Water pressure opinion

[catiiid]

I have a 1994 200hp Mariner. I recently noticed the water pressure had dropped and on the last trip out at high rpm the warning buzzer went off. I changed the water pump impeller, when I installed it I applied a light coat of grease on it to protect it on initial start up. Do to lack of time I just backed it down the boat ramp and started it at the ramp. I only had 4psi at idle. Run it to 1000rpm and gauge went up to 10 psi and looked like it would go up higher but I didn't want to rev any higher in neutral. My concern is at idle. I had 6psi before I messed with it. Will the pump get better as it breaks in? Is 4psi okay? I won't be able to give it a good run until next weekend. Thanks for any help.<br /><br />ED

 

[emckelvy]

Re: Water pressure opinion

Maybe you have a problem with your thermostats and/or poppet valves.<br /><br />I'd replace the thermostats and also all the poppet components, including the poppets, springs, diaphragms, and grommets.<br /><br />I'd think that even 4 psi at idle, as long as there's adequate indication of flow out the telltale, would be OK. 10 psi at 1000 rpm is certainly more than adequate and it indicates the impeller is pumping properly. <br /><br />I wonder if maybe one of the poppets has debris under the seat or is otherwise leaking by, that'd be one possibility which could cause a low-pressure-at-idle condition.<br /><br />HTH...........ed

 

[catiiid]

Re: Water pressure opinion

Thanks for the info. I will give it a run next week.<br /><br />ED