I have 2001 Fountain w/ 900 HP Imco 2" shorties. I'm turning 4 blade 33 pitch lab mercs , 6100 rpms. The boat is hard to get on plane and I don't want to turn but 5800. Any suggestions would be great.

I think clarifying your goals will be helpful. I think we should look at propeller efficiency as well.

What is your gear ratio?
WOAT RPM?
WOT MPH via GPS?
Original Pitch stamp on the propellers from Mercury?

Julie

102 mph on GPS, 6000 to 6200 rpms/ tach stops @ 6000
Props are stamped 33, I think they were 32's
I just changed gear ratio from 1:25 to 1:50

Your slip is high. It's not unusual to see these #'s with your set up and gear case adjustment. The planing situation can be attributed to the hp and drive heights.

I'm sure the props were made from 32P castings. The cast in part # for 32's would be 831919 and 831920 (side of the exhaust tube). Mercury would rarely work 34 back wards for various reasons.

Why did you change the gear ratio? Are you looking for more top end or just all around better performance? What way are you turning the propellers

Your existing propellers can be adjusted to control another 300 rpm. Otherwise you will need to change set up or consider 5BL propellers.

Props are turning inward. I did not like the 1:25 gears, it didn't seem to have the " punch " it should have.Plus looking for a little more top end. Would like to get the cruise speed up. I'm thinking 32 five blades maybe five blades will help get on plane.Should have went with 1:36 ratio.

Your 1.5 gr is fine. I like to use the lowest ratio possible for the reason you stated. The down side is they are slightly less strong than the taller gears. But your not too high with pitch and thats good. Spinning in is also good on this application as long as your docking is OK.

If you go to Maximus 5BL props, we would suggest 32P Labbed at 15.25" diameter. They will increase your mid range and planing ability.

Thanks Brett, I going to try some 32 Herings Sat. Hope to get good results before my trip to Jacksonville next week. I'm not sure what Dia. they are, how much difference will it make from 15.25 to 15.50?

The rpm's increase as diameter is reduced. Also, the stern settles more as the diameter is reduced. 1/4" adjustment on a 35 Fountain doesn't have the same impact as a 1/4" on a F1 tunnel boat. It is noticeable though.

Let us know how your testing goes!

Well the stinking 32 - 5 blade Herings would not get on plane.Had to put 33 bravo's back on. Do you think 5 blade hydro's or merc's will work, before I lower the drive 1".

It sounds like you are getting to much stern lift from the Herings. The Round Ear 5B will not produce as much stern lift.

Julie