90TLRC cold start choke question

[fastback4]

How does my engine, 2003 90TLRC, know when to use the choke start during the day of fishing, especially the first start up. I push the primer bulb till hard, push the neutral engage button at the throttle lever and nudge the throttle open some and turn the key. My motor will not start right away so I push in the key which I assume engages the choke. Eventually my motor starts and runs like a cold 2 stroke should but is this the correct procedure or should I increase the throttle position?

[Jason2tpa]

Although I'm sure Yam has a standard cold engine starting procedure, the thing of it is every engine has its quirks. Pushing the key in chokes the carbs, allowing a richer mix to help ignition. Opening up the throttle allows more fuel into the already rich (choked) mix. Sometimes, and some engines, require both to cold start the engine. Others only require the choke.

With that said, the only procedure I would recommend to you is choking the engine first. Give it a couple key turns. If it doesn't turn over, then add a little throttle.

[Rlilleaas]

Most likely some debris in your auto primer (behind the oil tank). No choke will be enabled by pushing the key in on these as far as I am aware. Do not use the manual throttle as suggested.

[boscoe99]

A 90TLRC does not use a choke plate to enrichen the fuel mixture for a cold start. Pushing in the key to use the press-to-choke function does nothing. The motor has what Yamaha refers to as a Prime Start to add extra fuel during a cold start condition. It is all automatic.

If you want to know more about the inner workings of the PS device holler.

In the mean time, try putting the throttle handle in different positions to see if one works better than the others. The owner's manual for your model suggests putting the throttle handle in the neutral position. Maybe you are opening the throttle a bit too much. See page 3-11.

http://www.yamaha-motor.com/assets/s...-04-93_420.pdf

Now I will add that Yamaha has been forced to reduce emissions on their motors such that some run so lean that they can be very difficult to start. Not like the old days.

[Rlilleaas]

The prime start is automatic but could be blocked - I have the same "symptoms" on mine. The auto prime is a solenoid/needle with tight passages. Be careful if you open it so you do not break the bolts on top. If I recall correctly it operates on a 5V signal.

You should have a red "handle" on it (visible near the oil container). It is normally in "normal" - try to flip it over to emergency - and see if it fires up quicker then (switch it back after it has started). If it improves...I would say you are close to your problem since this puts the "needle" to fully open position.

Could also be som blockages in the carbs, but I would investigate the auto prime first.

What is the idle rpm when it has settled down?

[boscoe99]

It is all in the owner's manual.

After all else fails, try following in the directions.

[throrope]

It is all in the owner's manual.

After all else fails, try following in the directions.

I'm not sure where I read it, but I recall directions saying to run the starting motor in 5 second intervals/bursts until start. That does it for me without nudging the throttle and yes, as also written it will run a bit rough when cold and settle down as it warms.

boscoe99 is correct on the Prime Start. I do recall a diaphragm on ours that if damaged could cause issue.

Is this new to you? If not, do you notice a change? If so, has it sat?

When ours was new to us, I thought I had to use the red emergency enrichment lever and monkey with the throttle until I understood our carbs and fuel system were damaged and crapped by old ethanol gas. It didn't run well until a Yamaha tech went through the carbs and I replaced the entire upstream fuel system about four years ago. I'll add my usual success of removing all fuel between trips. No gas for me means no gas to go bad. Haven't touched it since.

[99yam40]

The prime start is automatic but could be blocked - I have the same "symptoms" on mine. The auto prime is a solenoid/needle with tight passages. Be careful if you open it so you do not break the bolts on top. If I recall correctly it operates on a 5V signal.

You should have a red "handle" on it (visible near the oil container). It is normally in "normal" - try to flip it over to emergency - and see if it fires up quicker then (switch it back after it has started). If it improves...I would say you are close to your problem since this puts the "needle" to fully open position.

Could also be som blockages in the carbs, but I would investigate the auto prime first.

What is the idle rpm when it has settled down?

No 5 v on prime start system, uses output of the lighting coil while motor is running to heat up wax pellet to push the needle closed.
Red lever does not move the needle, just opens up/closes off different passages for fuel.

Owners manual has the starting procedure for your motor.
should be leave throttle alone and turn key to start for a few seconds, leave off for a few seconds and repeat until motor starts
usually if everything is working properly it should start in 3 or 4 tries when cold if carbs are full of fuel(using the primer bulb).
advancing the throttle too far can cancel out some of the programming for prime start ( timing, fast idle for warm up,etc)

[boscoe99]

No sure if your model motor uses an accelerator pump in the carburetor or not. You might try rapidly pumping the throttle handle several times prior to a cold start. It might supply just a bit of extra gasoline that can help to get the motor started. Pump once rapidly. Return to the idle position. Wait a second and then pump again. Use the neutral button so the motor does not try and shift into gear.

Try it and let us know if this helps. If starting with the throttle handle in the position suggested by the owner's manual does not help.

[rodbolt17]

no accelerator pumps.
moving the throttle only wears out the cable.

IF and ONLY if the engine is running correctly simply prime the carbs and turn the key.