3000 SCR performance

[pgp]

Hiya,

I have twin 4.3s and bravo drives. Not sure what the props are. They are 3 blade aluminum. At WOT I get 3800 RPM giving a top speed of about 28 MPH. It jumps out of the hole with no problems at all.

Yes the bottom is clean as are the props and drives. No it doesn't make much difference if the tabs are up or down. Yes the fuel is fresh. The engines rev freely to about 5000 when not under load.

Does anyone have any ideas on prop specs? Do any other 3000 SCR owners have any speed / performance figures?

My reason for asking is I would like to get the correct props so that I can maybe do 25 MPH at around 3200 - 3400 RPM or lower. I am happy to sacrifice hole shot over economy.

[mmwjr]

So what Bravo drives do you have BI, BII, or BIII?

[pgp]

Hi Mike,

I think they are BII but not really sure. The online look up is very ambiguous.

These are the serial numbers and props....

Port Engine: 0L047632 Stbd Engine: 0L047633
Port Drive: 0L176209 Stbd Drive: 0L176208

Props: RH: Stbd QA1940R (48-18614A40)
LH: Port QA1941R (48-18615A40)

[mmwjr]

Ok the prop numbers you gave say it is a BII and the props are 18 1/4 X 19, the first number is the diameter and the second is the pitch.

Dropping to a 18 1/4 X 17 will increase WOT by about 200 rpms.

You may want to contact Hill Marine or use the Mercruiser prop calculator for recommendations.

[pgp]

Thanks for the info Mike. I will start the research and see what happens

Book says RPM range is 4400 - 4800.

[Phillbo]

Call Hill Marine. They will dial you in. Your WOT sounds a little low.

http://hillmarine.com/?gclid=CK3f5crDtsECFQiIaQodxBAAhA

[shrew]

Originally Posted by pgp

At WOT I get 3800 RPM giving a top speed of about 28 MPH. I would like to get the correct props so that I can maybe do 25 MPH at around 3200 - 3400 RPM or lower.

That is an unrealistic goal.

https://www.mercurymarine.com/en/us/...tor/#/step-one

[pgp]

[QUOTE=shrew;35034]That is an unrealistic goal.

My neighbor has a searay 29 with twin v6 and gets 25mph at 3200 rpm. His boat is about the same weight as mine, so should be doable....

[mmwjr]

Does he have BII's as well?

[pgp]

Not sure if they are BII or Alphas, but they are NOT duo-props..