Ok, What's up with my poppit

[dingbat]

I’ve got a 1986 Merc 175 Black Max for whatever reason seems to eat poppit valves. I end up replacing parts of the poppit valve on a regular basis anymore. <br /><br />Two years ago it was a complete rebuild but last spring I replaced only the spring and the diaphragm only to have a spring fail in late fall. This spring I had good water flow out the pissr on the first outing but after that I only had a dribble at best. I had good water pressure (15-16 psi) and good water flow out the prop and exhaust ports but just couldn’t get a decent flow out the pisser. I pulled the stats and cleaned them and even blew out the water hose running to the pisser but still nothing. I even removed the poppit valve and back flushed the system with a hose but nothing seemed to help. Finally in desperation I changed out diaphragm in the poppit and it nows shoots water about 4’ across the drive. Everything has been good since but I’m wondering why I’m having all these troubles with the valve. Has anybody experienced similar problems?

 

[KCLOST]

Re: Ok, What's up with my poppit

Hmmmmm,,,<br /><br />4' across the drive!!!!! Mine's never done that on the ear muffs and I have the same engine same year. Does it do that just after start-up or after it has ran for a while?<br /><br />This has me very interested. I never have any good water flow until the t-stats have opened. Until that time I basically have a dribble or weak spurts like you mentioned. You can even see when myu t-stats start to open up, and then the water flow is is at least consistent but pretty low. But when they are fully opened, like after a run or long period of time at no wake speeds it will shoot out of there like a fire hose. <br /><br />By the way, do you have a temp. guage?

 

[dingbat]

Re: Ok, What's up with my poppit

Right at start-up I'd say maybe 12" or so but once the stats open up she really lets go.<br /><br />I’ve never really had a temp problem so I never installed one. I’ve run 10-12 miles out to fishing grounds, troll at 800-1000 rpm for 6-8 hours at a time and then head back to the dock and was still able to hold my hand on the heads. Other than this darn poppit thing I’ve not had any real issues with the cooling system

 

[KCLOST]

Re: Ok, What's up with my poppit

How long can you hold your hand on the heads, forever?<br /><br />As far as the poppet goes, are you absolutely sure you have all the parts installed, and installed properly?

 

[KCLOST]

Re: Ok, What's up with my poppit

Take a look at this link...<br /><br /> poppet<br /><br />You should have the round poppet style that shows part#'s 6-15.

 

[dingbat]

Re: Ok, What's up with my poppit

I've taken this thing apart so many times that I could assemble sleep. Besides, if it was assembles incorrectly why would it work for 6-8 months at a time before taking a dive?<br /><br />I've never timed it. The way I fugre if it's anything even close to 180 it's going to burn ya almost instantly. If I had to guess I'd say somewhere around probably around 160 or so.

 

[KCLOST]

Re: Ok, What's up with my poppit

Saltwater in the mix...?

 

[Bob H.]

Re: Ok, What's up with my poppit

My experience with Merc's of that vintage is that the company doesn't have a clue. I've bought several poppets recently and ended up with valves of different lengths and springs that don't work properly. I ended up just replacing the diaphram and had to reuse my 1987 spring. The new springs are junk.

 

[dingbat]

Re: Ok, What's up with my poppit

The boat has never ever seen freshwater let alone been floated in that nasty stuff. <br /><br />I guess the only thing left to do is a buy a complete new housing assembly and see if that makes a difference. The existing housing has some minor erosion on but the sealing surfaces look to be intact. <br /><br />I had a new spring fail on me last winter. It was 26 degrees and dark and I had 3 guys on board ready to go fishing when my water pressure dropped out. I certainly wasn't any too happy about hanging off the back of the boat with freezing hands to change a poppet spring.

 

[gss036]

Re: Ok, What's up with my poppit

I am amazed you could do it hanging off the back of the boat. What is the secret?<br />I have an 89 200hp and have been trying to figure out how to access the poppet just to take a look and maybe change the diahpram. I have a post going about removing the lower cowling to gain access.

 

[dingbat]

Re: Ok, What's up with my poppit

Remove the lower cowling? I only have left and right side “Clam shell” type covers. <br /><br />I remove the front trim cover and then release the two clamps that hold the cowlings together. You swing the cover out and lift it off the back hinge and set it to the side. Once the cover is off I tilt the motor to the full up position and the poppet is staring you right in the face.

 

[KCLOST]

Re: Ok, What's up with my poppit

dingbat, I understand your pain.... I would recommend replacing the outer and inner plates. It won't hurt... But on the spring issue, I'm not sure what is going on there...<br /><br />However, remember that if your poppet fails again (and you know that is the cause of pressure loss) You can run that motor wide open and it should not overheat.. It will at least get you back close to the dock or ramp..

 

[Bob H.]

Re: Ok, What's up with my poppit

I've found that the best springs are in the junk yard. Merc obviously went to the low bidder a long time ago. At $.50 each I bought 5 "new" Merc junk springs. A trip to BoatDoctor and a spring from beat up 1987 cured my problems.