Water pressure at WOT on 150 mariner??

[rocks]

Have had an on going overheating problem.Last time out pressure spiked at 25psi then alarm at 2500-3000 rpms. Was wondering what normal psi should be when popit opens.I think mine may be sticking shut.

 

[LubeDude]

Re: Water pressure at WOT on 150 mariner??

KCLost Seems to be the water preasure, popet valve specialist here, my water preasure on my 150 Merc runs at about 18 PSI at WOT.

 

[rocks]

Re: Water pressure at WOT on 150 mariner??

That tells me mine is running too high.How long can I run with the alarm going to see if it will come down?

 

[LubeDude]

Re: Water pressure at WOT on 150 mariner??

Originally posted by rocks:<br /> That tells me mine is running too high. How long can I run with the alarm going to see if it will come down?

Without a temp guage, I wouldnt run it at all.

 

[KCLOST]

Re: Water pressure at WOT on 150 mariner??

If you are having 25psi at 2500-3000 rpms you most likely do have a poppet valve problem... Sticking shut or clogged up with debri....<br /><br />You should see the poppet open around 15-18 psi at around 2500-3000 rpms... <br /><br />However, your wot pressures will still increase above that range even after the poppet opens.. 20-25psi is normal... At around 5600-6000 rpms... Maybe a little lower is also normal because of your hp, which is mainly due to your gear ratio in the lower unit... 150hp pressures will be lower vs. a 175hp and 200hp....<br /><br />But before you carve that in stone, what year is your motor?

 

[andy6374]

Re: Water pressure at WOT on 150 mariner??

The poppit is easy to inspect. Just remove the 4 bolts holding the relief plate cover on, located on the starboard side just below the ignition plate. Something could be stuck in the spring, not allowing the poppit to open.<br /><br />It opens at around 3000RPMs. You should see a steady increase in water pressure and then a sudden drop when the poppit opens, if there is no pressure drop the poppit is stuck.

 

[rocks]

Re: Water pressure at WOT on 150 mariner??

It's a 1983 150 mariner.I have replaced pop-it last year and it ran for a few months then back to alarm.I have inspected and is clear and clean.The only part of the popit i haven't replaced is the spring.Allother,diaphram,seat and therms water pump have been relpaced.