Possible auto choke problem

[sonnlaw]

Hello,
I am a newbie here and have a slight problem with my outboard. I have an 03 Yamaha 40 hp tiller handle 2 stroke. I bought it new and it has run flawlessly thus far but now I am having what I feel is a fuel issue. At the beginning of this season the motor was very hard to start, I took the carbs apart and seen gelling so I cleaned them as thoroughly as I could.
Now the motor will start and idle just fine after priming the bulb but once you put a load or try to accelerate it will stall. I have remedied the problem by using the manual choke to half choke until mid range or so then I can flip to off choke and it runs great. But once I stop I can not re accelerate without going through the entire process again. I feel kind of funny running down the lake with the cowl off!
Essentially my procedure is as follows now: prime bulb, start, idle off trailer, half choke until mid range (starts to stumble), off choke until out of gas I assume!
Could this be the auto choke acting up? All I did was unscrew it from the carb housing when cleaning them. Thanks immensely.

 

[99yam40]

Re: Possible auto choke problem

you did not give us the whole model # , so I am assuming from what you have said, that the motor is not prime start with the emergency switch and it has the butterfly style choke. It helps if you give the model # and serial # if it is a newer motor.

Anyway it sounds like you still have a problem with the passages in the carbs being plugged. You need to make sure you disassemble completely and clean with carb cleaner and blow out all passages with compressed air. If it is prime start you need to take it apart also and clean and inspect. When you reinstall you need to do a sync and link adjustment as the manual says along with the idle screw and idle speed adjustments. It would not hurt to check the timing with a timing light just to make sure it is where it should be.

 

[sonnlaw]

Re: Possible auto choke problem

Thank you. It is a butterfly style choke. I do have another problem, my house burnt Dec of 08 and the manuals were in there. How do you do a linkage sync?
The idle and timing I can do but I have no way to know how to sync. Last, I have a really dumb question, are all three carbs the same as far as jetting? I pulled all the jets and soaked them in B12 overnight and honestly never even checked that, I assumed they are all the same.
Thank you ALOT!

 

[99yam40]

Re: Possible auto choke problem

Mine shows the top and bottom carb with #115 and the mid with #118.

Here is a thread that May help on the sync

http://forums.iboats.com/showthread.php?t=366637

 

[sonnlaw]

Re: Possible auto choke problem

Thank you again. I will clean the carbs once more and be for certain the jetting is in the right place.
It seems there is some confusion on the link sync procedure from the mentioned thread. I will adjust with all the valves closed and go from there. If it is not right a trip to the stealership may be in order then . I am comfortable messing with single carb atvs but have no practice with multi cylinder engines, as you can see. As stated, I assumed when I should not have. But, a man has to ask questions to learn, so thank you for answering.
Last, is there a particular site one should use for ordering parts? I am needing a trim tilt switch for my tiller handle.
My boat has been flawless for 7 years now but it wants attention now!

 

[99yam40]

Re: Possible auto choke problem

This site sells part along with lots of others. I always compare the part prices and the shipping before ordering.