zx14

just got back from the lake. I borrowed my buddies 28p labbed bravo. I was on the rev limiter at 5600 rpm and doing 101 on GPS. and no soot on the transom. Pulled like a angrey ape from 60 to 100. It was cool out maybe 65-70 degrees. So I would say the 32p is too much prop for havasu heat. I am guessing a 30p may be just right? Can a 32p be worked to a 30p? I did notice I am popping up through the top on occation, "to much advance" can it be set in the traditional way or is it all in the ecu?

DonRoc

You can lab a 32. Which is what I would do. Get all the numbers from it, RPM, Speed and call Brett @ BBlades

DonRoc

We need to start from scratch. You wrote you pulled 5800 with a 32 @ 98mph , now only 5600 with a 28 @ 101mph??? And the numbers with the 28 do not work unless you have a 1.35 gear. Run it again with the 34.

If you are popping thru the intake on occasion I would think its lean and the program needs to be tweaked.. You really need to set it up with an O2 sensor and Data log it. Then find someone who can adjust the program. Is it a Mefi (merc)system? Or aftermarket?

zx14

ok, ok I was wrong on my first post. I meant to say 4800 when I said 5800.
The ignition is a MSD box and distributor, but it also has the merc ECU. It was tweeked by az. speed and marine. I talked to them yesterday and they did say they set rev limit at 5600. so that makes sence. the boat with the 32p in the heat would only pull to about 4800 revs and the transom turned black. so running the 28 let it rev and eat that fuel." i am assuming"

And yes I would assume its a 1.36:1 gearset, by using the prop calculator.I cant get a wrench on the front of the motor to turn it" The docks where a zoo today so changing props was not gonna happen, I am going to go back next weekend early and hopfully have the cool air again and see what it does. I feel like I need to roll the timing back a bit. Or it may be like you said and have a lean spot. The plugs look good.

it is a labbed 32 by BB Blads.

I bought the boat with not much info other than what I was told, took it for a long test drive and it seemed real strong and didnt blow up. Reserched the dealer and Bob at eliminator said he was a strait shooter, so, I rolled the dice. Not ez these days to finance a cat without a dealer.

DonRoc

That makes since. The 32 labbed should have turned more. my guess is the 28 is just at the limit. That would put a 30 @ 5200-5300. and the labbed 32 should be near 5100 or so . Unless it was labbed to pull down the RPM's not increase them. But some good numbers with the 32 and Brett will get you where you need to be. You should check the base timing but popping thru the intake will not be fixed with timing.

DonRoc

Sorry I did the numbers on a stock 28. You still need to get some numbers on the 34 but may need a labbed 30. Talk to Brett

zx14

Thanks for the input Don, next saturday with my 32 , hopfully cool morning air and I will see where its at. I am guessin a 30p may be the ticket for all around. Be nice if the 32p could be worked down to a 30p. The boat came from Wisconsin, I am guessing they dont see many 110-115 degree days on the lake. So the labbed 32p may be great for that area.

skydog

Well so far guys with my 27' I went 115MPH with four peope right to the rev limit of 6gs with a 32" Bravo one Put a 34" Bravo one on and went 120MPH with one on bourd to the rev limit of 6gs looks like i need a 36" prop.

Skydog