Yamaha 115 choke issue...need troubleshooting help

[emerson281]

I have a 1999 Yamaha 115HP (C115TLRX). It has an electric choke (solenoid) that is activated by pushing the key in as you have the key turned into the start position. It is a momentary switch; as soon as you let up on the key, the choke returns to the normal position.

The problem is that when I push in on the key, the solenoid that is supposed to choke the two carbs by lifting some linkage up doesn't seem to have the power to do so. I see the plunger on the solenoid trying to raise up into the body of the solenoid and it does move a little bit, but it's just not strong enough to lift the linkage to active the chokes.

When I move the choke linkage manually; by hand directly at the linkage or by the manual level at the front base of the cowling, it moves smoothly and doesn't at all seem bound up or otherwise impeded...the solenoid should have no problem lifting the linkage into the choked position.

So, before I buy a solenoid assembly, is there some sort of troubleshooting method that I can use to verify that it needs to be replaced?

I plan to make sure that the ground wire for the solenoid is good and then check the voltage at the solenoid when the key is pushed in (although I'm not really sure what that reading should be...I'm guessing 6 or 12 V). I feel I should check the ignition switch as well, but it seems to me that if something is happening at the solenoid when the key is pushed in, then the ignition switch probably doing it's job....right?

I would really appreciate any guidance on how to proceed...I feel like I'm overlooking something.

Thanks,
Shane

 

[99yam40]

make sure the choke plates and linkage are not binding up

 

[ClassicAQ]

I'd first begin troubleshooting the part itself before testing ignition switch. The picture below is taken from your engines service manual. Follow the steps to test fuel enrichment valve continuity/resistance. I'm guessing by age of engine the enrichment valves wiring has corroded causing high resistance.

 

[emerson281]

I'd first begin troubleshooting the part itself before testing ignition switch. The picture below is taken from your engines service manual. Follow the steps to test fuel enrichment valve continuity/resistance. I'm guessing by age of engine the enrichment valves wiring has corroded causing high resistance.

Thank you for your response...very helpful. But, I just want to make sure: the "fuel enrichment valve" is the choke solenoid (the same thing)....right? I'm asking because all the parts diagrams for my motor refer to this part as only a "Solenoid" part # 6E5-86110-03-00....I can't find a reference to a "fuel enrichment valve".

 

[boscoe99]

The choke solenoid is called a solenoid in the parts catalog and a fuel enrichment valve in the service manual. Exact same part.

 

[emerson281]

And there you have it....thank you very much. The solenoid...er uh, the "fuel enrichment valve", is reading only 1.6 ohms. Out of spec. for sure. Ordered a new one.

BTW...I went ahead and cleaned the ground on the ignition switch and got it to work about half the time....electricity is weird.

 

[ClassicAQ]

The choke solenoid is called a solenoid in the parts catalog and a fuel enrichment valve in the service manual. Exact same part.

Typical, unfortunately.

 

[emerson281]

The new solenoid came in the mail. It measured right at 4.0, so the old one that was measuring 1.6 was the problem. The new one snaps the choke open strongly and consistently. The motor is still kind of a slow, cold starter, but better than it was when the choke didn't work consistently.

My successful start pattern: Pump the gas line bulb till taught. Turn over the motor for about 3-5 seconds without choke. Turn over the motor for 3-5 seconds with choke. While in neutral, advance the throttle to about 1/4 open. Turn over the motor using choke, be ready to back off the throttle a little after it catches fire.

Thanks for y'alls help.

 

[ClassicAQ]

The new solenoid came in the mail. It measured right at 4.0, so the old one that was measuring 1.6 was the problem. The new one snaps the choke open strongly and consistently. The motor is still kind of a slow, cold starter, but better than it was when the choke didn't work consistently.

My successful start pattern: Pump the gas line bulb till taught. Turn over the motor for about 3-5 seconds without choke. Turn over the motor for 3-5 seconds with choke. While in neutral, advance the throttle to about 1/4 open. Turn over the motor using choke, be ready to back off the throttle a little after it catches fire.

Thanks for y'alls help.

Glad to hear you located and fixed the problem, good job. I have the same engine as yours but 1 year older. Near 20 year old 2 strokes do not have a specific procedure for cold starting, as with age each engine forms its own quirks and whatnot. With that said, I would suggest using the choke upon initial cold cranking, as its purpose is specifically incorporated into the ignition system for cold starting.

My cold starting procedure is choking while cranking, along with having the neutral throttle slightly open. If it doesn't start after 3-5 seconds, I repeat. If it doesn't start, no choke and open the throttle a tad more. I never need to attempt cranking more than 3x.

What I also have noticed with my engine is if the engine didn't start after 1st cranking attempt, I recheck the primer bulb. 99% of the time the bulb is now partially tight, instead of it being fully tight as it was before initial cranking. I prime bulb again to tight and crank.