Mariner 150 still running HOT.

[rocks]

I need help!! This engine is killing me.It runs hot at 3000 rpms.I have replaced water pump,therms,pop-it has 10 hours on it.What happens is the water pressure builds to over 20lbs at close to 3000 rpms.The first 2 times out this year it was fine unless I ran WOT then it started setting off the horn at 3000.Please help before I unbolt it in 50ft of water.Thanks<br />1993 model

 

[AndyL]

Re: Mariner 150 still running HOT.

20psi sounds a bit on the high side at 3000 rpm. Mybe your poppet valve is hanging on too tight. I don't have the operating pressures to hand but no doubt someone in this forum will be able to give a more precise figure.

 

[heybaylor]

Re: Mariner 150 still running HOT.

Andy is correct ..<br />poppit should "pop" around 2500/3000 then drop your pressure ..then it builds again as you increase rpm,,<br />did you replace the poppit seat ?? they have been known to swell and hold the poppit too tight ..<br />could be that $2.00 item

 

[rocks]

Re: Mariner 150 still running HOT.

Thanks guys,Is it common for the pop-it to go bad so quickly?I took it apart sat. and it didn't look bad at all.The first time the diaphram was corroded and had sand in it.I will go buy a seat and see if it helps.<br />Thanks again.

 

[rocks]

Re: Mariner 150 still running HOT.

Just got back from test run after I replaced popit seat, now the water pressure shoots up to 25-30 psi at 3000 rpm. Any other suggestions? The old seat did look egged,but now it seems the popit will not open at all.

 

[rocks]

Re: Mariner 150 still running HOT.

By the way I have removed 1 bolt from the mounting bracket. Only 3 left.

 

[AndyL]

Re: Mariner 150 still running HOT.

If you originally replaced the poppet valve and kept the old spring I would suggest you cut off a turn of the spring thus making it shorter and hence it should release with less pressure. Practice with your old spring cutting pieces off until you drop the operating pressure to something more acceptable. It would seem to me with all the work you have done that maybe someting else is astray with the poppet assembly. So before making any permanent "adjustments" fully check that you have assembled the unit correctly. The pressure seems very high and obviously you are not getting adequate circulation. Have you actually changed the whole poppet assembly or just opened it up and changed the seat?<br />Andy

 

[KCLOST]

Re: Mariner 150 still running HOT.

You should replace the entire poppet assembly, not just the diaphram... You need to replace the carrier, grommet, spring, washer, diapram, and maybe even the "plastic" poppet itself...<br /><br />I bet that the carrier and grommet are the cause of you problem, they are the parts that are fixed to the block in the hole that the poppet fits into...

 

[rocks]

Re: Mariner 150 still running HOT.

I changed the entire assemby last august the the boat sat up all winter.The weird thing is last month it ran ok except at WOT.Then it slowly started over heating at 3500 then 3000.As soon as this hurricane passes i am going to buy another assemby and give it a try.