Merc 525sc water crossover
 

I am installing water crossovers on my 525sc's. How many of you with these motors run water dumps? Boat runs 90 now, will I have to much water pressure with out dumps? Bravo 1 drives w/dual water pick-ups. Not running t-stats. 1" plumbing.
Thanks for the info.

Re: Merc 525sc water crossover
 

A friend of mine has the same setup in a 75mph 29' Fountain.
1/2" dump lines from the exhaust manifolds through the transom.

Re: Merc 525sc water crossover
 

Not running thermostats, I doubt if you'll have a problem. The restriction will then be in the tailpipes.

Re: Merc 525sc water crossover
 

Make sure you install a restrictor in your thermostat housing otherwise your block may not fill up completly. Plus you want psi to dissipate heat.

Re: Merc 525sc water crossover
 

Only way to know is to install water pressure gauge.
Too much pressure requires a relief device.

Re: Merc 525sc water crossover
 

Absolutely...

My buddy sees between 5 and 15psi depending on rpm. He has a dash mounted water pressure gage. The water temp is still quite cool at these pressures.
Before he added the dumps, the water pressure was 25+psi and the engine ran way too cold with condensation all over it.

Re: Merc 525sc water crossover
 

Does he run a T-stat?

Re: Merc 525sc water crossover
 

Nope.

Re: Merc 525sc water crossover
 

I think I may end up sticking with my circ pumps. My engine man says my motors will not warm up to temp until running WOT. Then dropping down to idle loosing heat and causing condensation in motor,"continueously "thus shortening engine life. Sounds like alot of headache and money for a few extra ponies and looks.
I may have a new set of crossovers for sale! :rolleyes:

Re: Merc 525sc water crossover
 

Smart Choice...
10-15HP is not worth the effort IMO.
The only down side to the circ pumps, that I can think of, is that they don't last real long (100-150hours) when they are run over 5000rpm.