what it good water pressure........
 

my gauge will peg out with 35. Is that a problem?

20-25 is good 35 is too much.

When I am at idle my gauge only shows about 2 lbs, but when I'm running at 3,500 or higher the gauge shows about 15-20lbs.

I just cleared my system of some debris that I've had in there for years and now it pegs at 35 at near WOT and over at WOT. Sucks to have a clear system that is not working properly - design flaw? Seems I'll be installing one of those check valves.

In my opinion, it's that POS 2 hose t-stat housing causing all the problems. I installed the Merc relief valves to bring my press. down from a pegged 35 psi to 20 psi.

Yes my system is clear also. I have lightning headers thinking that might be part of my prob. I called Lighting all they said was" good luck with that" they are some Muthr F@#kers! No wonder most evryone runs CMI. I have four hoses in my t stat housing. I talked to a pro. Mech he suggested running a hose from one of the plugs on the t stat housing so water would run from that to the outside of the boat. Im not so thrilled about drilling holes in the side of my boat but do not know what else to do. How do those valves install?

Just slip them in the hose right before the stat housing.

I didn't want any holes either for the discharge, so I installed bungs on the exit side of my silent choice divertor valves behind the butterflys and dump the water out the exhaust.

Thanks for the pics. I paint cars for a living not much on the mechanics side of things. There are two "plugs" on my t stat housing if I attached a water hose to one of those plugs are routed it out would that relieve water pressure?

US1 Fountain;2631904]Just slip them in the hose right before the stat housing.

I did those like US1 and never looked back...

where can you order them from?

Not if you like blown intake or head gaskets. Around 20 to 25 at wot

Another risk from high water pressure!!!
 

I broke the plastic top off my sea strainer running 35-45lbs. If not for installed shutoffs for flushing it would have sunk during the Chelan Poker Run. I raised the pick up so it is level with the bottem and it lowered to 20-25lbs. also I am installing a pressure relive valve onto strainer.
Rick

NOBODY LIKES BLOWN INTAKE/ HEAD GASKETS!
I would like to take this time to thank evryone who chimed in on my problem. once again THANKS! :D

cant seem to find part on BAM marine. What is it called?

I'm glad I'm not alone here. I'm going to install the relieve valves this winter. The boat is away from home right now and a bit hard to work on. Just have to keep it off WOT and below 25 psi :mad: until then.

Thanks.

:eureka: I remembered that I saved a Pic someone posted last year...Don't be shocked at the cost, Merc is very proud of them.

Been there! Spent 1/2 the summer at cruise speed as my WOT while I was screwing around with different housings, hose dumps and what nots with zero luck. Got tired of it and bought the relief valves and couldn't be happier. On the positive side, I saved alot of gas! :) I did buy new springs to lower the pressure even more. I think the relief valve still comes in at around 30psi as a max, but I wanted 20psi as a max. New springs for under $10 and all is perfect now.

Back4More also did the spring change over for best results.

US thanks for the info. I could only get up to 40 mph at that speed was 25 psi water pressure. I have to figure out where to dump the water dont like the idea of water flowing out the side of my boat.

depends on which engine and mangement system you have. some require high pressures like yours. otheres do not. was this the original readings or was something changed ergo drive, engine, cooling system mod's , etc,,,?

It was like this when I bought it back in 2006 I never had a performance boat before so I nevr knew what the water pressure was supposed to be at. It has roller rockers, MSD ignition, Arizona Speed marine ECM Lighting headers. When running WOT the water temp gets to bout 178 while running. Monstaa good to see ur still on the board. BTW it is a 502 MPI.

yes... it depends.
I tried an IMCO shorty and water pressure drops below 25 with positive trim which sets off a fault and kicks into guardian mode.
Merc says the 600sci needs 25-45 with 30-40 ideal.

Would that be the same for my 575sci?
Rick

Don't know. If the 575sci is not closed cooling that may dictate other requirements. I called merc to get the skinny on mine.

no so cal. the 575 doesnot have the same monitoring abilities as the late model equipment from merc.

the psi may be a litle high for an mpi.
look thru the cooling system for obstruction in spots that would seem obvious so over looked. then in the not so in yur face areas. being thorough will yield great results. like makeing sure a 1 inch bung isnt 1 inch od with 1/2 inch id. stuff like that builds pressure causeing high pressure, which will make for airation in the cooling system and improper levels of heat saturation.
coolers, stats, small hoses on exhaust are an easy start, and help make fr good maintanance.

and thanx, i get busy sometimes and get pulled from the board here but i manage to rteturn.

good luck

I changed my T stat even drilled 3 3/16 holes in it. No change in anyting. I did notice that the hose from the T stat housing to the circulation pump is hot also the hose to the header on the same side (starbord) is hot also. Any advice on what to check? Could T stat housing be bad?