My 40hp would barely run and carbs were cleaned, I did the jet swap out and now it runs awesome, balanced the carbs and popped in new plugs and now it just purrs. No more cold blooded starts either! Thanks for info. Rick

My 40hp Yamaha ran like crap for years. It's been getting worse every year. I tried everything (clean carbs, plugs, valve timing). I was about to give up and buy a new motor. I knew it was a carb issue. Cleaning helped but it never solved the hesitation problems. Decided to give this fix a try. It now works great. Thanks for the video!! It really helped.

Man im proud of all these videos they are verry helpful!!!!!!!!

2002 ran bad rebuild it 5 times did you fix ran the best I can every remember today idling for hours and about 4.5 miles per hour faster 25.5 mph on 16 foot SSV lund thank you feels like a new boat

I just took the next size drill bit and made the holes bigger in my 40hp jet drive and it runs great now !!!!!!!!

I have a fifty hp. It runs great so long as one condition is met. Only use NON-ethanol gas. Violate that rule, and let it sit up any length of time and you’re screwed. I had the carbs rebuilt and followed this rule and even stored it for a year. It cranked on the first try and ran like a top. Then a cheap ass pendejo nephew ran ethanol thru it and it’s back to having the high speed jets clogged.

I’ve got the same motor but a 2008. Running rough and seems to be starving for fuel. Removed jets and cleaned them with compressed air; all jet ports are clear. Still can’t seem to get it to run smooth. Thinking of trying the oversized jets.

Yeah did the same to my f40 4 years ago...runs perfect

good afternoon, please which initial adjustment of the carburettor air bolts, on yamaha 60 fed thanks

gonna try this this week. I have same problem. Idles fine but bogs down when cranked.

Hi! How do you disconnect the linkage from the three carbs. It looks like the same as on my Mercury 40, but I can't figure out what to do with the vinyl "washers" that connects the linkage and the carbs. There is no locking pin at any of the three carb connectors

Wonder if the fuel pumps on these things have issues. Read somewhere that the fuel pump should last for years. Verified the check flapper valves inside; they look fine and are sitting square over the port.

Did you back the jets out at all after you tightened them down? I think it's that or a float is stuck cause I'm leaking gas out of the carbs

Did you do all three carburetors with it Jets or just the one

Hello. what is the difference between yamaha f30 and f40 carburetors? just the jet diameter? Or different diffusers? what is the diameter of the diffuser on the f40?

I am be check on one

Quick question. Just did the jets on my 05 40HP Yamaha do I need to adjust pilot jets before doing the sync ? Can’t find out anywhere. Thanks

Can i put a 40 hp. yamaha carburetor on my 25 hp yamaha four stroke for more power?

will this work on 02 yamaha 50hp 4stroke?

what is the Membrane Carburateur can past to my yamaha cygnus x 125cc 2006 PLZ plz

Con cuál carburadores son compatible mas

did you just clean the old jets or did you buy the kits for the 40 carbs that comes with new jets?

Thanks for the video and thank you very much for the reply what I'm looking for is the number three carburetor the lower one A friend of mine had bought a 2004 four stroke 40 horse Yamaha and the guys took advantage of him right at the start unfortunately I wasn't here to help him go check out the motor I was out of town for a few years but anyhow and didn't even sell it to him with a prop and the guy I'm talking about is disabled he's on a walker he's got killed himself in his pickup truck and the guy just took advantage of him and he put the motor on the boat and start having problems right from the start and the guy wouldn't stand behind it so he got other people to work on it and then I come back in town and I seen him he asked me if I look at I did all the bolts were loose on all the carburetors social carburetors off and look at them and they are all full of hazy white scaly stuff except for the number three the bottom one it was just full of water and just hard and rock crap all over so I need your number three carburetor and I do thank you so much for your reply and keep up the good work

I have a 90 hrs power yamaha.. and i would like to do the same when i open my carburetor... can u help me pls...when i do the upgrade.. maybe a site i can visit to see the proper size # of jets.. thank you...

Friede sei mit dir. Ich habe ein Problem mit Benzinlecks .yamaha 40hp 4storek

I just bought a 16' Achilles with a 40hp 2 stroke, ran great the 1st day out but not won't stay on idle unless I have the choke half way out. I'm thinking I might have to do the the same thing as you did. It's such a clean motor, the kid I bought it from really took care of it so what ever the issue is I'm sure it's a small one. Sat for a while so it probably sucked some crap into the jets?

Same motor, #2 cyl does not fire at iddle. Have compression, and spark, when a cleaner is sprayed into manifold port if purrs like a kitten! Cleaning carb now, not sure what passage might be the issue?

Did you blow up this motor yet? Being serious getting ready to try it

I have the exact same motor. When I run it in neutral everything is fine, but as soon as I put it in forward gear and give it gas after it stops I check the timing belt and it is off by 3 or 4 grooves. The timing belt is brand new and fits tightly. The other thing is when I run it out the water on the ears and accelerate the motor runs good except for the timing belt problem. When it is ran in the water I can’t get it to half throttle until it starts to bog down. It only bogs down like when submerged in the water. Any ideas on what it could be?

I bet you saw my video on this lol

Does this engine have a carburetor bowl and if so where is it located?

That motor shakes.I am familiar with those engines.That motor sounds like shit 2.I can show you what a properly tunes 40 looks like.You can put a cup of coffee on the engine and it would not shake off.The problem is where the plunger and spring lay in the bowl.I never put different jets in those carbs.All they need is a proper cleaning and the plunger varnish is a must do service.