with props and set up.

[David]

If it were mine I would raise the engine, hook up the kill switch and put on my lifeline...

[Jgebhardt]

If it were mine I would raise the engine, hook up the kill switch and put on my lifeline...


Raise it it how much?

[FORBESAUTO]

1/4 inch at a time while monitoring speed and water pressure. Should take less trim to reach max speed as you raise.

[texasvector]

im not valero expert..but id do like they said.....raise motor 1/4" at a time ....youll gain rpms...maybe speed

[texasvector]

and ill add.....i think the promax with 2:1 combo is a bad pair especially with a stock box for trying top end stuff....i ran that setup before....pulled great with a 30 but no bueno for much over low 90s

[Jgebhardt]

and ill add.....i think the promax with 2:1 combo is a bad pair especially with a stock box for trying top end stuff....i ran that setup before....pulled great with a 30 but no bueno for much over low 90s

That's what I'm trying to find out. Would a 1.87 do better got this?

i forgot to mention in my post that I'm running 6" of setback.

[W2F a V-King]

Is the ECU holding you back, or are you out of motor at that 6500?
Isn't the rpm limiter on a PM 225 kicking in about that RPM? The ECU starts adding fuel to keep the RPM's down?

Either way, on a small light boat with a lot of power, the 1:87 would be my choice of the two ratios... Then prop up or down accordingly.
They come stock with the 1:87.

[phillnjack]

what exactly is the speed your after ?

[FORBESAUTO]

Agree 1.87 gear is better choice for boat/ motor combo. But if he is not on rev limiter and keep same prop I'm afaraid his speed won't change just turn less rpm. Now 1.87 gear and prop change may be an improvement but costly. That's why I suggest play with props and set up instead. Most props can be tried on a loaner program. If it doesn't work your not out much. Change gears and your out. I feel you can run just as fast with 2.0 with enough pitch and bite for less$$

[Snotrekie]

torgue is ET and RPM is MPH. That being said it's easier to set up on the 2:1 gear ratio but more gains can be made with 1.87.

[Jgebhardt]

Is the ECU holding you back, or are you out of motor at that 6500?
Isn't the rpm limiter on a PM 225 kicking in about that RPM? The ECU starts adding fuel to keep the RPM's down?

Either way, on a small light boat with a lot of power, the 1:87 would be my choice of the two ratios... Then prop up or down accordingly.
They come stock with the 1:87.


I think the stock rev limiter is 6800. I've run it in the he 80's with a 26p prop about 1-1/2 to 2" below the pad. My tack wasn't working at the time but if you figure it at the slip I am running now (6.3%) then I believe my rpms were close to 7100. Can't say for sure though. I bought the motor without a power and a 2:1 was what I had laying around. I may just be out of motor, it gets to around 6500 rpm's and that's it.

[David]

You are further below the pad than normal for a light 90 mph boat. It would be much less expensive to play with engine height and props than to change gears.

[Jgebhardt]

what exactly is the speed your after ?

Whatever I can get without getting into my motor.

[Jgebhardt]

You are further below the pad than normal for a light 90 mph boat. It would be much less expensive to play with engine height and props than to change gears.


I've raised the motor up since then and replaced my tach. I'm about 3/4" below the pad now. That's where it runs 92mph with a 32p cleaver. I have been out of town for two months and haven't had a chance to play with my set up any more yet. I'm just trying to get some direction because this is all pretty new to me.

[FORBESAUTO]

3/4 below pad is pretty low for light boat especially with a cleaver. Also I would think an et style prop would be faster?

[Jgebhardt]

3/4 below pad is pretty low for light boat especially with a cleaver. Also I would think an et style prop would be faster?

I am going to raise the motor some and I have a buddy with a 32 et I'm going to try next weekend.

[W2F a V-King]

Sounds like your just about there with what you have now. And getting a second LU with a cone and LWPU is no cheap option. But it might be cheaper than going into the motor, depending on what you do.

You could always get a set of 1.87 gears and put them in the LU you have.

Just my opinion, but the 1.87 ratio is better for you for the top end pull.

[RIVERRUMMER 70]

I assume u have a sportmaster case? if so ......get the propshaft even with the bottom and put on the 32"et....take all the junk out the boat and run her down to 5gal fuel or less and go fast.;)
should do 95.

[Jgebhardt]

I assume u have a sportmaster case? if so ......get the propshaft even with the bottom and put on the 32"et....take all the junk out the boat and run her down to 5gal fuel or less and go fast.;)
should do 95.

No it's not a sportmaster. It's just a standard 2:1 with a Bob's nose cone.

[90 5.0]

On your boat a 200 case with a cone should be faster on top end than a sports master anyway. It has to punch a smaller hole through the water.