Any reason this won't work?

[STV_Keith]

Just had my buddy reseal my sportmaster and put a new water pump in it. He inadvertantly put a 1/2" water tube upper water pump housing on it and I want to go to the water tomorrow. My mid has the 3/4" water tube, so I thought I was screwed...

So I pulled out my 3/4" water tube and grabbed one of my old 1/2" water tubes, pulled the rubber gromet seal out of an old 1/2" water tube upper pump housing and put it over the end of the 1/2" tube, then put that tube and gromet seal up inside the rubber gromet at the base of the exhaust adapter for the 3/4" water tube.

I had to tap it in, so it's pretty tight. Ran the engine on the hose and it seems to be working fine.

Any reason this won't work?

[Scott in MN]

That's the way my 245 has run for years.....How did you get that seal out of the pump housing without destroying it?

[STV_Keith]

I started by putting a screw driver between the housing and seal, then pulling with a pair of needle nose. It did rip a small part of it like that, so I then took the screwdriver and came in from the impeller side and pushed it up.

Thanks!

[Specialized P4-12]

if your running a 260 i would be careful and watch your temp at hi rpm.. i was told never to run a 1/2 tube on a 260.. not enough water... but i have also heard that it doesnt matter.. so.. good luck.. only one way to find out..

[woodduck]

Once when I was married I swapped my 15" mid at home to a 20" I had luying there, it was a sat arvo and I did'nt want to go back to the workshop and get the longer tube. Rummaging around the house I noticed that the curtain rod in our bedroom was the right dia! Jeez I got in strife when she went to pull the curtains and the stick that i"d jamned in fell out! That curtain rod stayed in there for 6 months!

[Scott in MN]

Keith, let us know your results. My 245 hasn't been over 9000 yet so I can't say for high rpm's, but at below 9000 my motor won't see over 120 degrees on the warmest days. When the water is cool I have trouble getting it much over 100 degrees. I had so much water at the powerhead (over 30 psi) I had to modify the water intakes to take in less. At idle is another story though....

[funithesun]

My '92 260's only had 1/2" tubes

[stoker2001]

Kieth,i have been ussing old school 1/2" modded upper WP housings on my 2.5 drag forever
you save substantial $ this way
You have to hacksaw about 3/4" or so off of the chimney to match the hieght of the 2.5 (3/4") one
Make sure the cut is true and square
then you go inside with a high speed air dremel porting bit and hog it out to match the 3/4" one
then glue on the 3/4" adapter/coupler and waalaw you are good to go at a third the cost
dont forget the alighning sleeve

[racer]

Why not just use the liner from a new stock one in the high perf housing?

[STV_Keith]

Worked fine today. A little less pressure than normal, but got me by. I'll get the right housing on it for my 3/4" water tube this week. Thanks!

[MERC SCREAMER]

If the engineers at Mercury Racing wanted to provide a higher volume level of water flow by using the 3/4" tube (in the 2.5 offshore housing / 1 piece plate), then why would they use an essentially stock water pump base with a 3/4" to 1/2" reducer? Doesn't the 1/2" outlet of the water pump base negate the added vloume flow of the 3/4" tube?

I've been wondering about this since last year when I ran 2.5 offshores with CLE gearcase.

[stoker2001]

Why not just use the liner from a new stock one in the high perf housing?
that is an option,but my housings seem to distort from heat in a short time

Externally the 1/2" housings are identical except for the taller outlet/chimney
again,all you have to do is port it internally at the outlet area and it will flow as good as the mega dollar 3/4" HIperf ones

[NICE PAIR]

Kieth,i have been ussing old school 1/2" modded upper WP housings on my 2.5 drag forever
you save substantial $ this way
You have to hacksaw about 3/4" or so off of the chimney to match the hieght of the 2.5 (3/4") one
Make sure the cut is true and square
then you go inside with a high speed air dremel porting bit and hog it out to match the 3/4" one
then glue on the 3/4" adapter/coupler and waalaw you are good to go at a third the cost
dont forget the alighning sleeve

stoker2001 is correct,I've been doing this for years, It works. I just put the housing on the drill press and run a 3/4" drill bit down thru the housing.(don't go to deep) Saves $$$.