shunter2005

I am currently running a Rev 4 21 on my boat with a 502. I was told before I bought the boat that this particular model requires a little bow lift. Right now, it runs out at 5K to 5.1K rpm. Speedo acting up, so I will take a gps next time out. I would like to try a Rev 4 23 to see if there is any major differences other than lower rpm's. Also, not really sure how going bigger will will affect the hole shot and mid range (my main objective).

My question is this. After reading an old thread here and threads elsewhere, some posters were saying that the Rev 4's were lifting the stern. Now it seems that others here and on other forums say the Rev 4 (stock) is a bow lift prop. I would like to know which is true?

I have always thought that props, like the Bravo 1, are both bow lifting and stern lifting (due to the diffuser ring). The Rev 4, with no diffuser ring would be a bow lift prop. I guess I am now a bit confused by what I have read.

I have both, but I really like the Rev 4 and have yet to try the Bravo 1 on the boat.

phragle

iTrader: (3)

What boat?? a 21 seems small for a 502...

shunter2005

Hallett 270.

I thought so too, but the 21 is what came on it. It does put it in the upper rpm range and that's why I want to try a little bigger prop.

endeavour32

iTrader: (4)

Am I reading this right, your 21p prop is not giving you enough RPM's so you are going to try a bigger prop?

shunter2005

Well, maybe I said that wrong, sorry. Looking to go from a 21p to a 23p. I know I am at the top or just over the rpm range and would like to run somewhere around 4600-4800 or thereabouts if possible.

endeavour32

iTrader: (4)

Going from a 21 to a 23 would lower your RPM's by 400 +/-

shunter2005

Thanks, that's exactly what I think, but I don't want to give up much of the low end or mid range. I do love how quick the boat accelerates and rolls over. My old Checkmate (454mag) took awhile to get up on plane even running a B1 22p.

As stated in my OP, my boat needs some bow lift and running a Rev 4 seems to do that. After reading some old threads here and threads elsewhere, many guys said the Rev 4 gave them some stern lift. If that is true, then I don't want to sink any money in another Rev 4. Other threads say that the Rev 4 (stock) will give the boat some bow lift. I read somewhere, I think on the Mercury site that the Rev 4 is a bow lift prop, but I can't find it again. So, what I really wanted to know is:

Are Rev 4 props (stock) a bow lift or stern lift props or maybe both?

endeavour32

iTrader: (4)

you can always have your prop repitched or have added cup to reduce your RPM. You could have it repitched to a 22. That would knock off 200 RPM's and put you around 48-4900.

Griff

A Rev 4 is not really a bow lifting prop. A Bravo prop gives more bow lift.

Your WOT rpms are near perfect where they are. It is best to run at the upper end of the recommended rpm for peak performance.

ToMorrow44

My experience with the rev4 is it's an all around lifting prop. Seemed to lift the bow and stern on my boat which it didn't like at 80+. but I always kinda thought the rev4 would work well for the 496 and 502 powered boats because it helps free up the hull at more moderate speeds.

As to your question, I'd leave the pitch alone if you're able to spin it to within a few 100 rpm of the rev limiter. The bravo may be a touch faster on the top end but I think the rev4 would probably be your best overall prop. The hydromotive q-iv-x is also a good bow lifting prop if you're looking to play around with props.