Yamaha 40 4 stroke question

[david18]

I am working on a 2000 model Yamaha 40 4 stroke (tiller handle-rope start) that is very cold natured. I have been thru the carbs 3 times and all seems clear and the acc pumps seems to work. On the top carb there is a white plastic device with a short plunger and 2 yellow wires. My question is: Is this thing supposed to be a choke or enrichener device? I hooked up some leads that touched the yellow wires to a battery with no results. If this is supposed to have power, how is it supposed to work on a non-electric motor?

 

[rodbolt]

Re: Yamaha 40 4 stroke question

its an enrichment valve, cold the needle is retracted, as it heats the needle extends.
power is tapped from a power bobbin under the flywheel, similar to the lighting coil.
test it with 12V. rod should fully extend in a few minutes and be retracted when cold.

 

[longshanks]

Re: Yamaha 40 4 stroke question

I realize this is an old thread, but we have a 40/30 2007 Yamaha Jet motor that has been very difficult to start also. The owner's manual has no information about any sort of choke/enrichener, and the motor is a manual start model. I checked the top carb and it has the white/yellow enrichener valve that Rodbolt noted, but most days this motor has been used, the guys are saying it takes 20-30 pulls to start it. We had some carb problems with the motor not starting when hot, but the dealer resolved them.

Strange that it isn't mentioned in the owner's manual, but cracking the throttle to WoT momentarily and back ot start position, then pulling the starter rope, the motor starts on the 2nd pull every time.

hope this helps.