1982 150 poppet valve questions

[fishingdan]

ser 6010145

I want to replace my poppet valve and after looking at it, I have a couple of questions.

1) My Seloc manual has no section on maintenance for this part. Am I missing it somewhere?

2) While the serial number on my engine indicates that it is a 1982 engine, the poppet valve diagram (engine block diagram) on Mercury parts express.com shows the part differently than what I see. On the diagram, the poppent valve cover is basically a circle. On my engine, the poppet valve cover has an appendage that extends back (in the direction of the cylinder head) a couple of inches. I took the cover off and the appendage covers a cast recessed area in the block that is about 3/4" in diameter and about a 1/2" deep. There is no opening in this hole. What is the purpose of this recessed area?
3) Given that my actual part doesn't match the diagram online, how do I find the parts for this? I am guessing that the internal poppet valve parts are the same, but the cover gaskets are different. Maybe this engine has a rebuilt powerhead.

Thanks

 

[gss036]

Re: 1982 150 poppet valve questions

I think you have a rebuilt/different power head. I bet your poppet is kind of a modified figure 8 shape.
Try looking at the parts usingSR# 0C198948 and see if that looks like what you have.
I don't know if they would be same or not, probably not.
Does'nt matter, you are going to end up going to a Merc dealer to get the parts anyway.

 

[fishingdan]

Re: 1982 150 poppet valve questions

Yes, it looks very similar to that, but it mounts horizontally. The smaller end mounts toward the cylinder head on my block.

 

[ncfish1]

Re: 1982 150 poppet valve questions

Fishingdan; Your relief valve cover should have a hose connection that feeds to the end that has the cavity that goes no where. However, there is a small channel that allows flow between the cavity and the poppet assembly by way of the cover plate. The relief valve cover plate part number is 68729 if it is the figure-8 cover mentioned by the earlier thread. If you have this type assembly, then you should need 12 items that make up the entire assembly....2 gaskets, washer screw, washer, diaphragm, deflector, plate, spring, another washer, poppet, grommet and carrier. The poppet assembly can be purchased through any Authorized Mercury Dealer. Parts are sold as separate items except for the gaskets and plate that (I believe) come packaged together.

 

[fishingdan]

Re: 1982 150 poppet valve questions

ncfish,

Thank you very much. It not only answered the current quesition, but also the next. As I was looking at the part, I was trying to figure out how it functions. The cavity under the relief valve and the passage to the poppet assembly was throwing me off. As it was currently setup, I couldn't see any purpose for the cavity other than a volume of air.

Here is why, the relief valve is currently a brass plug on my engine. There is no hose connected to it. If this is a 1990ish powerhead on a 1982 engine, maybe they didn't have any place for that hose to connect to and chose to plug it instead.

Where would the hose on the relief connect to if it were there?

 

[ncfish1]

Re: 1982 150 poppet valve questions

The inlet hose would connect to the small end (it faces the head) of the relief valve cover plate. Water enters the hose, into the cavity you referred to, through the small passage between the small end of the figure-8 of the poppet cover and through the poppet to the motor. From there it passes down through the power head and down to the exhaust cavity where it maintains the "wall of water" in the exhaust cavity for high speed operation. Without the correct "wall of water" the motor will have a louder exhaust sound and can/will create steam pockets.

 

[fishingdan]

Re: 1982 150 poppet valve questions

Thanks again ncfish. After reading your post and looking at the inside of the cover, I can see how some water can travel around the poppet on this assembly. I am still confused as to what the source of water should be.

In the picture below, are you saying that a hose should connect to where you see there is currently a brass plug (assuming the brass plug is not supposed to be there)?

 

[KCLOST]

Re: 1982 150 poppet valve questions

Yes,

THe hose connects to the brass plug and goes up to another fitting that should be behind your flywheel at the top of the block.

It was designed to allow any air pockets that could form at the top of the block escape. The flow of water from the top of the block after the air is released serves no purpose. So the flow is from the top of the block to the poppet via the hose.

 

[ncfish1]

Re: 1982 150 poppet valve questions

The brass plug location is where the hose connects via a 90 degree "L" connection. The hose originates from the very top of the power head centered with the exhaust plate. It's odd that you have a poppet assembly that would not be functional? The relief plate pictured is the figure-8 and in order to pass water through the poppet, there must be a water supply from the motor. I believe the hose is 3/8" rubber between the relief plate connection and the top pf the power head.
Have you had problems with overheating at high RPM's? You should with the poppet not connected.

 

[fishingdan]

Re: 1982 150 poppet valve questions

Thanks kcost and ncfish.

That is a good question regarding the overheating. No, I have not experienced any. I have a temp gauge, but no water pressure gauge. I started to dig into this as a result of the tell-tale not flowing consistantly. I have a new water pump, thermostats and now I was looking into the poppet assembly.

I can't explain why the brass plug exists. I have to look at the engine, but I don't remember seeing any plugged fitting at the top.

I am starting to think that this all gets back to the fact that this engine probably has a rebuilt powerhead. If so, could it be that the exhaust plate from the old engine was used. As a result, it didn't have an outlet and they chose to plug the poppet cover???

I will step out and take a picture of the top of the powerhead.

 

[fishingdan]

Re: 1982 150 poppet valve questions

Here are more pics of my engine. I looked all over the block and I can't find any obvious port where the a tube from the relief valve might connect to. Any thoughts based on what you have seen in the past? Does this tube need to be connected to a source of water or is it connected for water to exit the poppet valve area? Thanks in advance.

Dan

Poppet valve area on lower starboard side of block:

Top of block, starboard side:

Top of block, center view:

Port side of block, tell tale tubing:

Back of engine looking at thermostat hoses:

 

[ncfish1]

Re: 1982 150 poppet valve questions

On the "top of block, center view", I believe I see a plug inserted in the casting that stands up below the flywheel cover? That is where the hose fitting should be located.
The hose from this fitting supplies water to the poppet area and exits through the power head internally to the exhaust cavity. Unless there is an inlet port within the relief housing (aside from the poppet port), then there has to be a water supply if the poppet is to be active.

 

[fishingdan]

Re: 1982 150 poppet valve questions

Thanks again ncfish. I don't see any port in the relief valve housing. The only port is the hole where the poppet valve pokes through.

There is a plug in the casting on top as you have noted. I will look around the various engine diagrams on the mercury parts site to see if I can find that part that should go in the plug hole on the top of the block and the parts for the relieve valve cover. If they are not available, I suppose I can also look for standard brass plumbing fittings.

ncfish, thank you again for all of your responses. I really appreciate the time you took to answer my questions.

I want to repower this boat at some point, but the compression is still good across the cylinders and it seems to be running well at this point. Hopefully, I can get this cooling plumbing to a point where I feel comfortable. Again, the engine hasn't overheated (by watching the gauage or by touching the block exterior). Basically, the first phases of my project boat have been spent correcting earlier repairs.

Dan

 

[ncfish1]

Re: 1982 150 poppet valve questions

You're very welcome. Hope you find everything to make the poppet a functioning part of the motor. The Mercury you have is tuff and should give many years of service.

 

[Capt. Crunch]

Re: 1982 150 poppet valve questions

Fishingdan, I'm rebuilding mine tonight. Here is the hose I have connecting to the fitting on the "blank" looking side of the assembly. I tinted it red in photoshop to trace it easier in the pics...

Hope that helps. If you need any more pics, just let me know. My old diaphrgam was shot and I replaced most of the parts listed above, but after reassembly, I had a weak tell-tale stream and then no stream. I have a feeling I'll be back in the poppet assembly tomorrow (did the water pump rebuild last night).

 

[gss036]

Re: 1982 150 poppet valve questions

If it anit broke, why try to fix it? I agree that you could "maybe" get a poppet installed, if you can find the right parts, but getting that plug out of the top of the block might be the real challenge.
If you go that route, might as well put in a pressure guage as it goes into the same plug outlet.
The post with the red hose had not been posted when I started this post. It looks like the red hoses come from the thermostat housings, not the top center of the block? What year is the motor? Don't know if that is right or not, not on the newer blocks anyway.
Your thermostat hose connects to the pee hole indicator on the left(port) most connect to right (starboard side), it must push water back into the block and down the exhause? I'm confused looking it myself at this point.
Looking at your last picture, I see awire on the right (starboad side) that is a single wire, that is your overheat alarm. The port (left side) has 2 wires showing, that will be your temp guage sender.
I am back with you on this one, that just maybe the older 82 models did not have a poppet and there is a different water channel for the water to exit at high speeds.
Maybe some will read this and jump in with the right information.

 

[fishingdan]

Re: 1982 150 poppet valve questions

Good information guys, but now I am confused as well.

My engine is a 1982 (per the serial num on the bracket) with what I think is a newer powerhead (1990ish??). However, I have looked all over the block hoping to find a serial number on it and all I can find is the firing order.

One explanation for the difference above is that maybe the cooling hoses on my engine were not put back on correctly when the power head was replaced. I am big on the "if it aint broke don't fix it" concept, but something is not right on my setup. I have almost no stream of water out of my tell-tale, yet the engine is not appearently over heating at idle or high-rpm.

Some separately mentioned to me that the hose from the relief valve cover should go to the starboard thermostat fitting as pictured in Capt. Crunch's photos.

Capt. Crunch, how is your tell-tale connected to the block? What year is your engine? Are the cooling hoses setup in the original configuration?

On my engine, it doesn't make sense to the me that the tell-tale would be connected to two points (the port thermostat and the bottom of the block on the port side). However, they look to be in the right spots depending on how one interprets the diagrams at mercuryexpressparts.com.

 

[gss036]

Re: 1982 150 poppet valve questions

Dan, your engine is set up the same as my 89 200hp and the Merc factory manul. You are missing the outlet at the top of the block that KCLOT mentioned above. If you were to make any changes in your current system, that would be the direction I would go.
BUT! That does not solve the PEE stream problem. I hate to even sugget it but since you had a good stream shortly after you did your water pump and new stats, I would take a 2nd look at the water pump installation to make sure that something did not come loose and while you have the lower end off, plug a hose onto the tube going to the bock and run higher pressure water through it , maybe something is blocking a passage.
The poppet would not solve that problem as it holds water in the block until you reach about 2500-300 rpm and about 8-9 lbs of water pressure, it then open and diverts the water down the exhaust.
I have connected a hose to the pee hole once in a while just to make sure it is clear, I would be curious as the where the water exits when you do that. Should go back through the block and out the exhausts.
With all the rust I see I would not rule out a rusted out exhaust section. Also, how is your head gaskets?

 

[ncfish1]

Re: 1982 150 poppet valve questions

Dan; the previous thread is correct regarding the tale-tale stream. Let me get the piping out of the way, then suggest an easy test for the tale-tale.
The piping diagram shown by capt. Cruch for the poppet serves no purpose as connected. To connect the relief assembly to the down-side of the t'stat doesn't do anything for the poppet. The t'stat supplies very little water stream and is fairly constant once the t'stat opens. The relief assembly does what it says. At higher than idle RPM, it relieves excess pressure supplied from the pump that cannot pass through the t'stats. All you do in connecting to the t'stat is neutralize the stream that should go to the tale-tale.
For the correct connections of hoses: Facing the rear of the motor, the left t'stat will have two hose connections via a tee or inline fitting. One hose runs to the starboard t'stat connection and the other to the lower part of the power head at the rear. The tale-tale connects off the same hose via an inline tee just before the hose enters the power head at the center rear. The "only other hose" completing the water loop is the relief hose coming off the top under the flywheel cover and to the relief assembly.
Now for the tale-tale check. After you get everything connected back, install the ears and hose (with pressure). Remove both t'stats if already installed and start the motor...let run at idle. Observe the water pressure flowing from both openings. The starboard side will almost always have a little less pressure. You should see a good hard stream of water coming from both openings. If you see little or no flow from either side, then you know what to check next. I'm sure you have or are going to replace the t'stats to eliminate them as a potential source of low tale-tale flow.
If you have a good flow from the test, then there is potentially not a problem. Do this in leu of pulling the lower unit first.
If you need numbers for your poppet assembly, advise and I can provide them.

 

[fishingdan]

Re: 1982 150 poppet valve questions

Very good. I'm feeling better now. I understand that the volume of water out of the e tell-tale and the poppet water connection have little do with each other. This is all a result of poking around and finding problem B while fixing problem A.

I double checked the waterpump install last weekend and that looks good. I'll rule that out for the moment (to be validated with testing later).

I will assume that my cooling hoses are routed correctly at this time with the exception of the hose to the relief valve.

I will order the gaskets for the relief valve cover (part number 27-78690002 I believe) and the fitting for the relief valve cover (22-92007 1 I believe). Ncfish, can you confirm these numbers?

I don't think I will touch anything else in the poppet assembly at this time. They look good (probably due to never being used).

Once I get the relief vavle assembly and covers back on the engine, I will remove the t-stats (they are new) and test the flow. If there is no good flow, I will drop the lower unit and test from down below.

Once I see where I am at with the above, I will tackle the relief valve water supply. I'm not looking forward to trying to get that plug out. Maybe I will get lucky.

Thanks again guys. I will keep you posted on the outcome. I would not be surprised to find a bunch of crap inside the engine cooling system or maybe just the hoses.