Can someone explain a Thermostart

[gt14]

Can someone explain a Thermostart. I have a YM165D and it has a thermostart. There is a small bowl that feeds into the air intake. What do I do to use this.

 

[Eddie]

The thermostart element has a heating element in it like a cigarette lighter. The small reservoir has diesel in it. When you turn the switch to the thermostart position the element gets hot and diesel drips on it causing a small fire which heats the air in the intake manifold makes it start easier. I just had to replace my thermostart element because the heating element was burned out.

If I'm not correct someone will help straighten us out.

 

[Eddie]

Here is a picture of the Thermostart that I had to replace in my 2020.

 

[DrewYM226D]

This is copied word for word from my YM226D factory manual (anything in parenthesis added by me for clarification purposes):

Thermostart Device
With a cold engine and at ambient temperature below 32°F (0°C), operate the thermostart device as follows:
1. Pull throttle lever fully rearward. (This is the engine-kill position on the YM226D).
2. Pull decompression lever for easy engine cranking. (Are you in neutral)?
3. Crank engine 5 to 10 seconds until oil pressure indicator lamp stops glowing. If the lamp does not stop glowing for first attempt, try again after waiting one minute.
4. Place throttle lever in fully forward position (this is full throttle on this model).
5. Turn key counterclockwise and hold it there 10 to 15 seconds. An electric thermostart plug ignites a small amount of fuel in the intake manifold.
6. Pull decompression lever and depress clutch pedal.
7. Quickly turn key clockwise and start engine.
8. As soon as engine starts, turn key back to thermostart position and pull throttle lever about halfway back. Hold key in this position until engine runs smoothly and then turn to “ON” position. If engine does not start within 10 seconds, turn key to “OFF” position and wait at least one minute before trying again.

The book also recommends trying a coolant/block heater for temperatures below 10°F (-12°C).

I can't vouch for any other Yanmar tractor, but this may help someone understand how to use it and what it does on the YM226D. By the way, it is below 20°F here in Pittsburgh Steeler Counrty right now and it started right up using this method. Good luck!!!!

 

[gt14]

This is copied word for word from my YM226D factory manual (anything in parenthesis added by me for clarification purposes):

Thermostart Device
With a cold engine and at ambient temperature below 32°F (0°C), operate the thermostart device as follows:
1. Pull throttle lever fully rearward. (This is the engine-kill position on the YM226D).
2. Pull decompression lever for easy engine cranking. (Are you in neutral)?
3. Crank engine 5 to 10 seconds until oil pressure indicator lamp stops glowing. If the lamp does not stop glowing for first attempt, try again after waiting one minute.
4. Place throttle lever in fully forward position (this is full throttle on this model).
5. Turn key counterclockwise and hold it there 10 to 15 seconds. An electric thermostart plug ignites a small amount of fuel in the intake manifold.
6. Pull decompression lever and depress clutch pedal.
7. Quickly turn key clockwise and start engine.
8. As soon as engine starts, turn key back to thermostart position and pull throttle lever about halfway back. Hold key in this position until engine runs smoothly and then turn to “ON” position. If engine does not start within 10 seconds, turn key to “OFF” position and wait at least one minute before trying again.

The book also recommends trying a coolant/block heater for temperatures below 10°F (-12°C).

I can't vouch for any other Yanmar tractor, but this may help someone understand how to use it and what it does on the YM226D. By the way, it is below 20°F here in Pittsburgh Steeler Counrty right now and it started right up using this method. Good luck!!!!

Thank you for the great explanation.

 

[normde2001]

"6. Pull decompression lever and depress clutch pedal.
7. Quickly turn key clockwise and start engine."

I'm betting the engine won't start with the decompression lever pulled .

 

[kmosabe]

"6. Pull decompression lever and depress clutch pedal.
7. Quickly turn key clockwise and start engine."

I'm betting the engine won't start with the decompression lever pulled .

I agree with Norm, I have tried this step, and it does not start this way, any others?

 

[runningbird]

I'd have to agree, it won't start with the decompresion open. also believe or not it will not start w/o a battery when one of your boys takes it for his car.

 

[California]

This is copied word for word from my YM226D factory manual ... Good luck!!!!

Does that model have the key on the left? Holding the key and simultaneously pulling the throttle back from wide open would require a contortionist on mine!

But I learned something here. They recommend turn the key left and continue heating the intake with the thermostart after the engine fires, until it is running smoothly. I don't recall seeing that before or maybe I never noticed.

 

[DrewYM226D]

"6. Pull decompression lever and depress clutch pedal.
7. Quickly turn key clockwise and start engine."

Silly me, since step seven said "and start engine", I just assumed I was supposed to also release the decompression lever as usual. But I see your point: If you don't release the lever, it won't start!

You'll also notice steps two and three don't address pushing in the clutch or making sure you are in neutral before cranking with the lever pulled. I'm pretty sure that would be a good idea though!

"Does that model have the key on the left? Holding the key and simultaneously pulling the throttle back from wide open would require a contortionist on mine!"

No, the 226 has the key on the right. Just move fast and stretch your arm or as soon as it starts, move the left hand to the key and the right hand to the throttle.