gearcase info wanted

[check88]

was wondering what is the fastest anyone has run a 200 style gearcase without a nosecone and without blowout?i am considering removing mine and either using the side scoops off of a torquemaster case to help with water pressure or going to a transom mount water pickup.i have a bobs torque tab on the skeg that i have modified by adding about 1/8 inch of material to the trailing edge to help with steering torque.i am running about 1/2" below the pad now and was going to raise the engine maybe another 1/4".my thinking is that by removing the nose cone i should be able to get better bow lift and therefore more speed,right?what would the removal of the nose cone do to the handling?this is on a 21' checkmate with 12" of setback running a 26" chopper.thanks.

[us1]

There’s only one way to find out, no, I’m just kidding. I bet Raceman would know, some of the old racing classes used to run clubfoot units.

[jerry]

how fast does it go now ?

[Flat Out]

I run a 200 Johnson with a stock case at 27" of transom height. I run 75-80mph. never had a problem. BUT the OMC case is a couple of inches longer than a Merc one. Glenn runs 72 on his 'Stream w/stock 78 case.

[jerry]

no nose cone !!!!

[Glenn]

Yup. 72 on GPS with no cone. I'm pegging the water PSI gauge and the engine is running cool. I'd go higher put the plate is maxed out. The engine is crabbing a bit and I've had some mild blowout in the past. Usually it runs just awesome. Probably run better with a tourque tab. Not bad I guess for a 23 year old lower unit.

Glenn

[check88]

hey jerry, right now it will run from 68-70 on the gps depending on how much fuel is in it.i guess what i am really trying to find out is what is the max speed you can run one of these cases without blowout.

[MTCM]

I ran an 87 V-King YT with a "bone stock" 175 Merc back in 1988. The boat spun a 28 "big ear" Merc Chopper to 82 mph @ 6200 rpm. The stock gearcase performed very well even at that speed. The only drawback was with the engine at that transom height when the water "chopped-up", even slightly, the engine temp would go up. After adjusting the jackplate (manual) down slightly, the temp problem went away in the choppy stuff but the speed dropped to 80 mph. As far as handling goes with the stock case, it was excellent. I have always heard that the stock cases could reach 90mph without blowout. I can support Flat Out's observation on the OMC gearcase. I had the opportunity to drive a Victory Performance VP-1 back in the late 80's that had a stock 235 Evinrude with a stock case to 90 mph without blowout! This was a 20 foot boat with a stepped center pod/pad with deep outside sponsons. It is my observation that the "average" hotboater with something less than a hi-performance or race engine runs a nose cone (with LWPs) so the engine can be at a sufficient height to maximize performance with the available horsepower without loss of water flow/overheating. The lighter hull-higher horsepower boats running over 100 mph with the nose-coned and CLE/Sportmaster cases are realizing the benefits of these designs that provide "blowout protection". Of course there are other mods to the case that provide blowout protection. I understand the theory on those but do not have the expertise/experience to explain those mods. Some of the other guys on here can educate us on that. With your particular combination I believe that you will be in the "overheat zone" before you reach blowout speeds with a stock case.

Wayne

P.S. In the early 80's I ran a 1979 Checkmate Exciter to 80 mph with a Stock Merc 225. The engine was mounted directly to the transom and the gearcase was stock. It was a handful to drive though. Take Care.

[jerry]

guys , the stock case should be able to break 80 if ts not trimmed to much. if your boat is crabbing and blowing out before that speed , you probally have it trimmed to much . how much set back and what props are you guys running?

[Glenn]

I'm running a 26 Quicksilver Chopper (A5) with the weed cutters. Manual plate with 6 inches of setback. Shaft is a little less then 2 inches below pad (I took a rough measure last time). Tach only goes to 6000 and I peg it routinely. Stock case with 2:1 gears, it’s a little beat up. It run’s 71.8-72 GPS. Last weekend after changing the mounts the water conditions were perfect and I’ve never buried the tach so deep. It was one of those perfect runs. Of course I didn’t have my GPS. Maybe that’s why.

Glenn

[Ray Neudecker]

I have run 90 with a stock OMC gearcase without blowout. This was on an Allison xr2001 with 8 inch setback. 92 on a XB2002 with a stock Mercury gearcase. The Yamaha will blow out at 84. there are many factors such as weight, setback and engine height which affect blowout speed.

[Promax300]

glenn , try lowering the motor one hole , just for ****s and giggles , how is the bow lift ?