sleeper_dave

27' Fountain Fever, single 502, 1.36 drive ratio

With a 19" 3-blad Powertech prop (came on boat), the boat did 60 ish at about 5200 RPM

With a 23" Mirage Plus (borrowed), the boat went faster, 61-62 mph, at 4200-4400 RPM (not all that much testing time with this prop, boat barely got on plane with passengers)

So i bought a used 21" Mirage Plus. I only had it out with this prop once, RPM's were in the 4500-4600 RPM range at WOT but i could't get a good top speed, full fuel, rough water, two passengers. The boat got on plane okay but not great.

I read the thread on the revolution 4 prop with interest. My goals are a good cruise, 3500 or so RPM going 40+ MPH (boat rides better over 40). I also want to be able to get on plane easily with a full load of people. I would like to at least maintain my top speed, at least 60 mph, would really like to see 65. But the planing and mid-range are more important to me. And I like to run the boat hard more than i probably should, so I would like to prop the boat so it only spins 4600-4800 at WOT. I think spinning a BBC over 5000 RPM is just more wear than i need.

So, should i go with a 19" Revolution 4 or a 21"? I'm leaning toward the 21" myself, i don't think the 19" will support the top speed. I should probably be right at 20" but they don't seem to make that prop in that pitch.

BajaRunner

Have you tried a bravo 1 4 blade? It will get you out of the hole easier. The only problem is the smallest one is a 22p. I dont know it they could re-pitch it to a 21 and lab it. thats one route.

you would have an easier time with a 1.5 ratio outdrive.

crb76

Talk to Bblades when he gets back from vacation next week. While at mercury he worked on the REV 4 program. He suggested them to me and I picked up 3mph at cruise and 4mph at top. He just sent me them labbed and I am trying them tomorrow. He can tell you what you need if you even need anything.

throttleup

The 1.36 gear ratio is keeping you in the smaller pitch props. The 27 Fountain typically runs very well with Hydro QIV propellers. But the issue is that you need smaller pitch props so it reduces your selection of high performance props. The stock 502 needs to run at 5000 RPM at WOT to achieve max top end. I would recommend a Power Tech SFS for you boat. It is basicall a baby Bravo I made by Power Tech. It is available from a 15P to a 23P.

Julie

bbladesprops

I'm checking emails and stuff today. Just can't take all those days off without checking in.

dave,

Call us next week and we'll set you up with a 21 Rev 4 to try. With the info you gain, we can decide to Lab it or go to the 19 pitch.

Have a great Thanksgiving.