Low-water pick up question

[diamond-back]

Here is the current height set-up with our engine:
http://www.cafes.net/corywurst/details.jpg

The details for the set up are:
'04 225X Mercury Promax
23" 4-blade Trophy
6" offset jackplate
Torquemaster lower unit
75mph (GPS) @ 6800rpm

My question simply is . . . how high can I go before I need a low-water pickup? Should I modify my lower unit, or get a Sportmaster lower unit?

[beer30]

You should have a water pressure gauge on the boat, as soon as that below 10 lbs., you will have a problem. Watch the gauge that will tell you how far up you can go. Move the engine in 1/4" increments till you get to that point. :) Chuck.

[SportJ-US-1]

Here is the current height set-up with our engine:
http://www.cafes.net/corywurst/details.jpg

The details for the set up are:
'04 225X Mercury Promax
23" 4-blade Trophy
6" offset jackplate
Torquemaster lower unit
75mph (GPS) @ 6800rpm

My question simply is . . . how high can I go before I need a low-water pickup? Should I modify my lower unit, or get a Sportmaster lower unit?

Normally 6" of setback will give you an additional 3" of engine height and still be concidered normal height. If you water pressure is good where you at you are only an 1 1/2" up in reality. With regular pickups I have been up as high as 5" with no water pressure problems on a V-bottom and 7" on a true tunnel. The water pressure gauge is concidered to be required for any raised engine heights, get one before you do changes and confirm your water pressure is ok now, because theory only works sometimes as it is only a guess based on what is known about other setups, not yours.

[Fish]

good advice above just might add that you are already turning your 23 at 6800 rpms, you might need a little bigger wheel if you start going up. definitely get a water pressure gauge. Does your Tourquemaster have side water inlets that are open or are any of them plugged? You can get bob's to add a cone to your TM for a few hundred bucks if you don't want to go the sportmaster route.

[hsbob]

get the low pu. it will cost you 1-2 mph, but i'm running a 200xs sportmaster with the prop shaft efven with the bottom and still have 20psi. its been even higher w/o problems. oner heat that motor a sew times and your looking at $$$$.


at the very least plug those upper tor-master intake holes.

[TheRickster]

You can also add the Mercury "Scoops" to the Torquemaster. This will increase your water pressure greatly. I was at 10-12 lbs. with mine and added the scoops and now it is 18-20lbs. at the same height..

Rick

[play2win]

What is the purpose of the torquemaster lower unit upper intake holes? And why would you plug them for better water pressure? I had an 82' merc for 23 years with no problems, and burned it up this year. Looked down at the gauge, and it was less than 5, dont know why, but it was too late. I now have a TM on a new 2.4 block. Will plugging holes prevent this? What about lwp?

[150aintenuff]

play2win it sounds as though you lost an impeller or it had takes set if you had good pressure before and lost it at the same height... I use a WP gauge for just that reason on my fissin boat that is mounted direct to the transom... as an indicator of impeller condition...

As fer the height I would say that LU SHOULD have the front low water pickups at the level of the bullet already... SO plugging the top holes ONLY keeps the water column form falling out the holes and starving the pump. if youi have the 4 water intakes on the front of the bullet you can plug all but the botton 2 side holes and run her WAY up and still keep preasure.... they were designed to be ran up 4-5" higher(1.5-2.5 Below center) than a factory case because of the front water pickups...

[Rickracer]

Please forgive the crude L/U graphic, it was quick and easy, but it gets the point across. Boat and trim at level (pad or keel and propshaft perfectly horizontal), plumb bob or similar from rear (wetted) edge of transom to ground and front edge of L/U to ground. That is total setback, and covers all variables between SS and standard mids, notched transoms, etc. :cool:

[Jimbo]

Before you spend the money for a low water pickup gear case use some of the tricks listed above. Be sure to get that water pressure gage if you don't have one now.

You will at the same time need to change your prop to keep your RPM's just below the rev limiter. You can maximize your speed by going to a higher pitch prop and efficiently using all the horsepower built into your motor. Also, as you raise the motor ; you should be able to run the motor at an efficient trim angle for max speed. If you lose the ability to trim the boat as you raise the motor the you will have to lower the motor to a more efficient height.

If after experimenting with all these changes you still need a low water pickup, then the best solution is to have Titus or Bob's put a cone on your existing torquemaster case. The torquemaster internals are the same as the sportmaster case and they can customize the profile of the case ( within limits ) to fit your application.

Jim

[Bruster]

You can also add the Mercury "Scoops" to the Torquemaster. This will increase your water pressure greatly. I was at 10-12 lbs. with mine and added the scoops and now it is 18-20lbs. at the same height..

Rick

Are they still available?

[slikcraft]

have anybody a pic of the scoops

thanks

[drasticplastic]

Ithink that they have pics at www.mercurypartsexpress.com (http://www.mercurypartsexpress.com) in the accessories section.

[hsbob]

i have not had sucess with the scoops, still over heated the motor. i've lost 3 200hp to overheating and dont want to again. put the low water pu on and be done with it. ok so it may loose 1-2 mph [raising the motor may regain that] is cheap insurance against $5000 repair and down time.

[Steven]

i have not had sucess with the scoops, still over heated the motor. i've lost 3 200hp to overheating and dont want to again. put the low water pu on and be done with it. ok so it may loose 1-2 mph [raising the motor may regain that] is cheap insurance against $5000 repair and down time.
same here. 19 liberator 200 merc. lows 80s boat but i still have to have the lwp. i tried the stock case with the top 4 holes plugged, trim up forever and overheat and slower. really glad the overheat buzzer worked!!!! im amazed at how raising the motor up, even 1 hole, changes the way the boat runs.

[150aintenuff]

$30 fer temp gauge, $40 fer water pressure gauge... THERE IS NO EXCUSE FER OVERHEATING!!!! AND the torque master HAS a LWP in adition to SIDE pickups ya can plug ALL but the bottom 2-3 and maintain enough water FLOW and PSI to effectively cool that motor.. spend money on gauges and start raising it up