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Block pressure / water pressure

Posted: Thu Sep 17, 2020 8:41 pm
by Mccoy38
OK so new boat to me. 2011 A25 with Merc 8.2. Cobalt smart raft gauges. My block pressure On the smart craft is reading like 65psi at idle and 190 psi at 3000rpm. I changed sensor thinking it was bad. Same. After talking with Merc. They were concerned. Said it should be like 20psi. So I’m now very concerned.

Back flushed oil cooler. Got a little funk out. Did HX. Nothing. Did steering cooler nothing. Both pop it valve balls are bouncing when I squeeze hoses. What am I missing? Anyone else have this set up? What are your block pressure readings?

I have developed a small valve cover leak which got me on this venture. Seeping on manifold. I can handle that bill to fix but temps are all in range on coolant side. So confused.

Re: Block pressure / water pressure

Posted: Thu Sep 17, 2020 10:39 pm
by okielaker
Can the pump make that much pressure? Saw another posting that said a block pressure high alarm
could be a bad sensor or a wiring short... you've covered the sensor... how difficult is it to check the
wiring for a short?

Re: Block pressure / water pressure

Posted: Fri Sep 18, 2020 8:01 am
by cmattj
Have it scanned as it apears your decimal is in the wrong location.
Idle is usually just 1.0 or so ( in gear Idle moving can give you 3psi) and a fresh impeller is usually 15-25psi depending on rpm.

Could just be a bad upstream reading.

Re: Block pressure / water pressure

Posted: Fri Sep 18, 2020 3:21 pm
by Mccoy38
Great point. Freakin our over a decimal. Make sense. I don’t think that sensor is able to detect over 50 psi anyway. Thx.