Quote:
Originally Posted by Tom Stone
how successful do you think the expansion tank for the gearbox oil is?
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Tom,
I was out for my Job, and didn't see this thread before now.
We have had problem with standard gearcase using bob's nose cone on merc 2.5 and power lift, the bob's nose cone is an extra aluminum piece spot welded and epoxy filled onto the front of a regular gearcase as everybody knows, the problem is the lack of contact between the water/the cone/ the space between the regular gearcase and the oil. this leads to a oil builtup pressure wich cannot expand and leaks trough the reverse oil seal, and sometimes by the shaft seals under the water pumps(especially on 3.0l SM).
This simple mods for the 2.5l , is perfect for us, and we didn't have anymore water inlet in the gearcase since we modify this, the system is working pefectly to 75mph on the 2,5 merc.
For the 3.0l SM 250/300XS and the Pmax 300/300X the parts are differents, you need a billet support with 4seals from MADEFI under the water pumps, and a billet or a modified seals support for the shift rod, this one is billet from alu/2seals with Lakeland marine, or original plastic modified to receive 2 seals also,and on both you have a plastic line , plus a expansion reservoir.
It's better for sure to have the stainless steel elbow fitting directed in aft direction (for the question concernd to the 200XS onanother forum cited above), but not so important, the pipe is Heavy duty one, as this part of the gearcase at hi-speed is out ouf the water.
Added pictures, are for the 3.0l, on the 2.5 we don't use the shift shaft as it's not the same, and also no billet 4 seals supports, as they are for the SM 3.0l.
for the 3.0L SM check this link:
http://www.yamaha-rebuild.com/Merc%20high%20perf.htm
http://www.madefi.com/
http://www.mercspeed.com/index.html (better to call or mail for this one)
hope this help...
Linear Mode
