The V 20 hits 50mph tops, but any faster ?

[RidgeRunner]

First trip to the water was a success. I had a few problems. Trim pump won't trim the motor under full throttle acceleration. Wires look suspect to me. But it is probably a check valve issue in the pump. Second problem was the paint job on the gearcase. All the paint was stripped off while underway. No signs of primer.
250 EFI motor ran great. The additional weight did not go without notice. I prefer the lighter 200 and the way the boat would sit without the extra weight. The boat will porpoise now with higher trim angles but seems to go away with a little tuck, used the trim tabs for the first time.
The boat planes at 3000 rpm without trim tabs and runs 24 mph, 34mph @ 4000 rpm , 44 mph @ 5000 rpm and I saw a brief max speed of 54.1 mph @ 6100 rpm. Only four hours run time with new rings I didn't want to push my luck.
Boat handled great, no noticable difference on plane and no problems with the extra speed. Obviously not enough prop but I have a good feel for what it is capable of now. 60mph ain't gonna happen.
I was turning a 14.25" x 19 pitch Quicksilver prop.
The bow isn't flying. I am going to try a prop with more cup and rake. Any suggestions?

[THEFERMANATOR]

Originally Posted by RidgeRunner

I am going to try a prop with more cup and rake. Any suggestions?

I would be careful about going that route. More cup and rake will INCREASE your bow lift and make your porposing worse. I would try a 4 blade prop with moderate rake to it as that will help to lift the stern up some and help hold the bow down. Call Ken at PROP GODS and see what he says.

[Genie Aye]

Originally Posted by THEFERMANATOR

I would be careful about going that route. More cup and rake will INCREASE your bow lift and make your porposing worse. I would try a 4 blade prop with moderate rake to it as that will help to lift the stern up some and help hold the bow down. Call Ken at PROP GODS and see what he says.

I am in the same situation with my set up. The evinrude stainless prop has a big cup and rake and gives to much bow lift for my liking. I am going to try a couple 4 blade props to see about picking up some stern lift.

my speeds--Just FYI

4000@37
4500@44
5300@53+

But I am swinging a 15 1/2 X 19 rebel stainless prop.

I will by the hub -prop set up so I can run several different props to see witch 4 blade is going to do what I want.

[RidgeRunner]

Originally Posted by THEFERMANATOR

I would be careful about going that route. More cup and rake will INCREASE your bow lift and make your porposing worse. I would try a 4 blade prop with moderate rake to it as that will help to lift the stern up some and help hold the bow down. Call Ken at PROP GODS and see what he says.

Thanks Ferm I saw the Prop Gods on Google. For $95/hr they come to my lake and the fun begins. Since I am running a few too many rpm now the 4-blade 19 might be perfect. I never had any porpoising at WOT only at lower rpm while cruising with too much positive trim. I was thinking that the bow is riding pretty flat at WOT.
This hull was never intended for this much speed. It isn't scary fast but it really isn't practical either. When I get to go fishing on the weekends, I don't get to choose what the weather is going to be. The extra speed could be used about zero percent of the time on my average outing. I like the 35mph cruise @ 4000 rpm. I understand the 4-blade kicks butt in mid-range and acceleration.

[THEFERMANATOR]

If you go to him he will cut you some slack on prop testing. I would try the boat out in a chop before you make any big changes though. A chop changes the way everything works. I know my engine is mounted too low on the transom for top end, but in a 2-3 chop it is just right as any higher and it would blow out constantly.

[spareparts]

i would try a 21 Mirage plus, its probably one of the best all around props made. It doesn't work well on some of the higher strung 2 strokes, but on your 3.0L it should be fine. One of my friends is running a 19 Mirage on his 20 Grady with a 225 Yamaha 4 stroke, it runs better than all the other props we've tried. Look at the mercury "thunderbolt" its an alternative marketing brand of the Mirage, it doesn't have the deep ingaving on the side, and doesn't have the cavitation holes, but other wise(according to my prop guy), its the same blade design and surface area of the Mirage, and its much cheaper

[THEFERMANATOR]

I'm spinning a 17 pitch APOLLO large diameter which is the generic equivelant of the MIRAGE. It's a pretty good prop that has virtually NO slip to it. I get close to 2-6% prop slip when running it hard which is a pretty solid bite. Also a MIRAGE style blade will take about 2" less pitch than a smaller diamter will. I've hit 53 with mine turning in the 5800 range on my HYDRA with a REALLY light load, but 48-50 is pretty achieveable on a regular basis.

[spareparts]

for a three blade, they are really efficeint, they give a bit better top end than a four blade with allmost the same cruise, hard to beat a four blade for midrange.

[RidgeRunner]

Great info. I definitely need to step up in pitch. It is on the limiter at 6100 rpm. I like the Marage on my Whaler it is highly polished. Do all Mirage propellers have the big diameter? Does polishing help or change anything?

[THEFERMANATOR]

The MIRAGE is a large diameter prop. There are 2 different styles of them though, the new ones with the XHS and the old ones without. The blades were changed some as well with the hub change. When you step up in diamter it will act like you went up in pitch. I went from a 15 pitch 14 5/8 diameter prop that woulkd turn up to around 6400 with a load in the boat to the 17 pitch 15 1/2" diamter that will barely hit 5400 fully loaded(5600-5800 light load). The mirage stylke blade is very efficient so it acts like an inch or 2 of itch just by going to it. I would try a 19 MIRAGE and see what it does, also you need to get somebody to help you check your engine height while running.