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-   -   drilling low water pick up on a outboard (https://www.offshoreonly.com/forums/general-boating-discussion/240156-drilling-low-water-pick-up-outboard.html)

Velocity Tom 10-03-2010 01:09 PM

drilling low water pick up on a outboard
 
Anyone ever drill a merc. outboard reg. water pick up lower for low water. IE. holes in the nose.

Too Stroked 10-03-2010 01:48 PM

Never heard of somebody simply drilling a set of holes in the standard gear case to make a low water pickup. I have the CLE gear case with the low water pickups built in, and there's a whole lot more to it than simply a set of holes. There are actually a set of removable (to clean out weeds) plates on each side just below the cavitation plate too. I'm not even sure if those passages exist in the standard gear case.

On a related note, most aftermarket nose cones that include a low water pickup include a set of external braided hoses to get the water from below the bullet up to near the old (standard) pickup point.

Velocity Tom 10-03-2010 02:33 PM

This is on a 1995 225. I have a 30 concept that 1 eng idles fine get on plain and it over heats. Looked at the lower one has duel pickups and the one that runs hot only has the ones on the side. Its sucking air.

timewarp 10-03-2010 03:08 PM

As Too Stroked has said you can't just drill the holes in the front of the gearcase, there are no passages up to the waterpump. There is one thing you can try, that is you can plug the upper holes on the side of the gearcase, 2 or 3 on each side so that it won't suck air. You can either fill them with epoxy or drill and tap the holes so you can locktite an allen head setscrew in the hole. If you truely need a low water pickup you would have to add a nose cone to the existing unit.

Too Stroked 10-03-2010 04:30 PM


Originally Posted by timewarp (Post 3222119)
As Too Stroked has said you can't just drill the holes in the front of the gearcase, there are no passages up to the waterpump. There is one thing you can try, that is you can plug the upper holes on the side of the gearcase, 2 or 3 on each side so that it won't suck air. You can either fill them with epoxy or drill and tap the holes so you can locktite an allen head setscrew in the hole. If you truely need a low water pickup you would have to add a nose cone to the existing unit.

Good point - and Mercury even sells special screws (at least for the Sportmaster lower) to plug selective holes.

thirdchildhood 10-03-2010 05:51 PM

Put on a nose cone, plug the uppermost holes and grind on the lower ones to guide water upward. That's what I did on my 2.4 200 anyway.

Velocity Tom 10-03-2010 06:38 PM

Im going to plug the top 2 and try it.

vnemous 10-03-2010 06:56 PM

Well
 
You need to find another case with the stock lwp like the other one you have. If you put a nosecone on it you will lose speed. JMO

blackboat 10-03-2010 07:36 PM

I dont know if this would apply to a newer merc outboard,but 35 years ago ,when we were all running hydrostreams and checkmate outboards a lot of the mercury outboards were overheating due to raising them4 to 8 inches .
We came up with a simple solution by installing a small scoop over pickup holes and waterpressure picked right up and solved the overheating issue.

packinair 10-03-2010 07:38 PM

on my cat for awhile I was having water issues and had low water pick ups on the sponsons and a hose that went up to between the mid and powerhead. worked great


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