Sportmaster mods??

[Bullet]

Are there any sportmaster mods that really work? One that will see an actual increase on the top end.. If so, who's the best to send mine to.

Winter will be here shortly you know!!

[W. Tripp]

Modified gearcases will give different speeds with changes in power, weight, and hull design. But this is what I have found while playing around with my STV with a modified Drag engine - take it how you will.

I have modified a Sportmaster much like what is shown on the Baker's "scaryfast" web site. With blunted leading edge, thinned and recontoured skeg/torque tab, filled one water pick up, radiused water inlets, etc. and saw only 1.5 mph gain on GPS at the top end. And the gearcase STILL has a lot of tail lift. I loaned this case to a friend with a Bullet and he liked it enough to buy it.

A 200 style gearcase with a JC's/J&J nosecone and torque tab is worth almost 2 mph more, with less time involved in the modification. It also drives MUCH better without the tail lift of the Sportmaster.

The best gearcase I have tested yet is the Highly modified XR with the larger gears and bearing carrier. This with a JC's type nosecone and torque tab is the best driving gearcase short of a Speedmaster. It allowed me to turn even more rpm and get a few more mph. But the thin skeg is a worry for lake riding - although mine shows no problems on my STV after a couple of seasons of use and abuse. The cost for one of these units is high.

For the money, and for general high performance use, I would go the 200 case and send it to Tooter at J&J Marine (256)729-8095 or 729-0000 for a nosecone and torque tab. Fill it with a good synthetic gearlube (I like Alisyn), and replace it regularly.

If you want to stay with the Sportmaster, do the work yourself. Go to http://www.scaryfast.com and follow the work done there (in the tips section). I would also fill the left water inlet and radius the 2 remaining inlets. If you really want to get carried away, cut the skeg so that it is only 1/4 in. longer than your biggest prop and lay the leading edge angle back 15 degrees more - starting 3 inches below the top of the skeg. Most of the work can be accomplished with belt and rotary sanders (and plenty of sand paper)- it is nothing magical, it just takes time. Send an e-mail to Rob "Firewalker" Twibble or myself for more info. I believe Rob is the one that gave Baker the idea after he showed up at Firewater.

Do not bother polishing the case unless you wish to re-polish it every few times you use the boat. A good spray down with Westley's Bleche-Wite will give the case a dull finish and will keep it looking new.

I hope this helps.

[Edited by W. Tripp on 09-02-2001 at 10:33 AM]

[Bullet]

Wayne,

First time I ordered the 280, I was gonna swap the S Master for a T Master and have JC's do the "magic".. The dealer had my money but kept draggin his butt with the delivery. Sorta felt he was putting me off and takin care of his buddies..

Ordered it from a different dealer and got the Sportmaster.. (we got a short season up here!)

I figured tweakin this Sportmaster is something I could have done over the winter.

Vinnie

[fasterthanyou]

IF you already have a sportmaster its a great lower unit with a few mods. I have all the mods you read above plus i put a radiuos on the rear part of skeg opposite side from the torque tab. Water will follow a curve edge and you can pull it into the bite of the prop.

[Firestarter]

I really have not found that you can make the sportmaster a great case, only liveable. It is a great case in respect to the fact that it is reliable, I does not work to bad, I have a friend flirting with 130mph with one and is working well.
The mods that Wayne has mentionoed above, are what I had run for over 2 years, and they did add speed to the boat, but really never changed the way it handled (kinda ****ty). The only thing that I would add it that I ground the lower half of the blowout ring off to smooth the case a little more, and corked the finish on the case. We have had no failures with this mod, on tunnel boats. 1 on an allison.
Shoot me an e-mail, I can try and explain a little more if that is required

RT

[fasterthanyou]

I thought that the blow out ring helped collapse the water toward the propeller, have you noticed a percievable difference with smoothing the blowout ring on the bottom of the case.
Also what kind of handling problems are you having out of curiousity and what hull do you have. I have a mirage and the sportmaster handles the same if not better than my modified 200 case, not that I am the authority on this subject just curious on other hulls. I also have hydraulic steering which may makes makes driving the boat very easy.

[Firestarter]

I know very little of the Mirages, but I can say that they need all the stearn lift they can get to work well. The sprtmaster has this. I have a lot of experiance with the STV's and am learning on the Allisoonies.
Handling is mainly in the slowing down of the boat, it is hard to get it to settle nice. STV's have a very sharp set of sponsons that can get darty if you try and slow them down from the super high speeds.
Mirages blow over, STV's hook.-----both are preventable with proper set up.

RT

[fasterthanyou]

My rig has always run best with little trim and very flat, I think you have to really be set up wrong or have tipped way to many beers to blow one over. I know what you mean about the stv i have a buddy who has one and it definately take more driver input

[Firestarter]

Don't let the fact that you run your motor flat or even negative lure you into a false sence of security, the Mirage WILL blow over. I have seen it too many times, had their have been a lot of deaths. Though you are correct that they are easier to drive, and setup helps. They are great boats, but like all designs, they have their idiosyncracies.
But a properly set up STV has no ill- manors till you try and slow one down quickly from speeds above 120mph, but a poorly setup STV has a terrible midrange hop, and takes a long time to get to a mediocre top end. The setup window on a STV is a ton smaller than that of the Mirage.

RT

[AnthonySS]

Hey a year ago, I thought the SM was my worst enemy. However with some seat time and some setup tips from the likes of RT, I highly recommend this case now.

I personally would not change a thing casue I am happy that it is a box-stock item. I am looking forward to using it for longer then modified cases I have run...they just did not last! And fortunately for me, the failures where at low speeds...less then 80!

The SM takes some time to dial in...but it is the best case I have run on the STV

...THANKS RT for the tips...The boat runs flater and faster too!

[peedeerooster]

My Mirage ran very well at high speeds in the teens with a CLE. But it had a Bob's cone on it. The problem I had with it was the drain plug hole. It keep burning the paint and bondo behind the whole. I finally cleaned the hole with acetone and filled the hole up and blended it in. It was a little pain because when I would change the fluid, I had to dig out the hole and refinish it. But, It ran very well.