Thread: Yamaha 50 2 stroke carburetor ???????

probly debris in the needle and seat, keeping it from shuting off fuel flow. those are very easy carbs to clean and rebuild. they don't need rebuild kits, they have reuseable gaskets. but marines parts will sell you them. it would be best to pull all 3 carbs, take them apart, keeping everything separated, soak em' in carb/ parts cleaner over nite (NO RUBBER OR PLASTIC PARTS IN CLEANER), blow em out with compressed air, spray rubber gaskets with wd-40, and put em' back together. set air/ fuel adjusting screws ( 1 on each carb) 1 1/2 turns out. you'll have to fine tune them once the motor gets warmed up, best to fine tune on the water. remember to replace the plugs, i'm sure that 1 in the lower cylinder is fuel soaked. i dont care for those factory installed fuel filters. i like you run a paper element filter as close to the carbs as possible, i wanna see whats in the fuel line before it hits the carbs. or, if you're not worried about the other 2 carbs, you could just pull the drain plug out of the lower carb, disconnect the fuel hose from the lower carb, and spary carb cleaner in the fuel inlet, hoping to wash out debris. but, i would feel more at ease, if i all 3 carbs where cleaned. i can get a parts diagram of them carbs for you, just give me the year and model # of the motor. they are the easiest carbs i have ever had to get into, don't even have to get into timing when taking them off. good luck, rick

Thanks for the info. I did install an inline fuel filter on the fuel line. I guess the only part I don't understand is the air/fuel adjusting screw being 1 1/2 turns out. The model is a 50 TLR 2007. I think i will go ahead and take the carbs off and do the cleaning like you recommend then change the plugs out. Never done any carb work before but hey first time for everything.

there really easy. the adjudting screws are on each carb, on side, up near top, you can see a spring under the screw, its got a slot in in for a flat head screw driver. at 1 1/2 turn out from at SLIGHTLY SEATED(CLOSED POSITION). i'll get that dia gram for you.

looks like you have injection pumps, no carbs. and sierra parts are only showing carbs kits up to 2004 for yamaha 50 hp. maybe you can fine you model here. OEM Parts heres seirra carb kits Sierra Marine Engine Parts Catalog

i found a f50tlrc 2004. thats the latest carbed 50 hp yamaha i can find. the lastest carbs i've had to do for a yamaha was a 04' 40hp. i havnt gottin into any injecter motors. i got a yamaha 85, but i believe its an older 1, like 89' or so. i hope i helped you out in someway.

This is a is a pict of what I have. Not sure if this is what you were thinking about.

I agree with all advice above. Boats.net will have parts and diagrams for your engine. It's possible it could be a hole in the float but doubtful. I think that it's more likely trash in the float needle seat as mentioned above.
I agree that the carbs are very simple to clean just make sure you don't change any linkage adjustment and check to see that they're still synchronized. Just make sure both throttle plates are fully opened with the throttle level all the way forward, and that the throttle plates are almost totally closed in neutral at idle.
Don't try to remove the high speed jets if you don't have the proper tool, just spray them out really good with carb cleaner and run a copper wire through them if you have to---be gentle and don't scratch anything!
JBJ

Spanky, the carbs on you're motor probably have plastic caps on the idle adjust screws. If you remove the plastic. It looks like a p.t.o. on a tractor, best I can describe it. Hard as hello to adjust and they will break off in you're carb. I've heard a few stories on why they do this but can't say which is true. This is what i can say. The carbs on that motor are made by TACC. Same company that makes them for Tohatsu. If you have a Tohatsu dealership near you. You can buy the set screws from them. I promise they will fit in you're yamaha. They may look a little different but they do the same thing. These are the ones previously mentioned that you can adjust with a flat head screwdriver. I did this same thing for a buddy last week with a 2007 25hp yamaha. Also like previously discussed, tighten them all the way up then back them out 1.5 turns. It may not be perfect but it will be close. Total adjustment will be between 1 and 2 turns. 1.5 is midway and where most guys start. Good luck and I hope this helps.