Need help whit the "automatic choke" on a F50 2000 model 4stroke

[Eirikhau]

Hello,
hopefully someone here has some knowledge too help me whit something.


im im having big issues whit this thing. the "choke".

I have a 2000 modell F50 4stroke yamaha, and i can start the engien just fine.
but it runs very high on RPM when ideling, around 1900rpms.
and after a minutt it starts too run high, i have too turn the engien off when it hits 3500rpms.

but, when i press down the levers on the carbs that the "choke" is supose too control it runs smoothly on 900rpms. and it can run like that forever, as long as i keep the levers down.

i see that the "choke" is not moving, it only moves for like a second while i turn on the engien, but when it has started it stops working.

iv traced the wiring too the starter relay, and iv mesured the voltage on the "choke" i get voltage there just as i turn the engien on, but as soon as i let go of the key and its started it looses all voltage and stops working.

i tried too use another circut with constant voltage just too see if it was working, and then the "choked" worked fine, it was holding down the leveres, but then i couldnt use the throttle too give it gas, too gain rpm because it was holding the leveres constantly down, and the engien just bogged down and died, so im guessing it should be getting variabels voltages?

hopefully someone here can help me so i can save the rest of the season overe here, and sorry for my poor english, im norwegian and living up here in the cold north, and only got a few more weeks of summer before the real cold sets in

whats wrong? anyone have any idea?

the choke is supose too adjust these leveres.
(hopefully the image works)

[TownsendsFJR1300]

Your pic didn't post.

Here's the parts fisch for your choke assembly(or should be close as yours is likely a non US engine);

2000 F50TLRY Yamaha Outboard CARBURETOR LINK Diagram and Parts

I have no idea how yours works. You may double check your parts against the fisch and let someone chime in familiar with it..

[Eirikhau]

cheers.

but i cant use that too see where the choke-coil is supose too be connected?

[zenoahphobic]

cheers.

but i cant use that too see where the choke-coil is supose too be connected?

Agree, looks like it is No22 a spring doing the actuation to me.

[Eirikhau]

yeah, but No.22 is justa spring thats holding something passivly....

but where doo the choke coil get electricity from? should it be connected too the starter relay?

[Eirikhau]

[Eirikhau]

iv added photos of the items here, the starteer relay wich i find out is giving power too the choke coil, but only for a second like when im starting engien up.

a pic of the levers on the carbs that the choke coild should be adjusting.
and a pic of the choke coil

[TownsendsFJR1300]

Looking at your pic's and the parts fisch, it appears part #9 plugs into part #36 (two wires each). 2 males to 2 female plugs.

And on that 3rd pic, someones dinked with that spring, part #22 big time and destroyed it. That needs to be pitched. With the correct spring, it should help to figure out where it goes (probably the choke linkage)

Do you have part #28?


**It might be a big help to blow up the parts fisch, PRINT IT and hold it next to your engine. It'd be a lot easier to see what's been screwed with/missing

[Eirikhau]

Looking at your pic's and the parts fisch, it appears part #9 plugs into part #36 (two wires each). 2 males to 2 female plugs.

And on that 3rd pic, someones dinked with that spring, part #22 big time and destroyed it. That needs to be pitched. With the correct spring, it should help to figure out where it goes (probably the choke linkage)

Do you have part #28?


**It might be a big help to blow up the parts fisch, PRINT IT and hold it next to your engine. It'd be a lot easier to see what's been screwed with/missing

Jess, i have every part. i tok the choke apart just too look at it what it was build like, and put it back toogheter(pretty simpel desig whit coile and a shaft)

but im wondering if its only supose too get voltage right at the moment i start the engien?
because when it dosent get any voltage, the shaft just hangs there freely and dosent keep track of the levers thats on the carbs, so the levers dont go down towards the screw that adjust the idling rpm, it moves up so it gets more rpm than it should. as u see in the pic that i can put a finger on the levers and hold em down an the engien runs smoothly at around 8-900 rpms.

as i said iv traced the + wiring too the starter relay, and that only gives out voltage at starting point.
so as i start the enigen the shaft moves corectly(i guess?) and the engien starts nicely, but at around 1900rpms idleing....

i tried too messure the voltage at starting point, but was diffucult trying too messure and start at the same time, and i messured around 7V at starting point that whent too the coil.

[99yam40]

The choke should only operate the choke linkage/ butterfly valves at start up,if it kept the valves closed then it would flood out.

the throttle cable and linkage should be the ones that control the idle RPMs.
I believe the ECU will control the timing and if the timing is too far advanced the the RPM will go up. But make sure the throttle butterfly valves are closing off as they should before chasing other things

[Eirikhau]

The choke should only operate the choke linkage/ butterfly valves at start up,if it kept the valves closed then it would flood out.

the throttle cable and linkage should be the ones that control the idle RPMs.
I believe the ECU will control the timing and if the timing is too far advanced the the RPM will go up. But make sure the throttle butterfly valves are closing off as they should before chasing other things

What are the butterfly valves? is that what i am holding down with my finger there? iv adjusted the throttle cabel, but the leveres that im holding down is the only thing that is adjusting the rpms, it should stay down towards the rpm idling screw?

[99yam40]

Look inside the carbs to see what those linkages are moving to control the amount of air let through the carbs.


They should be spring loaded to the closed position

[Eirikhau]

Aaaah! they are ?!

well, then im guessing that the spring is either gone or deffekt. because nothing is holding them down, they are just loose all the time...

so the choke is supose too pull them up when cold, and just release when down?

[TownsendsFJR1300]

The "butterflys"(the round things inside the throttle body that move) should close automatically on their own, that would be the idle position...

"Choke" position (or COLD START) adds fuel and raises the idle for a short period of time till the engine warms up.

[boscoe99]

Where in the hell is Rodbolt? He needs to put down the guns and bottles and give us a hand here.

I don't have any personal experience with the OP's particular model but the name Rube ****berg comes to mind when inspecting the parts catalog and service manual with respect to the fuel system. I suspect that Yamaha employed ole Rube to help them with the design and fabrication of their motors.

From what I can see this motor has a prime start device and a solenoid for choke plates. And the solenoid is activated when the starter is engaged, not when the key switch is pressed in or a choke toggle switch is activated. And then the solenoid power comes through some sort of thermoswitch.

I would have presumed that the thermoswitch is normally closed, allowing electrical power to flow to the solenoid when the motor is cold but preventing it when the motor is hot and choking is not needed, but the SM indicates it operates exactly like an over temperature thermoswitch. If the motor is cold and the switch is open then how can current get to the solenoid to activate it?

And what does the prime start do? It is not configured like a typical prime start component.

See wiring diagram below. Strange, just strange. Maybe Rodman can give us the theory of operation.