Water flow through poppet valve

[Todd98SE]

Hello all,

I have a 88' Mercury V200 with a possible overheat issue that ive been trying to solve the last few months. I've replaced everything water related (sometimes more than once) trying to figure this out. At idle and mid throttle everything is fine, however at WOT the temp gauge creeps up to the "H". I have close about 25psi of pressure at WOT and between 2-4 at idle. Brand new water pump, thermostats, poppet, head gaskets, exhaust chest gaskets, hoses, etc. I've read every thread possible on this subject and still cant see where my problem lies.

My question revolves around water flow through the poppet assembly. I have the typical "figure 8" poppet cover but without any hose coming off the smaller section of the "figure 8". The smaller hole is open, not plugged and if the poppet cover is removed and I start the engine water immediately starts coming out of the small hole, not the larger hole where the poppet valve sits. From looking at the plates and gaskets that make up the poppet I have a hard time visualizing where water is flowing once the poppet unseats from the block and starts flowing? The logical outlet I see is going through the small hole that the shaft of the poppet valve rides in then across the poppet cover and out the small hole. There doesn't seem to be any other place for the water to exit from once it enters the poppet cavity in the block.

Thank you for any input you might have.

[transomstand]

The fitting on the cover should never be open. A bypass hose from the top of the block should run to it (from the 1/2" pipe fitting hole)

The poppet dumps into this cavity when open. It's easy to "see" the poppet open on the water pressure gauge, at about 1800 rpm the water pressure should drop sharply about 8-10 psi when the valve opens.

http://i221.photobucket.com/albums/dd58/transomstand/Tech%20Stuff/poppet_1.jpg (http://s221.photobucket.com/user/transomstand/media/Tech%20Stuff/poppet_1.jpg.html)

[Todd98SE]

So I just went to take another look and I don't know how I missed the machined section in the poppet cavity that drops down into the adapter plate. I must be getting old or the beer confused my memory of what that area looked like.

regardless, thank you transomstand for adapter plate picture. I'm going to try to use an inspection mirror and see if that cavity is somehow plugged with something that is restricting flow through the poppet. In regards to a fitting and tube running from the small hole on the poppet cover to the top hole on the block should I consider adding one? This motor definitely isn't plumbed that way from the factory.

thank you

[transomstand]

The addition of the hose was a production change (I think in 88) originally to stop the water cooled regulator from overheating by eliminating steam pockets that can develop in the block and divider plate, so it won't hurt.

[Todd98SE]

So if I wanted to make the same change on my older motor I assume I need to plug the small poppet hole with the thimble shaped plug like I've seen on the later motors?

[transomstand]

The later motors all use the bypass hose.

[tlwjkw]

is tha "small hole" a threaded opening or hose bib? does your block have a hose bib on top of tha block that can be connected by hose to tha "small hole" at tha poppet cover? tha '88 shouldn't have either of these....

[Todd98SE]

The small hole has neither. I was going to plug the small hole in the block, machine the poppet cover for a hose bib and change the top feed to a Tee so it can feed the water pressure gauge and the hose down to the poppet.

on the muffs the upper cylinders are noticeably hotter leading me to the conclusion that a bleed off the top of the block would be beneficial.

[tlwjkw]

how "big" is tha small hole?

[Todd98SE]

Maybe 1/4"-3/8". The other pics I've seen of later blocks have that hole plugged with an inverted "thimble" looking plug.

[tlwjkw]

yours shouldn't have tha hose.. it could be a "design I or III" poppet.. probably a I and should work fine just plugged.. but like heathern says it may benefit ta do tha hose thing since merc decided ta keep that bleed hose even after tha water cooled reg. went away.....I have never "looked" at tha two different types plates so don't know if they are tha same or not and sure don't know if they are tha same as tha '89 up that's meant ta be used with tha bleed hose......there may/ may not be some subtle differences in tha plates along with tha "guts".

[Todd98SE]

Now that I think about it with the small hole open feeding water pressure to the back of the poppet valve and pressure on the face of the poppet after coming through the engine is the poppet even opening? I would think equal pressure on the front and back of the valve would keep it closed.

[tlwjkw]

anyway ya cut it that hole is not supposed ta be open....even for a bleed hose with your type poppet.

[Todd98SE]

OK, so today I used a 5/8-11 set screw which fit perfectly in the small poppet hole along with some Permatex Gray to seal it. I re-installed the poppet cover using a spring with 1 coil cut and no white spacer. Fired her up and I had about 12 psi at high idle. Once the 120 degree thermostats opened and the idle settled down I had about 7-9 psi at idle. This is on a new full water pump (new top/bottom base, gaskets, impeller, etc.) which has only about 1-2 hours of run time on it. I haven't tapped the poppet cover for the 90' fitting to run to top of the block yet, i'm not sure if that's needed or not yet. Will adding the feed from the top of the block to the poppet fitting bleed off any additional pressure?

The brand new Teleflex temp gauge (new sender also) read exactly right in the middle of the gauge which corresponded to about 135 degrees at the top of the head and 120 degrees near the bottom of the head using a laser thermometer.

Assuming that all sounds safe i'm going to take the boat out this weekend and hope the water pressure doesn't go over 25psi at WOT.

[transomstand]

OK, so today I used a 5/8-11 set screw which fit perfectly in the small poppet hole along with some Permatex Gray to seal it. I re-installed the poppet cover using a spring with 1 coil cut and no white spacer. Fired her up and I had about 12 psi at high idle. Once the 120 degree thermostats opened and the idle settled down I had about 7-9 psi at idle. This is on a new full water pump (new top/bottom base, gaskets, impeller, etc.) which has only about 1-2 hours of run time on it. I haven't tapped the poppet cover for the 90' fitting to run to top of the block yet, i'm not sure if that's needed or not yet. Will adding the feed from the top of the block to the poppet fitting bleed off any additional pressure?

The brand new Teleflex temp gauge (new sender also) read exactly right in the middle of the gauge which corresponded to about 135 degrees at the top of the head and 120 degrees near the bottom of the head using a laser thermometer.

Assuming that all sounds safe i'm going to take the boat out this weekend and hope the water pressure doesn't go over 25psi at WOT.

This is all wrong. My apologies, I KNEW I should have asked for a photo. This whole conversation was assumed by me that we were speaking in the context of cover on when you were talking cover off.

[Todd98SE]

Now I'm confused. Should I not have it plumbed this way?

[Todd98SE]

With the current plumbing I have "design 2". The original setup was "design 3", and by adding the hose from top of block to poppet cover I'd have "design 1", correct?

[Todd98SE]

In the end I'm just trying to increase flow through the heads to get the motor to run cooler at WOT.

[transomstand]

With the current plumbing I have "design 2". The original setup was "design 3", and by adding the hose from top of block to poppet cover I'd have "design 1", correct?

No, it's not that simple.

[transomstand]

Again my apologies. I thought this might be a quick routine fix when I responded but it may take a good deal of time to get to the bottom of the heating cause. Unfortunately over the next few days I'm buried in an estate sale, moving furniture, meeting with contractors, crying over the loss of my boat workshop, and murdering a neighbor (hopefully without getting caught) so I won't be able to put much time into this for you. Hopefully one of our other "cooling guys" can help you get this squared away.

[Todd98SE]

Thank you very much for your assistance transomstand. I'll remove the plug and run the original configuration on my river trip next week.

[tlwjkw]

you need ta put tha thing back ta completely "stock" parts.. water pump assy., t-stats and poppet assy. if it won't act right, then ya start lookin' for tha problem... not chanhin'/modifin' stuff..........jmo

[Todd98SE]

you need ta put tha thing back ta completely "stock" parts.. water pump assy., t-stats and poppet assy. if it won't act right, then ya start lookin' for tha problem... not chanhin'/modifin' stuff..........jmo

Thats what I started with. Completely stock with all new parts and still had the WOT overheating problem. That's why I started looking for ways to increase flow through the heads.

[tlwjkw]

Completely stock with all new parts and still had the WOT overheating problem. .

is this by gauge or warnin' buzzer?

[Todd98SE]

Brand new gauge and sender. 135 degree head temp is smack dab in the middle of the gauge per my laser thermometer

[tlwjkw]

so what was tha over heat temp?

[Todd98SE]

Not sure. I wasn't able to take a head temp while the temp gauge was pegged out. I can take reading at the "C", 2nd, and middle hash marks and then extrapolate what the temp should be at "H" assuming the sender is linear. The overheat alarm did not go off but I've never heard it so I don't know if it works or not

[tlwjkw]

ya need ta make sure tha over heat sensor is workin'... ya need a sound and/or visiual light 'cause ya might not be "lookin'" at tha gauge often/long enough ta catch it.. never trust a store bought gauge readin' hi "metal" temp as only source.. why tha 120's and not tha 143's?

[Todd98SE]

I suppose I can pull the overheat alarm sensor and heat it up in a pot of water with a good thermometer and see what temp it goes off at.

Im using 120's because I primarily boat in extremely warm water, the lower Colorado during the summer. Water can get to the 80's.

[tlwjkw]

99% of tha time if ya jus ground it at tha term on tha motor with tha key on and buzzer sounds its good.. ta really get down to tha real testing takes an old head and a "rose bud" with temp gun.........

[Todd98SE]

It does sound when I ground out the terminal and it is a new warning alarm. The previous owner had removed the original.

[tlwjkw]

look under tha dash for an "extra" tan/blue wire going nowhere.. it can be used with an LED light to come on with tha buzzer.. take it out without tha cowl off, run tha pizz out of it and check it with tha temp gun (after ya put it back like its all supposed ta be).. you may not have a problem .. jus keep in mind tha motor will not run at a real "even temp" all over.. there will be some differences.

[Todd98SE]

What is the max surface temp that I should be comfortable with? 180?

[tlwjkw]

jus always figured tha buzzer and/or light ain't on so its all good.. max for most folks varies a lot (store bought gauges) from what I've heard and read on production motors.. not many use a temp gun and/or calibrated gauge.. Just run it and see what it settles at wfo.. I don't do much "production" anymore.. I liked 170/180 on short burst on tha hot rods...get some disagreement on it but have yet ta "burn one down"... jus like anything, controlled heat makes horse power..

[Todd98SE]

I'd like to revive this thread and ask a few more questions. I continue to have almost peg out the temp gauge on "H" when I'm full throttle. Water pressure is around 15-20 psi and water is more of a constant spurt rather than a steady stream at high rpm. Idle temp is about 140 at idle which is slightly over the 1/2 way point on the gauge.

ive tried all combinations of thermostats and washers, new water pumps and poppets to no avail. I'd really like to revisit converting to the late model 2.4 water flow using the fitting off the small side of the poppet to the top of the block, if I did this what size fittings/hose (I.D.) are typically used and where would I tap for water pressure? I know I need to plug the small hole leading into the block in the small side of the poppet area when I convert. Should I expect that configuration to increase flow through the top of the heads for more even cooling of the heads from top to bottom?

here are some pics of what I'm working with currently, thank you.

http://i9.photobucket.com/albums/a91/todd98se/218BEF45-ADAF-4EBE-8B37-0D7C25049C3F_zpsifo2adej.jpg (http://s9.photobucket.com/user/todd98se/media/218BEF45-ADAF-4EBE-8B37-0D7C25049C3F_zpsifo2adej.jpg.html)

http://i9.photobucket.com/albums/a91/todd98se/CEEEEA04-7DA3-44DF-99B8-8C8B460E57C2_zpsvn10pbvv.jpg (http://s9.photobucket.com/user/todd98se/media/CEEEEA04-7DA3-44DF-99B8-8C8B460E57C2_zpsvn10pbvv.jpg.html)

http://i9.photobucket.com/albums/a91/todd98se/28D7EAD8-DD31-4959-AF9A-DC4213E29BCE_zpssn6l1vgk.jpg (http://s9.photobucket.com/user/todd98se/media/28D7EAD8-DD31-4959-AF9A-DC4213E29BCE_zpssn6l1vgk.jpg.html)

http://i9.photobucket.com/albums/a91/todd98se/6D9E0E78-18CE-41C4-98AF-B6902BE3E5BB_zpskofwelod.jpg (http://s9.photobucket.com/user/todd98se/media/6D9E0E78-18CE-41C4-98AF-B6902BE3E5BB_zpskofwelod.jpg.html)