How To Replace the Poppet Valve on a MERCURY 135 BLACKMAX Engine

[@FKCamVlogs]

Nice Video with good details, it would be helpful if you had part numbers listed in description. Never the less, great video !

[@ProWrenching]

Thanks for the suggestion. Ok- parts now listed in description. Purchased on boats.net. Here you go: 144791 - DIAPHRAGM 14480 - POPPET 16496 - DEFLECTOR 64872 - GROMMET @2 64878 - SPRING 65848 - CARRIER 69570 - SCREW 74824 - SCREW @5 76451 - WASHER @2 78690002 - GASKET @2 - Replacement part for 12-78690 85303 - WASHER

[@nathanvincent1285]

Taking the bottom cowl off makes this a whole lot easier. Just an FYI. A couple screws and you’re good to go

[@biodot88]

The most important aspect is if the spring and grommet and seal in that assembly is hung up in any way, or if you forget a seal in the spring assembly, your poppet will be stuck open. You will have a weak P stream, and you will have alarms and guardian mode. Parts 11 through 17 in the BOM are important. Google the Mercury parts catalog and look up the exploded parts view for your engine. This will tell you how to assemble and show you the proper orientation of the various piece's. Be especially careful with the grommet which fits inside the carrier. Do not fold or pinch the edge of the grommet seal or it will leak = alarms. Newer engines do not have/use the white washer.

[@frrodriguez9423]

I change mine recently and leaks : (

[@dalebechtel8904]

Thanks for the video. I need to do mine soon. 👍

[@jedzeplin9431]

way easier with the lower cowl removed.

[@vi23100]

@11:00 The main reason the poppet valve starts to bind causing overheating problems at high rpms is that grommet Corrosion starts to build up around the area where the grommet sits causing the circumference of that grommet to get smaller and thats what causes the bind of the valve I noticed you didnt clean out that corrosion.

[@horacelee880]

Sir this is an EXCELLENT video and because of your work I now feel confident that I can change out the poppet valve on my 89 Blk Max 150 engine! One question : What make of cordless wrench are you using to remove those 1/2 bolts on the poppet valve? I`d love to get my hands on one of those

[@ProWrenching]

Thank you- I appreciate that!! It’s a 3/8 drive Milwaukee.

[@SolarBurrito]

I had one 1/2" bolt that was so tight I think I'll break it if I put that much force on it. How much force did you have to apply to a 3/8" rachet?

[@ProWrenching]

@@SolarBurrito mine was normal, not that tight.

[@walkertonheights]

When you are disassembly , I seen the very large silver washer behind the diaphragm (merc 16496) was stuck in there pretty good. Do you think that is why your poppet valve was failed?

[@ProWrenching]

@@walkertonheights The poppet valve didn’t fail on me, luckily. I was doing preventative maintenance b/c the engine is 30 years old. Thanks for watching the video- I appreciate your comment!

[@billallen1095]

I appreciate this well done video. I have looked at several and this is the best. I have one question. At approximately 14:45 in the video, you show a part #65848 (Carrier) . You look at the package and then set it aside. I don't see what you do with it. I have the same part and I can't figure out where it goes. Any suggestions? Thanks!

[@ProWrenching]

@@billallen1095 Thank you! Glad the video was helpful. I ordered all the parts for the job, but after I inspected the existing carrier, I decided that was in good condition and decided not to replace it. The carrier is a plastic ring that sits inside the block.

[@alexanderaskew-st2re]

Where did you put the Carrier piece? I didn't see you place it anywhere and my kit also came with one.

[@ProWrenching]

I bought a carrier but didnt end up replacing it b/c that wasnt broken and my thought process was if it ain’t broke, no need to fix

[@brentl7437]

Thanks for this video. Helped me a lot. It was a pain to get it back in and get the bolts in. Question: on the very outside metal cover directly over the poppet valve, there is a small hole at the bottom. When I start my motor, water is coming out of that hole. I'm pretty sure that's not supposed to be happening? Any idea why that would be happening? I replaced everything inside, same as you did. Thanks in advance for any help.

[@ProWrenching]

If you’re talking about the small hole in the bottom of the plate covering the poppet valve assembly, it should not be leaking water from there. I would make sure that you have your outer bolts torqued correctly - should be 150 inch lbs. Perhaps they were too loose and allowed water to leak past the gaskets? if the bolts are tight, you may have to disassemble and inspect gaskets and parts for defects.

[@biodot88]

Your poppet is stuck open. Disassemble and check your grommet and spring etc

[@stewpeterson3331]

Greetings again PW! -- Pulled my poppet valve and doing the rebuild. Did you ever find a function for the thick black washer/ring you are holding at 14:44? I have the same piece and not sure where it's needed. Thanks, Stew

[@ProWrenching]

Hi Stew- that ring is the carrier. I ordered all the parts for the job, but after I inspected the existing carrier, I decided that was in good condition and decided not to replace it. The carrier sits inside the engine block.

[@mikesvaporie8781]

Hi great video!! I have same motor just a 225hp. My poppet valve is leaking at higher rpm. Do you know is there a way to tell if it the valve bad or something else? Someone said typically if it was something else it a blockage in exhaust but highly unlikely. Any suggestions? Thanks

[@ProWrenching]

On my boat, I installed new thermostats, changed the poppet valve, and also found an obstruction in the hole for the telltale stream. Also put in a new water pump impeller. I have videos demonstrating all those things. I would recommend doing all those things if you dont know the maintenance history of the motor.

[@mikesvaporie8781]

@@ProWrenching thanks

[@ParsonsAAA]

How tight or loose do you want that spring to be when replacing it? Because you can have a lot of play or not much at all. Removed mine a few days ago and I don’t remember how tight the old one was.

[@ProWrenching]

Since it was a 30 yr old part, I decided to replace the spring to be on the safe side.

[@ParsonsAAA]

How tight are you tightening the screw into the valve itself ? All the way right?

[@ProWrenching]

@@ParsonsAAA yes- all the way. Tightening regular hand tight

[@ParsonsAAA]

Thanks a lot!

[@majorbrown6817]

Excellent video I have been searching for this for some time now. I have a 92 Merc XR6 that I will be doing the same. How did you ID all the part numbers? And was this preventative maintenance or was there an over heating problem? Did you notice a stronger pee stream after replacement ? Thanks so much.

[@ProWrenching]

Thanks! Marineengine.com has a good breakdown on parts. This was preventative maintenance. No problem with the engine overheating. The telltale stream seemed weaker than it should be, though. I did the poppet valve and also installed new thermostats during the process. I also inspected the telltale hose and found a small shell in the hose that was causing the stream to be weaker. I have a video showing that coming out later.

[@scottmccoy4129]

Great Videos- I learn something every time. Where do you like to buy your OEM Quicksilver parts? I’m looking for a cost effective & reliable source…

[@ProWrenching]

Thanks! I bought the parts used on this video from boats.net. Marineengine.com or Amazon are other places I buy boat parts, depending on the project.

[@dthompson5406]

I have a question, the screw that goes into the back of the actual plug with the spring, does that screw actually screw all the way in? Mine only went probably half way before it got really tight?

[@ProWrenching]

Yes- it screwed all the way in

[@dthompson5406]

@@ProWrenching thanks for letting me know

[@hokemims8275]

Noticed you had a carrier grommet, where does that go

[@ProWrenching]

It goes in the block. I didn’t change mine b/c it was in good shape.

[@outdoorswithjv1616]

Hi I’m doing this fix my self I have a question the carrier it’s hard to take it out I didn’t see you replace it in your video is that inside where the grommet is at?

[@ProWrenching]

Yes- it’s in the block. I bought the part for the carrier, but didn’t replace it b/c it was still in good condition and I thought if it ain’t broke, no need to fix

[@outdoorswithjv1616]

@@ProWrenching ok thank you for replying!!

[@outdoorswithjv1616]

I have another questions you might be able to answer. So I took mine apart and it all looks like new and I’m like you I bought this motor used so I don’t know no history of it. How do you know when it’s time to replace them?

[@ProWrenching]

@@outdoorswithjv1616 for the carrier- just compare to the new part to see if there are any obvious differences, sizes, wear, etc.

[@jimhazlehurst1150]

What keeps the rubber grommet in place when you slide in the poppet valve? Don't want to push it into the cavity?

[@josemariatrueba4568]

What's the reason to replace sll parts? The only thing that may be degraded would be the diaphragm. Poppet valve may be clogged closed with rust and deposits which I think is my case as engine temperature is alright beliw 1500rpm but if I jump to 3000 rpm temperature needle goes to 3/4 in a couple of minutes when alarm starts sounding. Going back to 1500 rpm cools the engine stopiing from sounding the alarm quickly. soon showing less than 1/2 at temperature gauge in the next coulple of minutes. Looks like valve doesn't move when water pressure gets high enough as rpm increases from 700 at idling to 1500 twice as much or 3000 rpm 4 times higher than 750rpm. I believe that my poppet doesn't move. Cleaning and replacing gaskets should be enough, but I do understand that replacing everything might be advisable. I've read that thermostats regulate temperature below 1500rpm while poppet should be closed, and poppet regulates temperature by starting opening above 1500rpm.

[@ProWrenching]

The reason I replaced all the parts was due to my time constraints. I ordered all the parts before tear down & inspection of the poppet valve b/c these parts can take a while to come in and I didnt want to have my boat out of service for a long time awaiting parts. There could be multiple factors that cause an engine to overheat, a couple of which you mentioned above. Sounds like you might need to take apart the poppet valve and inspect. --- maybe other viewers who are experts on flow issues will chime in on the discussion.

[@josemariatrueba4568]

@@ProWrenching Understood! Yes, first thing is to get the gaskets and then remove poppet valve to clean everything and be sure that valve moves freely before tightening the four screws..

[@vi23100]

The poppet is there to open after around 2k rpm to allow better cooling at higher rpms The KEY here is removing the grommet, and cleaning out the corrosion that builds up around the grommet! This corrosion pushes against the grommet all around making the circumference of the grommet smaller and that's where your valve starts to bind Must clean out that salt and corrosion on the grommet seat. Otherwise, your efforts are futile.

[@josemariatrueba4568]

@@vi23100 Mercury manuals say that poppet should start opening at 1500rpm, when water pressure is strong enough to push the diaphragm which is resting against the spring load which closes the grommet. Let's consider four stages, idling at 750rpm when water pressure is smallest, 1500rpm when water pressure is high enough to climb all the way to the top because waterpump is runing twice as fast, 3000rpm with waterpump at four times higher speed, and 6000rpm with waterpump at eight times higher speed than at 750rpm. Poppet should be closed between 750 and 1500rpm, allowing the small water pressure running at low rpm, to reach the top of the motor where the thermostats are located. Thermostats starts opening very early as soon as water temperature is 55°C because water first of all goes to the hottest place which is the exhaust manifold. Poppet starts openening at.1500 and will be more and more opened between 1500 and 3000rpm. It should be completely opened from 3000 to 6000 rpm allowing full water flow existing freely, relieved, after having passed through water jackets of the 6 cylinders. If poppet valve doesn't open at the right rpm the water inside the cylinders jackets will stay there and start boiling very-very quickly. If waterflow would remain opened at low rpm, in the most improbable case that the spring is broken, water pressure at low rpm will be released and water will not reach the upper part of the engine. Motor will be overheating at idling at 750rpm and also at any other low rpm below 1500rpm. The waterflow paths, are controlled by the thermostats at low rpm and by this pressostat or pressure switch named poppet or relief valve, above low rpm. The process is clear to me but... Once I understood the process I have replaced the broken diaphragm but my mercury 135 2.0 v6 engine keeps overheating every time we go over 2000rpm. I have to assume that water pressure is strong enough for the membrane to pull hard enough to release the spring. Membrane should be releasing the spring and grommet sould allow the water to exit freely but this will never happen if water pressure is too low because water passages are partially clogged, same as if spring were too stiff. Maybe I should cut the spring in half, or better yet to try to run the engine without the poppet valve installed. How can we clean the grommet so water can exit out there?

[@gerard1212011]

Do you have to wait a few minutes before it start peeing as you wait for the thermostats to open?

[@maxtaul2601]

I have the same motor and it would take a few minutes to start peeing. Replaced my pump impeller and it starts within 20 sec now.

[@josemariatrueba4568]

It shouldn't start peeing until at least one thermostat opens

[@TylerRitter-u9n]

How tight do you screw the screw in on the poppet valve itself not the housing?

[@ProWrenching]

25 inch lb.

[@jeffreydickson4373]

Looks like a 200 will use the same parts as a 135?

[@ProWrenching]

I think so, but to be sure,- you should use your engine's serial number when ordering to make you are getting the correct parts for your engine.

[@jeffreydickson4373]

@@ProWrenching that’s my issue with everything on this engine. All the numbers for anything are gone. I am guessing at the horsepower and the year. 😂😂😂

[@ProWrenching]

@@jeffreydickson4373 well- that does make it challenging! I saw some universal kits on Amazon that say they fit Mercury 135-200 HP engines. Maybe try one of those?

[@jeffreydickson4373]

@@ProWrenching it’s what I ended up doing. It’s been a challenge - should have heard me and West Marine tech trying to figure out a prop! Lol. Long stupid story how I ended up with this engine, but suffice to say that particular mechanic has never had my business again!

[@daddski1]

dude??? Why didn't you just take off the side cover? Three bolts and you have direct access without fighting everything?

[@ProWrenching]

My motor spent some time in the salt in the Tx Gulf, so didnt want to chance breaking any bolts I didnt have to.

[@donaldnorris9165]

Blackmax

[@hunter6099]

👍

[@danielcurtis7902]

Should explain what the poppet valve does 😐

[@Nonplused]

Hey I have that exact same engine! I think they are pretty rare, although it is very similar to the rest of the mercury line from that era. Even the Optimax shares a lot of parts. Question: How hard is it to take the lower cowling off for better access? I have stories about my motor, oh boy. Years ago I spun a bearing and had that rebuilt. Somehow the idiot mechanic that did it managed to get the block back together right, or at least I hope so, but he managed to plumb the hose that is supposed to take water from the top of the engine to the poppet valve directly to the tell-tale, and route the hose that is suppose to go from the thermostat out to the tell tale, no he routed it through the thermal air valve (which is supposed to go to the carburetor) and then to the poppet valve. The hose to the carburetor was left lying at the bottom of the cowling. Not surprisingly, this cause poor cold starting and engine temperature issues (running too cold at low power). Surprisingly the thermal air valve still works despite having water flowing through it for years before I finally figured out what has all wrong, which is good because you can't get those anymore. Maybe used but I only found one and the guy wanted $300 for it. Strangely, this duffus mechanic had to add a hose to get his replumbing masterpiece done, which should have been a sign that maybe he was doing it wrong, whereas I was able to correct it using just the factory hoses. And this was a Mercury dealer! Thankfully they are out of business now. I had another shop replace my steering cable, and the guy managed to crush the transom and put the rack on upside down so the steering was backwards! Thankfully they fixed it for free and fired the guy, but sheesh. How hard is it to do a steering cable? Wouldn't you turn the wheel a bit to make sure the motor was going the right way? Good help is so hard to find. So bottom line is it better to fix these things yourself. They main reason I didn't do the steering cable myself, I tried, but it turns out my motor had to be lifted to get the cable out/in (or cut the boat which I didn't want to do). I didn't have a hoist at the time. So anyway, I was hoping in this video to catch a glimpse of the back of the engine to confirm my plumbing, but I did not. Still a good video though. I think I will rebuild my poppet valve too, just because it is a very important part of the cooling system and it hasn't been done, and it doesn't look like a big job. Easier than replacing the impeller I think.

[@ProWrenching]

I have not needed to remove the lower cowling off my motor yet. I was able to access the bolts to do the poppet valve, fairly easily with the cowling in place. I would agree that if you do your own mechanic work and you take your time, you will often have a higher quality repair than when paying someone else to do it. There are a lot of bad mechanics out there. A lot of shops will just hire anybody who will work cheap, which doesn’t always work out so well!

[@shamansshaman1823]

It's not hard to take it off. Saves having to undo all the electrical you see in his video and makes it much easier to access the poppet valve cover.