150txrc auto choke failure

[Psalm 99]

Engine is a 2004 Yamaha 2-stroke, 150 TXRC. Engine has been hard to start the last few times out. Removed air intake & noticed that the choke solenoid wasn't working. Removed solenoid, checked coil ohms (4.1 ohms - OK) and applied 12 v across black/blue leads - OK. I replaced the starter switch about a year ago and everything was working fine. Manual's picture indicates a small electrical device (with a coil) along with a diode in the power wiring to the choke solenoid (manual calls all this a 'fuel enrichment valve'. Manual choke @ engine works fine but I'd like to be able to choke the engine from the helm. I will test the voltage to the solenoid but its either too low or non-existent as the solenoid works fine when in shop and 12 v applied to leads. Sure appreciate all the help I've received on this Forum.

[boscoe99]

Aloha.

The system is pretty simple. The choke solenoid is grounded on the motor. 12 volts is applied by either pressing in the key switch or activating a toggle switch. Depends on the particular switch panel.

Connect the positive lead of your voltmeter to the female bullet connector on the blue wire. The connector that normally connects to a male bullet connector that is attached to the solenoid. The black voltmeter lead will be connected to the block. Have someone press the key in or press the toggle switch. You should see 12 volts indicated on the meter. If not, you have a wiring issue or a switch issue.

Another issue with the choke solenoid is that an O ring is used to connect it to the choke plate linkage. Easy enough for that O ring to fail and need to be replaced.



Oh, if you have voltage to the bullet connector with the key pressed, and the known good solenoid does not work with the key pressed in, connect the female bullet connector to the male bullet connector and then retest for voltage to the connector.

bookemdanno murderone

[Psalm 99]

Good advice as always. initial voltage to solenoid was 5.45 volts then dropped rapidly to almost 0. Disconnected wiring harness @ helm switch and re-connected. Voltage went up to 11.45 volts & solenoid correctly shut choke plates. On second try it failed. Disconnected harness again and sprayed with CRC electronic cleaner both ends. Also sprayed keyway. Got full 12+ volts to solenoid and device continued to work thereafter. This Forum is great!