Mercury Outboard Side Bowl Back Drag Carburetor - Cleaning and rebuild

[@chetdalton3953]

Im going to attempt this due to a flooding issue im having. I appreciate you putting this together

[@baileyRTRnelson]

Brother I am so excited to see you’ve uploaded videos on this motor. I have the exact model and videos and parts are like finding gold!! Thank you

[@TheAfterWorkGarage]

Really glad it's helpful. Yeah there's so many different styles/models of Mercs (unlike Johnson/Evinrude, Mercury changed their designs often) that it's hard to find a ton an any one model. Good luck with yours!

[@watcherwatchmen7785]

A great cheap dip to clean your carbs is 1/2 pine oil 1/2 water mixture. Put it in a crock pot to heat it up, or use an ultrasonic cleaner. Rinse with hot water and blow dry with compressed air. It's an old timers trick I learned from working on vintage motorcycle carbs in the 1970's honda forums.

[@AndrewMeyers11]

I’ve been pulling my hair out trying to get the choke spring to work and I’ve spent far over an hour. Thank you so much!!!!

[@TheAfterWorkGarage]

So glad it was helpful! I hope you for your motor running!

[@keithlinkous1008]

I spent 6 hrs yesterday trying to find the rebuild kit and this video helped me sooo much. Thanks man!!!

[@TheAfterWorkGarage]

Glad it was helpful! Old boat things can be a little tricky to find, but it's worth it when it all comes together!

[@thercattrainer]

Thanks for posting! Those are Mercury WMK carburetors which were very common on Mercury 2 stroke Outboards which included the 115hp Mercury “Tower of Power” L6 outboard engines! However, there aren’t very many KZbin videos posted about rebuilding them. You can plug off the Back Drag tubes using 1/4” vinyl vacuum hose end caps. Those are tight but they work fine!

[@TheAfterWorkGarage]

Thanks for the info. I definitely like feedback from people who actually know about these motors!

[@thercattrainer]

@@TheAfterWorkGarage YW! There aren’t very many marine engine repair shops that still want to work on any 2 stroke carbureted outboard engines, so a person has to do extra research to find someone who does that type of work, or work on it themselves. I know of a couple of self employed, marine engine, mechanics locally who I can ask, who still do that type of work, but they stay very busy working on all types of marine engines. Yet, most Marina based engine repair shops around here just will not work on those 2 stroke carbureted outboard engines anymore. They no longer even keep those 2 stroke shop manuals in their shops either. Their marine engine mechanics even ask me if they can send me a 2 stroke engine’s “Tower of Power” customer who is having problems with theirs, and I just smile back and chuckled a little bit too! LoL 😂

[@mary0308]

Thanks, I couldn't have cleaned and rebuilt the carb without this video!

[@tim22177]

Thank you for video, I have a 88 35 hp and I was going crazy trying to reinstall chock plate and spring 😭. Your video saved the day 🙌🏼

[@TheAfterWorkGarage]

Glad it was helpful! It's a frustrating design to say the least.

[@chrisbennett5796]

I have a 1978 90hp “Tower of power”. It has the same model of carburetor, but 3 of them. I did the rebuild today, but obviously it took a bit of time. One thing you should always check is the height that the levers are when the needle seats in the float bowl lid. Also, there is a specification for the length of the little spring sticking out of the top of the float. My 1979 manual says it is 2.4 mm. Mine were a bit short, so I stretched them. Yours looked a quite a bit longer than that, but maybe the specs changed later. I do know that the float level is important.

[@bigdummiegarage9022]

Thank you so much for making this video! I just bought a new to me boat and it had the same carb on a 35hp merc. This helped me a lot! Let’s hope she runs!

[@TheAfterWorkGarage]

I'm glad it helped. I hope she runs for you!

[@bigdummiegarage9022]

@@TheAfterWorkGarage so it seems that I don’t have a fuel issue I believe it’s the CDI switch box that is not firing one of my coil packs. So now I’m waiting on the switch box to get here!

[@TheAfterWorkGarage]

@@bigdummiegarage9022 It's always something with old motors, but either way it's probably good that you cleaned/rebuilt the carb regardless.

[@gerbs304]

@@bigdummiegarage9022 I have the same engine and rebuilt mine as well. I also read somewhere in a service manual that if u have one coil not firing, and its determined that the coil is ok...(switch them and try it), and your still not getting fire in that cyl, its most likely your ign stator that's bad! (as a matter of fact, it just says, "replace the ign stator"), no if's and's or buts about it... Hope this helps!!

[@bigdummiegarage9022]

@@gerbs304 I did end up figuring out that the one coil wire was not firing that was coming out of the switch box so I got a new switch box and motor runs like a champ now! The carb rebuild was just a plus that I’m glad I did!

[@HRxPaperStacks]

Thanks so much for posting this. I just got a 1989 mercury 35 and my carb looks just like this. It bogs down and dies when you put it in gear going very slow until you speed up just hair so I’m guessing one of those jets is clogged

[@charlierichardson1826]

Super Awesome INFORMATIVE Video. Thank u for posting this. My 3 carburetor are missing the brass jet on the side of the float bowl cover. Im not sure where I can get them. Can u send me a link to the website u used. Please.

[@MikeBauer-x1w]

I have this exact engine. I purchased the repair kit. The carb is leaking fuel from the air intake face of the carburetor. Any ideas as to what is causing this?

[@michaelmurtagh6486]

Also if you dont mind telling me how many turns did you back out that adjustment screw

[@christopherhubbard4842]

Great Video. I did have a question. Was there a small plastic bead on top of the idle jet?

[@TheAfterWorkGarage]

I didn't see this on mine, but it's also definitely nowhere near the original state it was in, so I can't say for sure how it was supposed to be.

[@Brapplifelife]

I have a question I have the same exact motor and I am having a problem to where it is not getting any fuel from the carburetor to the intake. I’m guessing the Jets are clogged because it will start when I spray starter fluid down the intake but as soon as it runs out a starter fluid, it shuts off, so definitely not getting fuel from the carburetors and yes, this video is gold. I’ve searched everywhere, and I got lucky to come across it. Is there anyway I can clean the jets without removing

[@jacobmiller416]

Was wondering if you could help me out with a shift shaft issue I have. At the top of the shaft under the carb there are two arms, one going to the shift cable, the other I don't know..? After some research, it seems that it may connect to nothing at all and be obsolete is this true? Mines an 1988 35hp, but who knows, might be the same.

[@TheAfterWorkGarage]

I'm not a Mercury expert by any means, but I could take some guesses. Are the arms connected or are they completely separate? If they are connected, it could be some sort of start in gear protection (so you can't start the motor in gear). Alternatively it could be a variation of a reverse lock to lock the motor down the the bracket when you put it in reverse. If they are completely separate arms, it's possible it has a function unrelated to shifting. Does it seem to be connected to anything, and for that matter, what type of connection does it have on it? Hopefully someone else may know better.

[@ArmedPatriot]

Where can ypu get a rebuild kit for those

[@Mudslinger2011]

Do you know what the starting point is for the idle mixture screws on a 1975 850 mercury outboard are? Mine quits when I put it in gear

[@TheAfterWorkGarage]

I'm not totally sure (though it's going to be one of the screws on the side of the carb). What is the non-load idle at, it could be as simple as bumping the idle up a little.

[@tmustard]

Is there any way you could get me the size of the Spring that sits in the middle of the float?

[@timfrank6183]

I set now ! Awsome !

[@TheAfterWorkGarage]

Good to hear! Glad it was helpful.

[@wushgreen1544]

Waiting for you to start it...

[@TheAfterWorkGarage]

As soon as I can find time to get back to KC to finish putting the dressings back on, I'll hopefully get that video shot and together. Thanks for hanging in there!

[@watcherwatchmen7785]

Do you know what that threaded hole at the bottom front of the carb bowl is used for? It appears that there's not anything in it in your video and mine appears empty too. I'm not the original owner, so I'm trying to figure out if anything is missing. Thanks!

[@landondunkin254]

Did you ever figure it out? My motor wont start unless I plug that hole

[@rdoehrman]

This kit work for the 35hp mercury too?

[@grantscime5708]

Where are you finding the parts for this engine I’m trying to find a fuel pump kit for this exact engine

[@TheAfterWorkGarage]

I can't remember where I got this exact kit from, but I believe the part number is 55278A 1. If you don't need the valves, Marine Engine.com (I have no affiliation) has the kit available here: www.marineengine.com/newparts/part_search.php?part_num=55278A%201 I'll let you know if I dig up my original order.

[@stanharrell4623]

How do you get the carburetor off the left bolt what do you use to get the nut off

[@TheAfterWorkGarage]

I had to take the top off of the carb bowl to get access to the left bolt.

[@denniskettel6183]

Did you have to remove any "red" sealant from brass screws on the bottom of your carb? If so... what did you use to soften/remove the sealant. My Merc same year and model has this. Screws are tight...OMG... Thanks for any help... Love your channel and this project...

[@michaelmurtagh6486]

nice video!Great detail and explaining.Would you know where I can get the little 90 fitting on that short hose?I broke it by accident.

[@BlockdAccount]

Part Number 22-196881. They're stupid expensive, over $70. I'd try a well stocked hardware store, some have a decent selection of brass fittings that might work.

[@michaelmurtagh6486]

@@BlockdAccount thanks for the input.i ended up buying a parts carburator and actually used it instead of the one I had.Runs great now

[@BlockdAccount]

@@michaelmurtagh6486 that's great! I need to find one for mine.

[@yijianggu5203]

Great video. my carb is leaking gasoline from the butterfly spindle. is it normal?

[@TheAfterWorkGarage]

That seems like an odd place for gas to be leaking out. Is it also coming back otu the front? and is it only leaking out at certain throttle settings?

[@yijianggu5203]

@@TheAfterWorkGarage , it is leaking from the vertical butterfly spindle. The gasoline coming from the main jet passes the spindle.I think it is normal

[@TheAfterWorkGarage]

@@yijianggu5203 Hmm, is there any fuel leaking out of the front of the carb when running, and is the motor running ok? Air and fuel should really only be going one way. others may know better, but this could be a jet/carb adjustment issue, or a similar reed valve problem to the one I was having with this motor.

[@yijianggu5203]

@@TheAfterWorkGarage No, there is no leaking out of the front. The motor runs fine

[@GringoSF]

I have a Mercury 400 year 82 that I start it up and it throws fuel through a pipe that is in the mouth of the carburetor

[@TheAfterWorkGarage]

If it's a lot of fuel, it's possible that the carb bowl needle valve/seat or valve float has gone bad, I'd check that first.

[@GringoSF]

The float spring had broken and I put in a new one. It wouldn't fit well. That would be it.

[@GringoSF]

How much does the height of the spring have to be in the float?

[@TheAfterWorkGarage]

@@GringoSF Unfortunately I don't know this, but I'm assuming if you buy a rebuild kit it should have an appropriate one with it. Sorry I'm not an expert on these motors, I just stumbled my way through getting mine working!

[@GringoSF]

thanks for the help, very good video of yours

[@jddeefo1022]

I'm looking at what seems to be a 80hp merc outboard, it is a barn find that sat outside for 15-20 yrs. I think its about a 1975. Is this the type of carbs that will be on the motor. The motor is free to me and will be my first outboard project

[@TheAfterWorkGarage]

That sounds like a great project! I can't speak exactly to the carbs on that motor (and on an 80 there will probably be 2), but if they have a side bowl like this one, then they likely are.

[@jddeefo1022]

@@TheAfterWorkGarage I just had a closer look, the serial# is 3060345. Can I find more info on the motor with this#. I couldn't read much else on the nameplate.

[@TheAfterWorkGarage]

@@jddeefo1022 Yes, you can definitely find your motor's model and year from the serial number. Usually I would recommend this site (www.maxrules.com/merc_contents.php) for a reference table, but I can't get it to pull up for me at the moment. Try searching 80 hp 1975 merc on Boats.net this can be a good resource too.

[@jddeefo1022]

@@TheAfterWorkGarage Thank you for the reply. I found this serial# on a label just above screws that hold the boat on the transom. When I search for info using the serial# nothing shows up. My 1975 is just a wild guess. I'll visit the boat again and have another look. I did take pictures but can't read much on them. Thanks again, your videos are the best I found!

[@TheAfterWorkGarage]

@@jddeefo1022 Thanks. It might be worth searching what you think it is in photos and see if you see one that looks similar. Mercury changed styles a lot, and you can usually narrow it down by looks as well. I also hope to get back to making videos in a few months (we'll see), as i moved for work, and now I am in a different state than my shop and tools lol.

[@quincywheeler82]

Thanx man!

[@hightechredneck506]

How wide does your carb butterfly open at WOT? I'm working on a similar engine, and I noticed at WOT mine maybe opens 1/3rd of the way. Thanks!

[@TheAfterWorkGarage]

Oh boy, I honestly can't remember. When I get it mounted back up, I'll let you know.

[@Mudslinger2011]

I had that same issue with my 850 merc, once I adjusted the throttle screw now my throttle plate is opening wide open and I gained rpm and top speed.

[@timfrank6183]

I'm also looking for the rebuild kit ! Any links !?

[@josephsmith5437]

Did you ever find a rebuild kit? I’m looking for one.

[@timfrank6183]

@@josephsmith5437 at about ten minutes into the video he shows the part #. I went online with that part number at got the kits from a marine out fit out of Florida. I will try and find their site and sent to you

[@demoll78]

Does it fit a 25 Mercury

[@TheAfterWorkGarage]

Mercury had MANY styles of motors during this period. So the best I can do is say you should look up your motor's serial number for the particular carb/carb kit for your motor. Sorry it's not an easy answer, but old mercs can be like that.

[@trictu]

Hey man you're videos in this series have been invaluable to me thank you so much. I bought a carb kit and have done the rebuild but I am not sure where the"throttle shaft return spring"goes. Do you know? A parts diagram shows it as part #30 and if shows it going somewhere on the bottom of the carb bowl towards the boat side but I can't seem to figure out how or where exactly. I didn't notice the part when I uninstalled the carb but I found mine on the floor and another in the rebuild kit. I've went through all your videos but the best I can tell, you didn't see it either or didn't remark on it. Update, I found it on another video. At the 6:50 mark, I can see the spring on the bottom end of the throttle shaft. kzbin.info/www/bejne/mIjEnmaNodeqd7c

[@TheAfterWorkGarage]

Thank you so much for the update and info, and I'm glad the videos were helpful! (sorry for the late reply!)

[@pjimmbojimmbo1990]

If you want that engine to live long, get rid of/disable the Back Drag Feature of the Carb. Fuels are different today than they were in the late 70s early 80s, and the Back Drag leans it out too much

[@watcherwatchmen7785]

How did you disable it? Just fit some tight fitting caps on each side where the hose connects? This reminds me of the SOS (Spawn of Satan) fuel vacuum assist on the 1983 honda CB 900 Custom that needs to be disabled.

[@pjimmbojimmbo1990]

@@watcherwatchmen7785 That is one way, another is to push a small ball(a bit bigger than inside of the hose) into the hose.

[@lonniewhitaker206]

Fuel enricher

[@BobbytheGreek]

lol "well it's three days later"

[@TheAfterWorkGarage]

There's always the plan, and then what really happens lol

[@Scott-ec4ux]

Mint * :-) ***********************

[@TheAfterWorkGarage]

Yes, like all the thing's I work on ;)

[@timfrank6183]

See