Yamaha T9.9erly cold start problem

[robin99]

On my Yamaha T9.9erly cold start problem I can get the motor running by manually choking at the carb throat. But I want it to cold start properly. The carb is clean and the motor is like new. There is a black soleniod on top of the carb the pulls up a needle valve. Looks like is could be a cold start fuel enrichment valve but I don't know. The solenoid has 7.2 ohms across the two black wire leads. How is this device supposed to work? Does is pull in with 12vdc or some other signal? I traced to two black wires and they go up into the magneto? Can anybody send me a wiring diagram or explain what the problem might be?
Thanks,
Robin. Canada, freezing here.

 

[rodbolt]

Re: Yamaha T9.9erly cold start problem

that solinoid is indeed an enrichment device.
it works by heating a wax pellet inside.
when cold the needle retracts allowing more fuel through the enrichment circuits to the carb idle circuits.
as the engine runs and the current from the stator lighting coil heats the wax pellet the needle extends closing off the enrichment circuits.
however if the carb is not in top shape or the engine has other running issues it wont work properly.
if the throttle shutter is open when cranking it wont work.

 

[n6rfm]

Re: Yamaha T9.9erly cold start problem

Robin,

You might also want to take a look at the carb fuel passages again. I had a similar hard starting problem on my T9.9, recently. My mechanic told me he found a bit of crud in what he called a "cross-over" passage, even after I thought I had everything cleaned out. he said it was part of the enrichment circuit.

Good Luck.

Bob