TS400 Saw - non runner

[Monkeynuts]

Hi all,

I have just bought a non runner TS400 and i'm looking for some advice.

The problem is as follows: -

When trying to start it, it fires and then dies. The ignition is only for a slight moment with a slight puff of smoke from the exhaust. If the choke is applied, you dont even get the slight firing.

It has had a new piston and rings, plug, fuel and has great compression. A small amount of fuel added to the removed plug hole results in exactly the same result, a slight ignition with no sustained running.

It does not seem to be fuel as the plug is damp when removed, could it be a weak ignition coil?

Any suggestions welcome.

 

[EngineMan]

"could it be a weak ignition coil?" Yes test the coil.
A quick test with the multimeter if there is continuity between the low tension terminal (which is used to switch off the engine) and earth.
If there is replace ignition module.

 

[Monkeynuts]

Checked for continuity and there was none.

I'll have to take the risk and buy a new coil - can't see what else it could be?

 

[Rivets]

Make sure that the screen in the carb is not plugged. Have found that most Stihl problems are fuel related and not ignition. Have you rebuilt the carb and checked all fuel lines for pinching or cracks?

 

[Monkeynuts]

I gave it a quick look over and found nothing out of the ordinary.

What makes me think ignition is the fact of adding fuel to the spark plug hole results in exactly the same problem. I would of thought it would have ticked over for even a fraction longer after doing this?

 

[Rivets]

If you feel it is the coil go for it. I just don't like replacing parts until I know what's wrong. If it fires once and then quits, I would suspect that the coil is good. Normally a coil will not fire at all or quit after it heats up. If you take the plug out and ground it, do you get a continuos spark? Remember, you need continous spark, continous fuel, and compression to make it run. Just my thoughts, but who am I?

 

[Monkeynuts]

No mate thanks for your thoughts.

I'll investigate a bit more and will hopefully respond to what the fault was soon!

 

[EngineMan]

Checked for continuity and there was none.

I'll have to take the risk and buy a new coil - can't see what else it could be?

If it was me, that would be the path I would go, just come back and let us know.

 

[Monkeynuts]

Update for you all.

I fitted a new coil and it fired into life first pull.

Strange really as the spark from the old coil was bright and regular. Must have been breaking down under load.

Thanks for all the advice :thumbsup:

 

[EngineMan]

Update for you all.

I fitted a new coil and it fired into life first pull.

Strange really as the spark from the old coil was bright and regular. Must have been breaking down under load.

Thanks for all the advice :thumbsup:

unfortunately I have seen it so many times over the years.. and I have tested many of them, well done to you happy you have it up and running again...:thumbsup: