sport

Sorry to here about your bad luck. What broke in your XR drives, were they new XR's or were they rebuilt by someone? I have been thinking about pulling my back cover to take a look at my upper gear set to see if there is any pitting, it has 90 hours on it.

Steve Zuckerman

They were rebuilt by the same person who has been keeping us on the water for years. They just weren't designed to take the horsepower and torque that it's easy make now. It isn't EBM's fault. There is a reason Mercury Racing doesn't put them on anything over the 600s. We've tried every trick we know (cryogenics/special oils and additives/blueprinting/extra HD bearings/high flow drive showers/etc.) The only suggestion I have is go easy on them, use the best oil your builder recommends, have a functional drive shower (most aren't), or buy a SCX IMCO. Change the oil frequently and keep a close eye on drain magnets. It also doesn't hurt to have a good shop or drive technician remove and inspect your drive, whatever it is, in the offseason. I used to say "I would rather pay $500 in January than $3000 in May"......
Best Regards,
Steve

launchpad475

Steve, any pics of your drive? I think I've seen one, you have AN fittings set up on a custom shower cap it looks like? Where do you pick up water for the shower?

Curious, thanks....

Steve Zuckerman

Like most people running Imco SC lowers, my water pressure is very high. The first time I tested with it, I got water in a cylinder.
Now I am taking water off the motor on the back of the intake, a Merc 30PSI blowoff and my drive shower, in addition to all the stock dumps.
I have a tee fitting with an adjustable pressure relief valve right after the WP outlet. It is set to about 10PSI and kicks in at plane off. It goes through the transom with a bulkhead fitting into a braided line a 90o AN (good eyes) and a stock IMCO cap.
If you think about it, the rest of the cooling system is linear to the engines RPM and heat buildup. The more RPMs you turn the more the water pressure builds inside the engine and it's various coolers. Unfortunately with most drive showers, they get less water as the boat rises out of the water at higher speeds, feeding the drive shower intakes less and less. So you get less cooling the faster you go.
You've probably seen some the old helicopter shots from the transom in Hot Boat and Powerboat. In most of those pics, there is no water coming out of the drive shower ar WOT. At the least, my setup is also linear with engine RPM and boat speed. Obviously it isn't perferct because I'm still blowing drives, but it's the best thing I've seen so far. Some west coast guys (?) have a pretty cool oil pump and inboard water cooler system. I have never seen one run by anyone here.

launchpad475

Thanks Steve, sounds like cool set up. I don't have the helicopter budget, so the go-pro on a stick had to work. Up to about 50 I have tons of water, I've made a few adjustments. Above that who knows, it's tough to see the video at WOT there is exhaust water spraying everywhere... Plus I don't want to be hanging off the back any faster than that!

Steve Zuckerman

Great picture. I am going to mount my Go Pro under the swim plaform next summer for a simlar view.
I don't know if there is amything there to be leared from it other than the flow, or lack thereof, from the drive shower,
But there might be, like flow off the tabs and drive, etc.
Oh yeah, I also mounted the 30PSI Merc water dump line under the swim platform so it sprays on the drive too, when
it blows off. I figured every bit of cooling I can get would help. I even thought about plumbing a second braided line from the
dump to the drive shower cap.