200 optimax water pressure

[bamspringtx]

1998 200 opti. Just installed water pressure gauge. I tee'd into water line from strainer to fuel rail. Will this give me an accurate reading? I can't seem to find what pressure I should have. I get about 2 psi @ idle, 8-9 psi at 5400 rpm. This seems low to me. The psi was steady, and rose the same as throttle. I never saw it drop then come back up. I'm thinking the poppet might be stuck open?
Thanks,
Bret

 

[gss036]

Re: 200 optimax water pressure

I am not familar w/the opti engine, but your idle pressure seems ok but I would think you should be about 10-12 psi at WOT. It could be where you tied into the water line. If the poppet were stuck open, I think you would have an overheating problem at idle. The poppet opens at about 3000 rpm, so that would not matter at WOT. Could be it is time for a new impeller in the water pump.
I put a water pressure gauge on my carbed 200 hp and tied it into the line coming off the top center of the block behind the fly wheel. That line on mine goes to the poppet assy. The TelFlex site gives goos information on gauges and trouble shooting, I think more so than Mercury manuals.

 

[JUSTINTIME]

Re: 200 optimax water pressure

8 - 10 psi minimum @ 5000 RPM
right from the manual

 

[Don S]

Re: 200 optimax water pressure

Best thing you could do now would be to put in a brand new impeller and see what the pressure is. Then you have a base number with a new impeller.

 

[gss036]

Re: 200 optimax water pressure

My factory Merc manual for my 89 200hp says 12 psi @ 5500, so I would go along w/Don (on suggeting again) to change the impeller so you know where you stand. Especially if it is the orginial impeller.
Justintime, is that a Mercury Opti Manual for that year? I know all seem to have didfferent numbers, really don't understand why?

 

[bamspringtx]

Re: 200 optimax water pressure

Yeah I was going to replace the impeller this season. It is 2 years old. I was also going to replace the poppet assembly. It is original. Think I should mess with the t-stats? They are original. Never been in salt water.
I decided I wanted a pressure gauge, and wanted to see what the #'s were b4 I replaced pump and poppet.