97 Yamaha prov150 choke issues

[Jstump18]

First off digging the forum as it is very informative ..
Well the engines a 1997 proV150 2stroke ( if anyone knows the actual model number of this motor fill me in because I've had quite the time finding it ), it has the push key choke on the ignition. Lately I've had to pop off the cowling and manually push down the choke linkage as someone's turning the key for it fire up. Once running it performs great .. when I press the key in to choke it I hear what I assume is the actuator clicking at the motor but the choke does not seem to engage anymore unless I press it down manually with my finger ?? Any thoughts are much appreciated
, Justin

[boscoe99]

The model will be on the data plate. Data plate is on the left hand clamp bracket. Also on the data plate will be the complete engine ID. More than likely you will find P150TLRV as the model.

The choke solenoid is activated by pressing the key switch in. When the choke solenoid activates it closes the choke plates. What you are doing when you pull the choke knob.

The linkage between the solenoid and the choke plates is held in place on the solenoid by a rubber O ring. That O ring gets brittle with age and can fail.

[Jstump18]

I'll check that out boscoe! Appreciate the help.. Yea the model number on that plate is so faded u can't read it .

[Jstump18]

Played around with it a bit . When I Push the key In the choke on the manual portion of it Does what it's supposed to do but as I'm sitting there holding the key trying to start it the linkage slips back out of that cylinder .. Whereas I'm assuming it should stay in there until I stop pressing the key in. Ill have to locate that O ring.

[Jason2tpa]

Played around with it a bit . When I Push the key In the choke on the manual portion of it Does what it's supposed to do but as I'm sitting there holding the key trying to start it the linkage slips back out of that cylinder .. Whereas I'm assuming it should stay in there until I stop pressing the key in. Ill have to locate that O ring.

As boscoe noted, there is a rubber o-ring that retains the solenoids linkage onto the carb choke. If the o-ring is missing, the linkage will separate from the carb choke, thereby causing the pushing in of the ignition key useless for the purpose of choke.

If the solenoid linkage needs to be disengaged prior to removing the silencer (like on my engine) to access carbs, and if you never knew of this o-ring, it's quite possible this is the reason there is no o-ring in place. It's so small that unless you knew of it then you'd look right over it. And once it's no longer where it should be, it's near impossible to locate it even if it's dropped onto the lower pan. It's that small. A $5 mistake. Which by the way, is a ridiculous price for a part so incredibly small. I've paid this price twice...the 1st time because mine was missing when I bought the engine...the 2nd time because I lost it while installing it. Sounds crazy, but like I mentioned it's very very small, thus difficult to manipulate onto and off of the linkage.

[Jason2tpa]

Played around with it a bit . When I Push the key In the choke on the manual portion of it Does what it's supposed to do but as I'm sitting there holding the key trying to start it the linkage slips back out of that cylinder .. Whereas I'm assuming it should stay in there until I stop pressing the key in. Ill have to locate that O ring.

As boscoe noted, there is a rubber o-ring that retains the solenoids linkage onto the carb choke. If the o-ring is missing, the linkage will separate from the carb choke, thereby causing the pushing in of the ignition key useless for the purpose of choke.

If the solenoid linkage needs to be disengaged prior to removing the silencer (like on my engine) to access carbs, and if you never knew of this o-ring, it's quite possible this is the reason there is no o-ring in place. It's so small that unless you knew of it then you'd look right over it. And once it's no longer where it should be, it's near impossible to locate it even if it's dropped onto the lower pan. It's that small. A $5 mistake. Which by the way, is a ridiculous price for a part so incredibly small. I've paid this price twice...the 1st time because mine was missing when I bought the engine...the 2nd time because I lost it while installing it. Sounds crazy, but like I mentioned it's very very small, thus difficult to manipulate onto and off of the linkage.

[rodbolt17]

if the choke blades start opening when your cranking fix the voltage drop issue.
if the starter eats up most avalible current there may not be enough left to operate the solenoid.
instead of opening the cowl why not pull the manual choke knob out?

[boscoe99]

if the choke blades start opening when your cranking fix the voltage drop issue.
if the starter eats up most avalible current there may not be enough left to operate the solenoid.
instead of opening the cowl why not pull the manual choke knob out?

Great point. Thanks for the reminder.

If the choke solenoid/choke plates work just fine on their own (key pushed in but motor not being cranked) but the motor won't start readily when it is cold when using the press to choke function, but the motor starts just fine when pulling the choke knob out, it could very well be a voltage drop issue. About a 99.9% probability that it is.

You think that this has ever been mentioned in a Yamaha service manual? I don't think so.

[Jason2tpa]

You think that this has ever been mentioned in a Yamaha service manual? I don't think so.

Perhaps in your spare time you can begin accruing what the Yam service manual does not include. After a year or so of collection and binding into its own manual, then offer it up for sale. I'll buy

[rodbolt17]

why bother? folks wont read a manual anyway.