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

[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.

[RidgeRunner]

Got it. I know it to be risky by myself but the motor height was the first thing I checked. The lighter 200 was perfect mounted in the top hole the cav plate was right on top at 40 mph. The 250 seems to be a little low, I can barely see the top of the plate while underway and I mounted it using the second hole. It has a tiny bit of spray coming off the lower on one side only. 3/4" higher should do it. The bracket was mounted per the directions.
The Mirage 19 will be my next prop to test.
BTW I have been posting for a album. I need to reach 100 posts. LOL
At this rate my album will be here next week.

[RidgeRunner]

Nothing to report. Bronchitis slowing me down. Hope the boat is immune. I've looked into actual hp numbers on the 250 EFI and I think with a little more setup it might reach 58mph.
I have been second guessing the decision for more speed. I think this old girl deserves better treatment than what she is getting right now. You know, run hard and put away wet. I am a gearhead but I don't really have the speed bug. Besides fat people get distorted over 55mph...

[Genie Aye]

Just a question--Is not the 250 over the rating for the boat>>

Mine has a rating of a 235hp.

Just curious if these boats varied on the HP ratings for different years.

[spareparts]

I'd raise teh engine to the top hole and try the 21 Mirage, if you get the engine too high, you will know it, then you won't have to wonder how it will run rasied anotehr hole, its allways easier to drop the engine down a hole than raise it. Liek I said, my friends 20 grady spins a 19, its a heavier boat than a V, plus he has a big T-top with full cnavas. That 225 Yamaha spins teh 19 with no problem. I don't remeber the different gear ratios on teh Yamaha verses your 250 Merc (1.75 i think), but I'd guess you should be able to spin a 21.

[THEFERMANATOR]

Originally Posted by spareparts

I'd raise teh engine to the top hole and try the 21 Mirage, if you get the engine too high, you will know it, then you won't have to wonder how it will run rasied anotehr hole, its allways easier to drop the engine down a hole than raise it. Liek I said, my friends 20 grady spins a 19, its a heavier boat than a V, plus he has a big T-top with full cnavas. That 225 Yamaha spins teh 19 with no problem. I don't remeber the different gear ratios on teh Yamaha verses your 250 Merc (1.75 i think), but I'd guess you should be able to spin a 21.

I know a friend of mine has a 21 KEY WEST with a 225 YAMAHA 4 stroke and he spins a 19 pitch STILLETTO to about the same RPM's that my 225 EVINRUDE spun a 15 STILLETTO, he maxed at 6100 running 52 and I maxed at 6400 running about 50-51. Those 4 strokes have a pretty deep gear ratio to them in the lower unit.

[RidgeRunner]

Originally Posted by THEFERMANATOR

I know a friend of mine has a 21 KEY WEST with a 225 YAMAHA 4 stroke and he spins a 19 pitch STILLETTO to about the same RPM's that my 225 EVINRUDE spun a 15 STILLETTO, he maxed at 6100 running 52 and I maxed at 6400 running about 50-51. Those 4 strokes have a pretty deep gear ratio to them in the lower unit.

Ok, local marinas looking to see what they have for props. One said YES over the phone to several 21p test props and when I showed up in person you would have thought I was speaking Russian, Nyet!!.
Raising the motor to the highest position on the bracket, Friday. That idea is genious. Tweaking on the throttle plates to adjust idle down a bit.
My motor guru claimed mid-50's. He stated that I would be fighting the wind with my t-top and console as it is currently set up.
Since I have totally hijacked this thread I would offer that a light 20 with the proper setup and 250hp would be able to achieve 60mph without question. It would be cool to start with a CC and install a small console all the way to the step for the casting platform.
Bare essentials with a bucket seat that just offers a view over the bow.
Or maybe a cuddy with a small windscreen. 60 would probably arrive with less than 250 hp if the hull was light enough.

[RidgeRunner]

The hp rating on the boat in 1983 was 200 or 235. I know the early 20's were rated much lower. Going back to 1970 for instance there was no such thing as a 200 hp outboard. The max rating was 135 in that year. Several factors have led to the change in hp rating over the years. At some point I belive they changed due to Wellcrafts decision to go with the OMC SEADRIVES.
You raise a good point and in doing so opened the preverbial can of worms. What is the law? My 20 has no plackard for hp max persons etc.
I really don't have plans to run this package for long but say I get pulled by a wildlife officer, what would happen?
There is a really cool website for fast boats called SCREAMANDFLY.com, It is absolutely insane what motor and boat combinations you will see there. I don't think it really matters what you put on the back of the boat until it is
1. Time to ante up for insurance or
2. When you are sitting in court trying to defend your bacon after something went terribly wrong.

[Steplift 72']

Originally Posted by RidgeRunner

The hp rating on the boat in 1983 was 200 or 235. I know the early 20's were rated much lower. Going back to 1970 for instance there was no such thing as a 200 hp outboard. The max rating was 135 in that year. Several factors have led to the change in hp rating over the years. At some point I belive they changed due to Wellcrafts decision to go with the OMC SEADRIVES.
You raise a good point and in doing so opened the preverbial can of worms. What is the law? My 20 has no plackard for hp max persons etc.
I really don't have plans to run this package for long but say I get pulled by a wildlife officer, what would happen?
There is a really cool website for fast boats called SCREAMANDFLY.com, It is absolutely insane what motor and boat combinations you will see there. I don't think it really matters what you put on the back of the boat until it is
1. Time to ante up for insurance or
2. When you are sitting in court trying to defend your bacon after something went terribly wrong.

I haven't seen the rating on a 70 model, my 1972 was rated for twin 115's on the transom info plate.

[reelapeelin]

Way to GO, Ridge!!...seein' that number go past 60 musta been worth every $$!!...

I like the way your CC sits...some we have seen here sit butt-heavy w/a bracket and big HP motor...NICE!!

Do you have trim tabs?...might pick up a couple more MPH and keep the bow-fly down better...who knows??...