1982 Mercury 40hp (Part 3) Powerhead Removal, Disassembly, and Reed Valve Replacement

[@carbs66]

Thank you… Finally someone with a video that shows where the reed valves are on a Merc!!!

[@TheAfterWorkGarage]

Thanks, and yes, it's quite a surprise when you take the carb off and there's nothing but crank case.

[@greauxpete]

Just took mine apart. Stripped the Phillips head on the reed cage screw. Had to drill the head out. Sealed the case with master gasket and got it back together.

[@uhoh71]

I commend you for taking on such a project. Got to love them Mercuries!

[@TheAfterWorkGarage]

Thanks. Yes, at the very least they have a lot of character haha.

[@stevehellin7730]

Just found your channel and now I understand how the reed valves work on these mercs thank you for showing this

[@LivetofishOutboardRepair]

Excellent commentary while demonstrating this disassembly. I would suggest not giving advice on flipping reed valves as a solution. Most service manuals suggest not flipping them over as this can cause them to fail quickly and break off resulting in engine failure. Just my 2 cents. Great video! Keep them coming.

[@TheAfterWorkGarage]

Thank you for the kind words, and the good point about the reed valves. I agree I would NOT recommend flipping them over (especially with stainless steel reeds). I was trying to decide if there was a preferred side to install the new ones, and figured it was ok either way since people do flip them. But, you make a really good point that it's not a good idea.

[@uhoh71]

My brother rebuilt a 1974 15 hp Evinrude and one of the reed valves broke off less than a week after getting it going and destroyed a brand new piston. Figured it was due to a substantial increase in compression and old brittle reed valves. Was an expensive lesson.

[@LivetofishOutboardRepair]

@@uhoh71 thank you for sharing that story. I’m sorry to hear it.

[@TheAfterWorkGarage]

@@uhoh71 That is really unfortunate, but these things happen. One big killer of stainless reed valves (other than age and wear) is corrosion. Even though they're stainless, if they sit with any moisture (especially salty moisture), they tend to corrode and develop weak spots.

[@TheMifftown50]

Thanks for putting this together. This is a great video! I have the same Mercury (420) with a jet drive lower unit. I bought the whole thing used a few months back. I have a 13' (~800lb) boat and it won't push it more than 5kts. I think something is wrong. Here are some things that I tried and they did not fix it: 1) I adjusted the height and trim of the engine because I thought too much air might be getting into the jetdrive. No change. 2) I pulled each spark plug to see if it was running on 1 cylinder. Each spark plug was firing and the engine kept running. No change. 3) I pulled the impeller and sharpened the blades. I also verified the shaft key was in place. No Change The boat goes 5kts at 50% and the same speed at WOT with no change. The only change is that the engine gets loud (to a normal level) at WOT and seems to be at full RPM. No tachometer to actually measure. I suspect that something is slipping in the driveshaft. Maybe where it connects into the crankshaft? Since you had the head unit apart on this engine, do you think that is a possibility? If not, any ideas on what it could be? I'm stuck and could really use some help. Thanks!

[@TheAfterWorkGarage]

To me it doesn't look like there's a place for things to easily slip without enough damage that you would really know. Do you have the ability to raise the motor up without trim (like a jack plate)? It seems counter intuitive, but jet drives actually need to expel water ABOVE the waterline to be effective, but trimming it isn't great since you're effectively pointing the intake backwards. Let me know if you figure it out, I'm curious what the issue is.

[@TheMifftown50]

@@TheAfterWorkGarage - Thanks for the reply. I actually already built a custom jack plate to get the jet foot mounted at the corrected height. (front of jet level w/bottom of boat) This didn't work for. I'm in the process of rebuilding a few components and will let you know if I get it figured out. Your videos are great and really helpful. Thanks!

[@crashtestdummie67]

Slipping propeller?

[@lodollar23]

I'd really like to see more of this style engine. Especially the 4cyl ones! I've heard people say the 4cyl was the best engine made

[@omarattard5360]

Are you going to post part 4 of this video would help a lot thanks!

[@crashtestdummie67]

Part 4? I have had my Mercury apart many times now and was about to finally test it on the water. The reeds are bad and now it needs to go apart again...

[@jamesclausen6239]

I am also waiting for part 4 - since part three was posted Dec 7, 2020, am I waiting in vain?

[@TheAfterWorkGarage]

Part 4 posted - sorry for the long wait everyone!

[@m4chschnell]

Would it have been possible to just turn the old reed valves around so they now hold shut rather than open ? . Top video sir . learning heaps for my old merc brown band 35 horse power . almost identical so far

[@TheAfterWorkGarage]

I'm by no means an expert, but I would think the answer is yes, with caveats. If they are super bad, then even backwards they won't seal correctly. In addition, it's generally recommended to get new reeds, since turning them around increases the risk that they will break off, which is bad for obvious reasons. As long as you're going through the trouble of opening the whole motor up, I'd recommend just getting a new set.

[@greauxpete]

Not reccomended, fatigue failure of the reeds could grenade the motor. C Epoxy or carbon fiber reeds are preferred if available for a safety factor.

[@dustinbrunson9262]

Glad you made this video I got same problem with a 35 I'm jacking with. Kept jacking with the carb and needles seat adjustment thinking the carb was leaking finally realizing its the reeds causing the leak smh.

[@TheAfterWorkGarage]

Glad it helped, and I'm sorry you're having that problem!

[@Lukkmaestro]

So this engine does not have oil in like for example a lawnmower would? Is it purely water cooled and lubed up from the mixed gas?

[@TheAfterWorkGarage]

That's correct, the oil that you put in the gas doesn't vaporize as readily, and sticks to the bearings (hopefully). This is the way most smaller 2-strokes function. Larger 2-stroke diesels often have oil systems like a 4-stroke (as well as exhaust valves), but those also must be forced induction, and wouldn't work for small 2-strokes where point is simplicity, power, and cost effectiveness.

[@TimsWorkshopTJY]

good job on that one. My Merc 60hp 1996 has the reed valves behind the carbs so would be real easy to replace if needed

[@TheAfterWorkGarage]

Thank you! I'm assuming at some point they came to their senses. My 2007 Optimax also has them in a more accessible location.

[@benmitchell2642]

How / where would I wire a kill switch for this exact motor? Which wires?

[@benmitchell2642]

For anyone wondering i found out it’s the black wire with a yellow stripe

[@TheAfterWorkGarage]

Awesome thank you so much for sharing! Yes there are some pretty good Mercury wire color diagrams out there. Maxrules.com has a PDF that has a good one which can be found at the stupidly long link below: www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=8&ved=2ahUKEwiC9uyajs_wAhUHHc0KHf8vC_AQFjABegQIAxAD&url=https%3A%2F%2Fmicroplus503.weebly.com%2Fuploads%2F2%2F1%2F9%2F8%2F21983352%2Fwww.maxrules.com_fixmercwiringcodes.html.pdf&usg=AOvVaw0AChwP6SdpfN6BIu2BIkB-

[@TheAfterWorkGarage]

Thanks for sharing your findings!

[@boblee2550]

Thanks for the flywheel removal tips. I have a 1986 35HP the design is identical. I also tried to pull the hub to no avail as I am trying to replace the stator. I was smart enough to mark the flywheel position. Do you happen to know the torque spec for the flywheel nut???

[@TheAfterWorkGarage]

Glad you were smarter than me! I actually figured out that the keyway in the crankshaft faces towards a particular bolt hole on the flywheel (from looking back at old videos), so I think I'll be ok. I don't know the torque spec of the top of my head, but I'll try to remember to include it once I get the flywheel back on/and next time I'm in KC. I hope you're motor repair is going smoothly - these motors seem like a challenge.

[@LivetofishOutboardRepair]

I’m curious as to how you plan on getting the timing right since you removed the flywheel without using a puller. Are there markings on the flywheel?

[@TheAfterWorkGarage]

Good catch there. This is a super good question, and one that I thought about immediately after I removed the flywheel. I definitely should have marked the crank/flywheel position. My plan is to look back at the video and see if I can determine which way it was oriented based on the cut grain of the crank end. Failing that there's two magnets 180 degrees apart, and I'll look into the manual and align them with the crank/stator when I put it back together. Whatever I end up doing, I'll make sure I show it in part 4.

[@LivetofishOutboardRepair]

@@TheAfterWorkGarage I made the same move and since I had two marks on the flywheel being one vertical line (I) and two vertical dots (:) I ended up finding TDC on cylinder 1 and positioned the (I) as close to the pointer on the pull cord bracket. I did get spark as shown in the my video but I guess I’ll see if that worked when I finally get it running. Good luck and can’t wait to see how you resolve this.

[@bluewater1945]

@@LivetofishOutboardRepair just made same mistake. I needed to replace stator and pulled off flywheel with out marking it. Should I be able to find TDC of #1 piston and line up flywheel 0 degree to the arrow on motor? I should receive new stator in a few days. Thanks

[@LivetofishOutboardRepair]

@@bluewater1945 that’s pretty much what I did and the motor is idling just fine. The timing is supposed to be 5 - 7 degrees advanced (:) and the Max Spark is supposed to be 27 degrees (I). The only markings on the flywheel are (:) and (I) marked in white. Since I do not have any other markings and only the pointer window on the pull starter, I believe this is as close as I can get it. You will have the same issue. My feeling is if it starts and idles properly then it must be set correctly. I’m not an expert so I’m not completely sure about this advice.

[@quickturn66]

I’m pretty sure all the fasteners are English, they are on all my 60s and 70s mercury motors. Some people get confused because 11 mm is almost exactly 7/16 as is 14 mm and 9/16 ,1/2 inch converts to 12 . 7 mm.

[@TheAfterWorkGarage]

Yes! you are correct. They are imperial - I know I was using metric sockets in the video (bad), but I'll get the standard set out for putting it back together.

[@adanz15]

Gracias! Estuve usando métrico y se me hacía raro

[@francisbe3898]

Do you think there is any chance to remove the crankcase cover without taking the block out? I have a Merc 500 for the early 70s. The reed valves are a different style but it'S the same idea. There might be more room in a Merc500 so I don't have to remove the block. Maybe I'm just dreaming!

[@TheAfterWorkGarage]

Hi! I'm not an actual Merc mechanic, but don't think you'd be able to do this repair without removing the powerhead. Some of the bolts are a tight enough squeeze as it is, even with it on the bench. Good luck, and if you do manage, let me know!

[@davekimbler2308]

I’m glad you corrected yourself and said REED VALVES and stopped saying POPIT VALVES Martins are the only outboard that has them ! Lmao. Mercury was alway trying different things ! Well you got there but took the long way around the barn , as my grandpa would say ! Lol

[@TheAfterWorkGarage]

Yeah words are hard sometimes haha. While I didn't show it in this video, this engine does need a new thermostat and poppet valve, which I had ordered and my have had on my mind while speaking.

[@davekimbler2308]

@@TheAfterWorkGarage I’m not aware of a popet valve on a Mercury and to my knowledge Martin’s were the only ones with them but I may be wrong I don’t work on Mercs ! Lol

[@davekimbler2308]

@@TheAfterWorkGarage well I’d be tickled pink , I looked it up and dang if it don’t have a poppet valve ! I’m sorry ! I learned something new today ! Lol

[@malcolmrollason]

Fantastic watch .Have the same engine.Been super helpful .

[@TheAfterWorkGarage]

Thanks! I'm glad it has been helpful. Good luck with yours, I hope it's not as much of a pain as this one has been!

[@pjimmbojimmbo1990]

The Older mercs had the Reeds buried deep inside engine on the Bearing Block. This permitted a smaller crankcase Volume for better Crankcase Compression and better transfer of the Air-Fuel charge to the Cylinder. It also made for easier Sharing of a Carb between 2 cylinders, and for a Shorter Engine as there was no External Intake Manifold. It did make it more complicated to replace a Broken Reed, as the engine has to be taken a apart. However, when a Reed breaks, being the Stainless Steel it is, often does serious internally, so having to take the engine apart is a Good way to Inspect for Damage. That 40 hp is basically 1/3 of the inline 6 90hp merc, with slightly different Porting. In 81 it would have been pretty much 1/3 of the 1981 115, but in 82, Merc started Prop Rating the Inline 6s. Even though the 40 is exactly 1/2 of the 80hp of the same yr, there are significant differences in the Pistons and Transfer Passages between the 2. Same for the 82 115

[@TheAfterWorkGarage]

This is great info, thank you so much!

[@officialWWM]

It’s still a stupid design!

[@pjimmbojimmbo1990]

@@officialWWM Why would you say that? It is actually very good Engineering

[@officialWWM]

@@pjimmbojimmbo1990 because you need to completely strip down the whole engine just to replace the reeds, a part that wears way faster than anything else inside the block!

[@pjimmbojimmbo1990]

@@officialWWM Rarely do these Reeds fail, and I mean very Rarely, and if one does Break, the Engine would have to be taken apart to access the Damage the very Hard Steel Reed could do to the Internals. One good thing, is that the design keeps Owners from trying to install those Wear-out very fast Fiberglass Reeds

[@bluewater1945]

Have you found a flywheel puller? I need to change the trigger. Thanks

[@TheMifftown50]

Most auto parts store have flywheel pullers they will let you borrow for free. I got one from O’reilly’s in Seattle.

[@bluewater1945]

@@TheMifftown50 I picked one up at harbor freight today $15.99. Took flywheel off with no problems. Thanks Jeffrey

[@danokeefe4707]

Hi I have the same motor with same problem gas coming out the front of carb. Can you post parts you replaced and were you found them? I’m going to try and tackle the same job. Thanks

[@gregsmith7074]

Hey buddy, maybe you could help me how do I get the rod off that goes down through the shaft to the shifter?

[@LiketoOrganize]

Hello, can you please provide the torque specifications when re-assemblying? (Pistons, Crankcase Bolts, Cylinder Head Cover, Exhaust Manifold, Drive Housing Cover). Thank you!

[@officialWWM]

I have the 50 hp version of this engine and I’m about to go through this pain. I’m trying to decide if it’s worth it or not. Maybe it’s time to just upgrade it…

[@TheBeefSlayer]

I have this old engine on my 1979 bass tracker. This makes me want to sell it and upgrade before it quits on me!!!!!! Thanks!!!!!

[@TheBeefSlayer]

And thanks for all the info and look at the guts!!!! Now I know what to expect and what all I’m looking at when I got to fix a few small issues I have!!!! This info is priceless!

[@TheAfterWorkGarage]

Really glad it helps! Honestly these old 2 strokes will run forever, it just seems like this one takes a lot of work to give it the love it needs. I just made it back up to my shop in KC last weekend and got the block back together and back on the leg, and it's not a huge job, but everything with working on this motor seems to be inconvenient. At the end of the day it's just a fishing tool if it's attached to your bass tracker, and I am mightily impressed that you've kept your 1979 Bass Tracker in good shape all these years. Those old trackers are really cool, but also notorious for having rivet issues.

[@TheBeefSlayer]

@@TheAfterWorkGarage it doesn’t leak at all. Someone did a lot of work on the transom before I got ahold of it. It’s a heavy handed fabricated job but it seems to be holding solid. I need to do all the wire and maybe get whole new co troll box and cables. It all looks original. Also the deck needs replaced and carpet but the boat hull is water tight and the engine will push her at almost 30mph. Feels about fast as I’d care to go in this boat.

[@TheAfterWorkGarage]

@@TheBeefSlayer That's wonderful. I fished out of an old 1960's Strahm fiberglass boat before I got my current one, and it was quirky and old, but a great boat to be in. Glad you're still getting it out on the water!

[@d3lta826]

can you make part 4, im almost certain this is the issue i have on a 1987 mercury 60hp 3cyl

[@crashtestdummie67]

I am in the same boat. Thinking of boyesen power reeds and new piston rings in the same go....ONE HELL OF A JOB ONCE AGAIN...

[@d3lta826]

@@crashtestdummie67 2 months later , it wasn’t the reeds, or anything else , I fully rebuilt it and it’s still not right

[@crashtestdummie67]

@@d3lta826 WTF? What are the symptoms?

[@crashtestdummie67]

@@d3lta826 it was the float on the upper carb. They were made of foam and changed to plastic. Runs good now.

[@simontorgersen2589]

Hi, great video, and I am looking forward to se the rest. I have the same motor, just bouth it, and hoping to get it ready for summer 2021. Mine is running great, but I have a cooling problem. The impeller etc. is new. The water does not come through system. You also mentioned a problem with the cooling. Will you look inn to that in part 4? Happy new year, Simon, Norway

[@TheAfterWorkGarage]

Hi! Thanks for the kinds words. Yes I have looked into the cooling issue, and it was a stuck shut poppet and thermostat. I have shot some of the rest of the assembly, but between the holidays and real life job things I haven't quite gotten it all back together yet. I will try to get the rest of the videos out as soon as I can. Happy New Year!

[@OTFiddlerVT]

I'm trying to deal with a rough idle and stalling problem on my 82 Merc 40. It's really bad news that you have to disassemble the motor right down to the block to replace the reed valves! These motors have SAE bolts/nuts. Why are you using Metric tools? I've found that metric "equivalent" sizes either don't fit at all or are too big, with too much play between the tool and the fastener, potentially damaging the fasteners.

[@TheAfterWorkGarage]

Yeah it's not great. And you're totally right. I should be using an SAE. Most fasteners on motors today are metric, so I have embarrassingly little in the way of SAE sockets. With rusted or painted over fasteners it can be hard to tell when just starting with what seems to fit. I did switch over to standard sockets with this motor eventually once I stopped being lazy (and hunted down some sockets).

[@TheAfterWorkGarage]

Also great to see another fiddler in the comments!

[@lel7788]

I ve exactly the same without electric start, but I can't find the manual or any spare parts :'(

[@TheAfterWorkGarage]

You might have to do a little digging to find a manual, but spare parts are around on various websites. Unfortunately I didn't find one that has all the parts, but searched around online a bit and tried to match them the best I could - and yes, I did order a few parts that didn't fit (but not many). Food luck with your motor!

[@lel7788]

@@TheAfterWorkGarage ty dude, and thanks for videos, it helped me 😁

[@alwice79]

Great video as usual but I was surprised you didnt have the merc flywheel pull tool which threads into the center and has the jack bolt, easy, fast and all off as a unit. $25 canadian on Amazon

[@watcherwatchmen7785]

What manual did you use for this? I'm searching online but have had no luck finding the specific manual for the 402. I'm figuring I'm going to have to buy it, but I'd appreciate a book name or ISBN to search for the right material. Thanks!

[@1luxuryliner440]

Where did you order the reeds valves from

[@andytran2931]

Part 4 coming soon ?

[@TheAfterWorkGarage]

I'm sorry it's been so long, I moved to Dallas for a job, and my shop is still in KC. My plan is to get up there on the occasional weekend to do more work and filming until I can find somewhere to move things down here. So yes, it's coming - It just may be a little bit yet. Thanks for hanging in there while I sort things out!

[@rdeanlive]

Hello great videos.I have a question regarding a 1973 - 1977 Mercury 402 elect Serial no. 7007249.I'm missing the cut out switch or kill switch # 84-63086A2. Replaced switch box all new CDI parts and coils.No one sells this kill stop switch any more would like it to still have kill stop from the ign key. How can I make this work as there is one orange wire to switch box from stop kill switch.Don't want to short $ 375.00 switch box.Any info on this would be appreciated thank you.

[@TheAfterWorkGarage]

Hi! I can't speak for your motor in particular, but I can say that kill switches on outboards ground the ignition system, so in general you're not going to damage it by shorting it out (since it actually is a short to ground). Below is a link to a video about kill switches by Dangar Marine that may be helpful. you should be able to make/wire up your own without too much trouble, but it may take a little wire tracing if you don't have a wiring diagram. kzbin.info/www/bejne/iX-UaJx4gZqfptU

[@thesleep6408]

When we gonna see it running again?

[@TheAfterWorkGarage]

Hopefully in a month or two. I am planning on trying to make a trip back to Kansas City just to get this motor back together and film it, but I am also in the process of looking for a shop space in Dallas so I can get the channel back and going again! Sorry for the long ambiguous answer, but life happens some times, and I still really want to get making videos again!

[@stevehellin7730]

Mine is a 6 tower 1350 and i am rebuilding it and am searching for all info i can find so again thank you

[@avenaivucago1713]

Very interesting marvelous job

[@travelguy1564]

Hi - what model years did Mercury put the reed valves like this? And for what horse power engines? Thanks!

[@tylerjohn975]

Where did u get the reeds

[@iketurner3169]

Where's part 4.....having trouble with timing on this motor.

[@TheAfterWorkGarage]

I'm hoping to get it out relatively soon. I moved, and my shop is still in Kansas City. Until then I've had videos kind of on hold until I can get up there and finish filming. I'm also looking for a shop space in Dallas, since I want to get making videos again!

[@adanz15]

Buen canal y video, te saludo desde colombia tenemos un mercury igual pero sin arranque electrico de 1989 pero desarmando esta en muy malas condiciones todo el motor por dentro esta oxidado y de repuestos no creo que consiga nada, gracias por compartir información y videos que en mi idioma no encontraría 😊 excelentes video y muy técnico a la hora de trabajar Saludos

[@alwice79]

Oh forgot to mention, mine an83 50hp 4cyl.

[@hopdjandy]

You Didier need to rip engine apart to change Reed valves survey there on separate bit just behind the carbs

[@TheAfterWorkGarage]

Unfortunately the reed valves are indeed surrounding the crank in this motor, necessitating the partial tear down to access. I agree however that most of the ones I've seen have the reed valves just behind the carb.

[@Scott-ec4ux]

WHERES PART 4 ??? ______________________________

[@TheAfterWorkGarage]

It's in the works. I've actually shot some of it, but I moved do Dallas for a job, and my shop is still in Kansas City. So until I move things down here, I'm limited to working on the odd weekends that I can make it up there. I know that's annoying, but I'm working on solutions (that I can afford lol). Thanks for your patience!

[@thomasbudiselich7746]

Thank you so much I have the exact same motor and looking forward to your reassemble video. My motor was not pumping water replace the impeller and was getting water out of the brass port on the cylinder cover but minimal water out of the Telltale. I also noticed water around the spark plugs when I blew air through the water passages I'm assuming the gasket is not sealing around the cylinder head cover. I would like to suggest and see in your video you may want to pull the spark plug cylinder head cover and check for blockages and replace that gasket. Also the side plate connected to the hose on the side of the motor up to to the fuel pump. I am determined I have a blockage between the fuel water inlet and the bottom of the motor side plate. Would be much easier to disassemble and check this with the power head on the bench.

[@thomasbudiselich7746]

While you're making your video could you show this check another gentleman I was trying to explain , check the gasket on the exhaust transfer plate, the plate behind the linkage(left side). there are 2 gaskets there that allow the exhaust/ water to mix if bad. Water pump pieces like to get trapped there also. Appreciate your video very very much I live 3 hours north of Kansas City Missouri

[@TheAfterWorkGarage]

@@thomasbudiselich7746 Oh that's awesome! I actually recently moved down to Dallas for a job, so my shop is still up in KC, and I'm working to get a place down here that I can move my stuff to. Yes there's definitely a thin water passage on the exhaust side that things like to get stuck in. I didn't mess with it in this video, since I didn't want to risk having to buy another gasket if I didn't need to access that area, but when I (finally) get a change to get this back together, I'll point out where it is. Thanks for the comment!

[@TheAfterWorkGarage]

@@thomasbudiselich7746 Yes, thank you for your info! It is much easier to disassemble on the bench, but honestly this has not been the most fun motor to work on. I feel like everything is in an inconvenient spot, and there's lots of fiddly things that take a lot of time and patience to say, work a bolt on with a wrench 1/8th turn at at time. Cooling passages on older motors love to get blocked up, especially when an impeller shreds, or they get run through sand and mud.

[@grantscime5708]

Where did you find the parts for this engine I have the same engine I can’t find a fuel pump

[@TheAfterWorkGarage]

Hi! Sorry for the slow reply. I got this particular kit here: www.marineengine.com/newparts/part_details.php?pnum=MER21-13424A+1 I have also seen a similar kit on Amazon which may work as well: www.amazon.com/Mercury-Mercruiser-Quicksilver-21-8M0084276-Check/dp/B003900KH6 Hope this helps!