I was on the Cleveland poker run last weekend on a 2002 42 Fountain w/ 575's. The boat ran 88 according to the Fountain test, ran 85 on GPS in April upon delivery test run.

During this poker run it would only see a best of 81 on GPS. It is spinning 32 Bravo ones to 5250 with a 1.5 gear.

Mathematically it should be running 106 (using 32 for the prop #) or 101 (using 30.5 as the prop #, which is probably more accurate with the Bravo props) minus slip.

12% slip comes up with the 88 that it did at the Factory.

20% slip is more like where it was at.

it was about 90 degrees out, humidity?

2 other people said they lose 10% with hot weather on the 575's, but 2 other boats w/ 575's there were running right on, what's the deal?

I don't know the answer to your problem, but this is not good unless you had a lot of people and fuel on board.

Year before last I saw 81 MPH on the GPS of a friends 42 Fountain with 500 EFI's. I do not know off hand what props he was running, but they were stock from the factory.

Good luck.

Mark

The boat started out full of fuel and with 4 people, we burned over 120 gallons of Fuel on the way to Cedar point and it didn't even pick up 1 mph.

So we filled it up again and ran wide open the rest of the run (20 minutes to put in bay & over an hour back to Cleveland)
- again no change at all in speed.

They claim it had 100 gallons of fuel and 2 people at the factory test.
It definitely had 100 gallons of fuel and 6 people on the 85 mph delivery run.

Heat and humidity.

For every 10 degree increase in intake charge temp you can expect a 1% decrease in power. GET AN INTERCOOLER, vent the engine area! Get one of those cheap thermometers with a long sensor wire (radio shack) and put the sensor next to the air filter on the engine and seel what that temp is. You'll be surprised.

Both hatches were open about 2-3 inches to let air in-and left that way for an hour while running-no diff

a 10% loss in speed would equate to a 100 degree difference in intake charge temp? Is that possible

Could be bro...the humidity and heat play hell with them. To test in salt then in fresh is gonna change things as well...get the super chillers.

Frank,
Reggie probably tested in the brackish waters of that river in the middle of the winter with his helicopter spotting for ice bergs !!

Hey, that's how he tested mine! (28 degrees the day mine hit the water - and I'm trying to make the test sheet speed on GPS, in Houston?! )

Fountain's test sheet is completed manually. No external gauges or calibrated test boxes. They said my 42 w/500efi's went 83.4 but with my GPS running at the same time as there's read 81.2.

Lake X dialed it in and got 82.3 out of it. I would belive Lake X over Reggies bunch anyday. They said if my my boat had the 575's it would run 85 to 88 tops