Four stroke carburettor synchronisation

In this video I go through tuning the carburettors on a four stroke outboard motor. This includes adjusting the mixture screws to get the fastest idle, reducing the idle and then using a carburettor synchroniser to balance the carburettors.
For outboard repair information, checkout my website: outboard.dangarmarine.com/guide
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Dangar Marine is proudly sponsored by MarineEngine.com. MarineEngine.com supplies a wide variety of spare parts for many brands of outboard motors. If you are in the US, be sure to check out their online store www.marineengine.com/
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[@giraffeapproved]

You're literally the only person on youtube that explain every detail!!! I've been struggling with syncing my motorcycle. This video helped immensely. MUCH appreciated.

[@kylenixon2352]

This has by far been the most instructional, informative video I have found to date.

[@DangarMarine]

Thanks mate, hope it helped you.

[@shanenelson1809]

Great comparison with tuning a guitar. Always a pleasure watching your tutorials especially with a stubbie in the foreground. Thank you!

[@DangarMarine]

My pleasure!

[@pitsmcgoo]

I have the same motor as you so this video is ideal. Ordered an equalizer and a cheap digital tach at half the price of 1 hours labor of my marine tech so once I tune there will be no doubt that it is done right. Thanks best video yet.

[@DangarMarine]

It's always nice when you can buy the tools to keep and still have spent less money. :)

[@braedenbrown6691]

Your videos on boat motor repairs are Thee Most Informative And Unmatched! I Always Enjoy Learning From You! Saying Thank You Isn’t Enough! Long Live, Dangar Stu⭐️⭐️⭐️⭐️⭐️🏌🏾‍♂️

[@Sam-qr9wu]

I don't even own a boat yet, but have been learning a lot through your videos. I really appreciate the clarity of your descriptions and speed at which you walk us through each procedure. When I find the right boat, I'll have a lot more confidence in surveying the condition of the engine. Thanks so much and keep them coming!

[@DangarMarine]

Thanks Sam. Sounds like you're going about it the right way to learn as much as you can before you choose your boat. Good luck!

[@slideglide9418]

You lay your money down, and take your chances.

[@jstump8617]

Dangar you are the fking man! You have helped me with countless of your videos and if you are ever over to the US and down in Florida I'm going to buy you some beers and take you out fishing. Thank you for your time to help myself and others become more proficient with their outboard engines. To the viewers reading this comment, always look for Dangar's videos first when troubleshooting or preparing to fix your next outboard issue!

[@DangarMarine]

Thanks mate, glad the vids have been helping you. :)

[@ml2trick]

I have been a Marine Mechanic in Wisconsin for 30+ years. Nice Video and i use the stainless slide type sync from Carbtune. Ordered it from overseas. 100.00 bucks. Love it and nothing better then carbs synced after a tune up.

[@DangarMarine]

Thanks mate, glad you liked the vid. I'll have to check out the tool you are referring to.

[@michaelchenery5854]

I like your plane down to earth approach to everything

[@tomasjonsson5174]

I have now watched all of your videos, some of them more than ten times. I have a 1995 Yamaha f50 and to be true I have never seen anything as pedagogic and useful as this chanel. Many many thanks from Sweden. I owe you.

[@DangarMarine]

Hi Thomas, glad the videos have been helping you. Safe boating! :)

[@brongthao6802]

I fixed my outboard by watching all your videos... Your the best!!

[@hookempescadosaustin4111]

Your demonstration videos are always the best for all outboard situations/conditions. Thx again!

[@DangarMarine]

Thanks mate.

[@61sixone]

I put my boat together from your vid’s I’m a expert now thank you

[@tbone344]

This worked like a charm. My BF30A purrs like a kitten now when trolling. Thank you very much.

[@stuartcollier2283]

The best mechanic TEACHER on you tube.

[@DangarMarine]

Thanks Stuart!

[@questionableprojects]

This was a great video and walkthrough!! the only bit of advice i would add is, when using multiple vac. gauges like that before you fine tune them its not a bad idea to check and see if they all read the same on 1 carb. sometimes those gauges can read a little differently but than after that you're set!!! great video!! new subscriber

[@slideglide9418]

Great tip Zac

[@levibellette7726]

Do you mean check 1 carb at a time ?

[@questionableprojects]

@@levibellette7726 no necessarily that. I just meant before you hook each gauge up to their own carb. check each gauge on the same carb first real quick! Iv'e had 1 out of 4 gauges read off before and messed up my whole tune! just a little tad of advice!:)

[@dekrev]

I use a mighty vac to test each gauge as a kind of calibration - 10” on the mighty vac reads 9” on gauge 1, 10” on gauges 2 and 3, 11” on gauge 4 - I then grease pencil a +1 on gauge 1 and -1 on gauge 4. Did that make sense? Ha!

[@questionableprojects]

@@dekrev ahah yupp, very nice!. too bad you can't just turn the gauge faceplate so the needle all reads the same. good idea though!

[@eliasrudnitsky3884]

I followed your procedure step by step for my bf25a and I gotta say...thank you so much for making this video...it helped me out so much when I had doubts about some of the screws effects.

[@milcool6827]

Stu I have watched soooo many of your videos. I can’t thank you enough. You’ve helped me do nearly everything for my Johnson and Yamaha outboards. Great work! Great info! Please keep them coming!

[@SSGSINCLAIR]

This video I felt was pretty cut and dry. Very helpful and it all made perfect sense to me. Thank you for taking the time to explain all of this. Great videos!

[@larryzuverink4423]

Thank You so much for your videos. I've been working on my sisters Mariner 45hp. These videos are so helpful. This started out as just replacing a bad Stator and turned into a Stator, Trigger, CDI, plugged idle valve on bottom carb. learned way more about outboards than I ever wanted to. :)

[@bornwildtv1317]

Can't thank you enough with words for taking the time to make this video for us. Thanks Stu!

[@DangarMarine]

Thanks mate, you're most welcome. :)

[@deweylee2449]

Very good and impressive video. I never knew there was so much involved in tuning the carburetors. Thanks Stu

[@steadyeddie7453]

I dont know if boat motor carbs have similar stages as automotive carbs but if so here's another tip. When you adjust the mixture screws you are adjusting the fuel through the idle circuit. If the engine rpm increases significantly while making the adjustment the carb will begin to draw fuel from the off-idle circuit, thus upsetting your adjustment. Best to keep the rpm adjusted to an idle speed as you adjust mixture screws so you're working within the idle circuit. Also, it looked like your vac hoses may have been partially pinched at around 23:37. But, as with your previous video's, you are clear and concise, and very detailed. Good videos, thanks.

[@sackman098]

I just want to say thank you for taking the time to really explain every detail of what you are doing and explaining everything in simple terms.

[@DangarMarine]

Thanks mate, glad you're enjoying the vids. :)

[@jeremymiller7993]

Great video and great information about turning your carbs. I think that you have given me the answer to the problem that I have been having.

[@pappysauce7959]

I appreciate you sharing this with us, it really helps. I tried to mechanically (as I don't have a vacuum gauge rack; which I will need to get) sync the carbs on my Honda 40 by setting the adjustments as close together as possible according to the small holes in the bottom of the circuit (lined up according to the boss carb.) We will see if it works, I know it did work on my motorcycle to do it that way. My motor was all jacked up...I cleaned the carbs and reset the mixture jets. Next is the sync, thanks mate for showing me how!

[@keithflowers9217]

Thank you, it really helps me understand what to do. Not difficult at all. Providing you have all the right test equipment and fittings.

[@danatavares2038]

Thanks very much for your well done, clear, and informative videos! I just got a 90 hp 3cyl merc running that hasn't run for over 12 yrs. cleaned and new gaskets in carbs, rebuild fuel pump, all new fuel lines. It runs pretty well but has,what I'm told, a lean pop, that will almost stop the engine. So next I'll do all you have shown in this video. Greatly appreciate your videos.

[@yomama69s]

This is BY FAR the best video that I've found on this subject for the backyard marine mechanic. Thank you, you just saved me a TON of time, money, and cursing. Cheers from Canada! Sub'd and liked.

[@DangarMarine]

Thanks Alex, glad you liked it. :)

[@timschenk658]

Great video. I work on cars all the time and now I know this is well within my realm

[@DangarMarine]

Glad it helped

[@sunnydeborahsebastian1361]

Super explanation! It was very concise, direct and not filled with a lot of technical engine mambo jumbo. I understood clearly everything as you explained it. Now I can’t wait for the sun to come up and I can try it for myself. Thanks for sharing your experience and knowledge with us.

[@cayetanodelcore9139]

just amazing , thanks very much,from Long Island NY.(Nino).

[@theheilious]

AWESOME!!! Thank you! Tthese videos have made me a lot more competent and confident to service my own motor. As a result, I've had a wonderful season on the water! Thanks again, sir!

[@DangarMarine]

That's what I like to hear. Glad you had a great season, I can't wait for ours to start! :)

[@theheilious]

@@DangarMarine , I imagine you are really busy but I can't seem to find the vacuum ports to put the synchronizer lines? 2005 Mariner 90hp 2 stroke. I've looked everywhere on the wen but nothing specific to my model?

[@racerxv6valvoline424]

Dangar, I am soooo very happy to have come across your videos. I have learned a lot on how to tackle things that I would have paid for in the past. Just last night I replaced my SS reeds with carbon fiber ones. Again thank you for the viedos and the time that you put into them.

[@DangarMarine]

Thanks mate, glad you are enjoying the vids. I think a vid on upgrading to carbon fibre reed valves would be an interesting one, been thinking about that for a while.

[@andrewnewsom4477]

Extremely helpful and clear, really appreciate it. I really enjoy all your vids, thanks!

[@DangarMarine]

Thanks Andrew, glad you enjoyed it. :)

[@ericneusiis404]

I have a Honda BF40 that I purchased used, I have worked on a ton of Honda's but your videos are AWESOME. Thank you for dedicating the time.

[@DangarMarine]

Thanks Eric, you're most welcome. :)

[@RaySmythe53]

Very useful information. I haven't done this since I tuned a Honda 4 cylinder motorcycle... so good refresher

[@DangarMarine]

Thanks Ray.

[@wg8847]

You are the most intelligent repair person i have seen..thanks man!!

[@darrenh20102]

Fantastic informative vid, thanks. Trying to sort out the carbs on a classic bike and my next search was gonna be how to get the mixture right, but I think you've covered it. Thank again and keep em coming

[@DangarMarine]

You're welcome mate. Yes, the process is pretty much the same for a motorbike.

[@aguafuerte]

Que capo que sos! gracias todos los videos que subís me están ayudando un montón! Saludos desde Argentina

[@joshcompton1564]

Great video. It was very helpful on getting my carbs back to normal after I like many others grabbed ahold of the wrong screws when I was trying to drain my carbs when they were gummed up. Rookie mistake. Thank you sir.

[@DangarMarine]

Nice work! Glad the video helped you. :)

[@helsinki4]

This video helped me get my 99 75hp Yamaha dialed in.

[@tonywizda]

The most helpful & nice video in KZbin!!! Thank you very very much!I slow down to 75% speed and saw this video 3 times. lol

[@erichmacho5741]

Thanks a ton! I am just about to endeavor doing this very task and you have clarified it for me perfectly.Now I know how to adjust the fuel idle mixture as with 3 carbys to do,I was somewhat clueless as to the proper procedure.This video makes it look a breeze and just as soon as I rebuilt them I'll be getting stuck into them.It makes it look so easy!

[@DangarMarine]

You're welcome mate, good luck with the tune up!

[@E-mobilizeEbikeRepair]

Great video ! Super helpful ! Stu is my favorite boat tech on KZbin! You are very clever and I like ur style !

[@QSSCEO]

I need to clean the carbs on my 50hp Honda....Now I know how to adjust them... Thanks!! Your video was very informative...Well done!

[@DangarMarine]

Thanks mate, glad it helped you. :)

[@rmcl8981]

I know this is an old post but thanks. Really Really helpful.

[@DangarMarine]

Glad it was helpful!

[@sammytrz]

love your videos! going through an old Johnson qd-14 and cd-11 your videos have helped tremendously.

[@DangarMarine]

Glad to help!

[@jeffb.4676]

Hi Sir. First class training video. Much appreciate. It helps me to understand the synchronization process with the tool, the small valves and the adaptors ... And your common sens tricks are great to know. Thanks, enjoy life ! Jeff

[@DangarMarine]

Thanks Jeff!

[@Simsy106]

I tell everyone to watch your videos you explain what your doing so well

[@DangarMarine]

Thanks Daniel!

[@donnykennedy4767]

I absolutely love watching all of your videos thank you for sharing your knowledge

[@SWhite-hp5xq]

The ol’ “Fender noise”.. no dog around to blame it on hey ;) Grea video mate cheers!

[@jondavis6231]

Really appreciate the competence and quality in your videos awesome dude

[@bryanhauschild4376]

Great job on explaining that, and how simple it is with the right tools.

[@DangarMarine]

Thanks Bryan!

[@ericcurole4535]

Your videos are very informative and you go in great detail. I will use this information to try & get my motor set. Thanks for the descriptive tutorial... will follow and looking forward to more.

[@DangarMarine]

Glad to help

[@aktrapper6126]

Very informative, thanks for making these boat motor videos.

[@DavAnge2022]

I've enjoyed viewing your videos tonight. They've given me that bit of motivation to soldier on. I've just spent the weekend on a Yammy F100AET (F100TLRZ) trying to figure out why the alarm sounds then it goes into Limp Mode. After cleaning sensors & changing oils I've come to the conclusion that I'm gonna have to go in hard.... remove the head as there's water in the sump and milk running from the leg. Also while I had the Sump plug out and the flush hose on, found water dripping from the sump plug. Thanks Dangar.

[@DangarMarine]

Good luck with getting the motor back in shape. I hope the videos help you do that. :)

[@drakeastro8131]

Ur instructions are clear, easy to understand and what I appreciate most is you explain everything that is going on and why. I had idle issues with my mercury 40 after a carb clean and after playing with the idle screws I could not get it to stabilise. Either too high or it dies. Did not know there was a setting to bring the whole rpm down to idle properly. Subscribed!!!

[@DangarMarine]

Thanks for subscribing! :)

[@AlfOfAllTrades]

I had a beast of a time adjusting a BF90. Two of the mixture screws had the tip broken off in the seats... I managed to drill them out with a magnifying glass and a dremel with a tiny, tiny drill bit. Installed new screws and redid the sync. Ran beautiful after that. It only took me a days work all in all :D

[@roberthowell3906]

Great vid on carbs. Always professional and most of all knowledgeable . Can’t tell what that means to DIY people like me great Job I feel inspired and excited and looking forward to getting back on the water with less stress or worries!!! Means a lot thanks Mate!!!

[@DangarMarine]

Glad to help

[@theluckystrike6371]

Very good video sir thank you from the 🇺🇸 North east!!!! 👍🏻👍🏻

[@theluckystrike6371]

I’m looking at purchasing a Honda 2006 Bf 40 tiller I’ve been told they are a good engine thoughts...?

[@DangarMarine]

Yes, those Hondas are very good engines.

[@exup250]

Love your technical videos. I hadn't thought of it like a guitar string before, but its spot on! If you want carb exact, it needs to be adjusted everytime you use it, or if temperature or humidity changes...just like a guitar. I've just got a boat, but been mucking around with 2t dirt bikes for a while, good to know its basically the same.

[@ct1762]

carbs can last sometimes 20 years with zero adjustments if non-ethanol fuel is used. they are extremely reliable pieces of engineering on most brands and models, especially outboards starting in the early 1980's. temp and humidity will change this yes, but such a small amount it wouldnt be worth the trouble.

[@exup250]

@@ct1762 yeah I guess it helps with outboards considering they are mostly used at one level (sea level or at a particular lake), so no need to adjust for altitude. But 2t dirt bikes will always run better if they are adjusted for the conditions of the day.

[@shanec.7105]

You are very knowledgeable and a good teacher.

[@GringoSF]

The most informative video I've seen on this topic. Thanks for that

[@DangarMarine]

You're welcome, glad you liked it. :)

[@benjaminrich9396]

As a predominantly motorcycle and car mechanic who puts tools down everywhere I'm always anxious for you when watching your vids of tools or parts going in the water. ☺ Nice video mate.

[@DangarMarine]

I hear you brother, I'm always losing tools in the workshop so I try to be more careful on the water but it doesn't always go to plan...

[@arcanetraditions]

I keep a large magnet on a rope for retrieving tools lost off the boat or dock, seems to work alright.

[@boosted_l6787]

That sir was the best explanation i have ever heard, thankyou very much

[@DangarMarine]

You're welcome, glad the video helped you.

[@joshhall6531]

Great video, very clear and easy to follow along. Thanks a million!

[@redartisanwolf6716]

awesome video . i learned so much in 30 min. tomorrow i will do the same to my 60 horse mariner after a few upgrades.

[@DangarMarine]

Thanks mate, good luck!

[@Erated78]

On my 2006 merc 125 hp the it really idles hi and clunks into gear. I wasn't sure the idle was to blame but this vid narrowed that down nicely. While I'm not sure I want to start turning fuel screws I might just simply lower the idle as you say until is comfortably slower but not out of balance. Thanks Stu, very well explained video as always....cheers

[@DangarMarine]

For sure I would lower the idle if it is really clunking. As you say, no need to mess with the mixture screws if it is running nicely.

[@bobcanupp3184]

Super informative and so very helpful. Getting ready to adjust my own and this gives me the needed knowledge.

[@DangarMarine]

Glad it was helpful!

[@charleswood6674]

Thanks for this. I have a new (to me) 1998 115 Johnson running rich. I hope this applies. As soon as Hurricane Harvey is done thrashing us here in south TX I'm going to give it a go. Keep up the good work!

[@DangarMarine]

Thanks Charles, the mixture screw part should solve your problem. Stay safe in the Hurricane!

[@LordoftheCats]

Good video. I learned quite a bit and ready to tackle tuning up my outboard.

[@DangarMarine]

Thanks mate, good luck with the tune up. :)

[@eric14nn13lcfd]

Man I have to say... Your videos have been so helpful. I have been working with 98 Johnson 60hp 2 stroke. Everything from the reed valves video to the card clean and sync videos. Keep up the good work!! Now I have to find the Vac screws on my in take and do a sync I have the motor running fairly good. Just some last fine tuning.

[@DangarMarine]

Hey Eric, glad the videos have been helping you. 2 stroke motors don't have induction runners like 4 stroke motors so this is more the procedure you would follow kzbin.info/www/bejne/hJ_SpYSjo7Crga8

[@tuomaspetlin92]

Thanks, I have done that to my Suzuki GSX-F 750 with same type of synchronizer. Nice to learn more and now with boat engines.

[@cpalmer69]

Thanks for the breakdown it showed me exactly what i needed to know

[@andyfritz7177]

This was a great video how I explained each carburetor may be adjusted a little different.

[@mbearden]

Best material on outboard tuning I've seen! I have a BF25 Honda that looks to be quite similar to what you're working on so even better for me. I've struggled a bit with this motor the last several years but the trend is positive :). Have had issues with dirty fuel and build-ups in the very small passages in the carbs so have, of necessity, gotten comfortable with disassembling / cleaning these guys. The final tuning / balancing however, has been a work-in-process even with the factory manual but your video puts it all together beautifully! Thanks much (and big snaps for not dropping anything in the water at the dock...I can't claim the same when working on the boat in the water :).

[@DangarMarine]

Thanks Mark, yep, those BF25s are very similar. Glad to hear the videos have been helping you, but yes, I have dropped plenty of tools and parts in the water over the years...

[@alanbett6336]

Dangar Marine Tappets

[@sgtcaco]

Really good tutorial. Perfect actually.

[@fliegenbet]

Thanks again for your helpful Videos. Keep up the great work... From Germany

[@suzukiclarke]

Awesome thanks Stu. Ive got similar on my BF45. Cutting out at 1200rpm as trying to accelerate. Picking running too lean/and or cold, have ordered replacement thermostat to replace to missing current one.

[@petersgarage6125]

Just subscribed. Easy to follow common sense tutorials on marine maintenance. Happy Boatie.

[@charithpadmajithpalihaderu5253]

Thanks a lot sir... we love your presentations and great videos ... carry on .. god bless you

[@Whitboxphotohk]

Somehow I just aquired a pair of BF50's one has a bum Trim Motor, the other has dirty carbs, thanks to you, I'll soon have 2 sweet running 50s :) ( on a 15' Boston Whaler, weeee).

[@DangarMarine]

Good score! Sounds like it's going to be a sweet setup once you've got it up and running. :)

[@yyabadabado1]

Very well presented even for the simplest of us

[@duanebethea]

Great video. Thanks for taking time to explain all this information ...

[@DangarMarine]

You're welcome Duane, glad you enjoyed. :)

[@hartfordboothe7466]

I really like your videos, you do a good job. Not to be "that guy" but: I had a Honda twin cylinder motorcycle 17 years ago, first street bike, and got all excited about stuff and found that I could balance the carbs (never had heard of such a thing prior to that). I bought a gauge/device and balanced them. I can't quantify it but it definitely seemed to run better and stronger after balancing the carburetors. It didn't turn it into a rocket ship, but it seemed to make an appreciable difference. I think it's a good final step in tweaking a carb engine.

[@locknloadbitch]

Very interesting and informative. Thank you !

[@DangarMarine]

You're welcome. :)

[@crispernator]

Gday mate another brilliant video ,this was always something i would take tomy outboard mech ,1 i didnt have the vac gauges and 2 i wasnt confident as i had never done it before or been shown , brave man doing it over the water my luck i would have dropped all the screws and the screwdriver in .

[@DangarMarine]

Oh yes, I've certainly dropped my fair share of tools in the water!

[@falconeaterf15]

Fun fact: Mercuruiser stern drives have an interrupter switch that actually turns ignition off for a few milli seconds as the unit is shifted from neutral . This protects the shift components in the bottom end. Works quite well. Don't know if outboards have similar tech, but they should imho.

[@ct1762]

yes of course outboards have a "shift interrupter" switch. if its a v4, kills one bank of cylinders so its easy on the pinion gear. a V6, 3 cyl (entire port or std. bank). anything smaller than a v4 and its not an issue. although many v4's dont need one depending on the gearcase.

[@timothyreed6054]

I'll echo what others have said.Very clear explanations. I learned a lot.Thank's for the great video.

[@DangarMarine]

Thanks Tim, glad you liked it.

[@raymondcummings331]

Doing it all from the dock too, you're the man😎

[@DangarMarine]

Got to be careful not to drop anything in the water!

[@davidlang5278]

Brilliant clear explanation. Thanks. VERY helpful.

[@DangarMarine]

You're welcome!

[@roberthargrave573]

Great videos Stu very interesting to watch

[@deenicolaOH]

Thank you, you are very thorough

[@Agentwade1]

Thank You for the info... my Yamaha is displaying sun tens after sitting up for many years ... Motor looks new but has been neglected and I’m Playing catch up ... I first thing I will do is replace all vacuum hoses and fuel hose as cracks have been seen .. Motor will not idle correctly and is really rough ... the carbs have been clean thoroughly with new jets and Orings.. To sum it up thank you for your time In explaining the Symantec’s and what’s involved ..

[@hobrealy]

This guy is awesome! Thanx for the great information

[@DangarMarine]

You're welcome Robert. :)

[@advancednutritioninc908]

great job on your explanation !! thank you for making it simple!

[@DangarMarine]

You're welcome, glad you found the video clear. :)

[@BrightonRich]

As usual very, very useful - much appreciated

[@pauldiegnau3492]

You make the best videos! Thank you!

[@DangarMarine]

Thanks Paul!

[@j.davidcox3783]

For a doofus like me, you working on what looks like a Honda 50 (my motor) is HUGE! Thanks.

[@DangarMarine]

You're welcome. This is a 40 but the principle is the same for almost all four strokes.

[@j.davidcox3783]

I meant to add.......you tube is great but too many guys think they are media personalities or leave the camera on while they tighten a bolt. You get straight to the point and there are no 'dull' parts where I have to watch you spray paint the engine or something asinine. In other words, you are not just a good mechanic and a great you-tuber, you are also a great editor. Much appreciated.

[@DangarMarine]

Thanks mate. I know I go through quite a bit of talking theory in some videos but I try not to make them too boring! :)