Stihl 045AV Cutting Out

[WelshMan]

I've just bought a Stihl 045AV Electronic, sold as "spares or repair". The spark-plug boot and on-off switch were both missing.

 

To my surprise I got it working this morning with a new plug and boot. I'd pretty much expected beforehand that it would have ignition coil problems.

 

It starts and runs but has a habit of cutting out. That saves worrying about the stop switch . My initial thought is that it's probably not the coil or ignition because it needs the choke to get it started again. That's even when it's really hot.

 

My thinking is that it's the carburettor, but I'm really not familiar with carbs or ignition systems.

 

I've ordered a service manual.

 

Any ideas?

 

Also, are the parts for an 045AV pretty much the same as for an 045?

[wisecobandit]

Sounds a bit carb related by what you say.

I would strip and clean it and put a new diaphragm kit in it as a matter off course given the age of the saw. Maybe something as simple as the little mesh filter blocking up inside the carb. Would certainly be my first port of call.

[Rich2484]

What he said.

 

You could also have an air leak in the saw. This would contribute to needing the choke but normally you need to choke at any time for this to be the case.

 

Sound alike lack of fuel. What colour is the spark plug?

[spudulike]

On an old saw like this it would be worth replacing the fuel line and impulse line if itis a separate one.

 

It sounds carb related as others have said, you can get resins and grunge forming in saws that have sat for a while and fuel filters can get glued up as well.

 

It may be the carb needs to be adjusted and it is possible the L screw just needs undoing 1/4 turn and the idle adjusted to run a little faster - the diaphragms can change shape on saws left for a while and mess the mix up.

 

When adjusting these older carbs, changing the L screw can often change the setting of the H circuit so if you open the L screw up, you may need to adjust the H screw back in.

 

Using the choke when starting a hot saw point towards the saw running a bit lean on the L screw - it may be the fuel tank breather is blocked - try loosening the fuel cap when it stops again and then starting the saw with no choke.

 

Another possible is that the "fast idle" setting on the saw isn't working correctly - I don't know if this is a push button type or operates off the choke on this saw but is another possibillity!

 

Good luck

[WelshMan]

Thanks for all the replies. That's really helpful.

 

The old plug was dark grey/ nearly black but not oily. The saw hadn't been used for at least 3 years.

 

I'll start looking at the fuel system and carburettor once my service manual arrives.