Stubborn Chainsaw Running Issue

[Muddy42]

Yes I think it is an air leak somewhere that I just havn’t found yet. 

[adw]

I am not convinced about an air leak, these machines eat ignition units, I have fitted plenty, I would just pull the whole thing apart as it does not take long, change the small sealing strips between cylinder and crankcase, belt and braces use some instant gasket as well, a couple of crank seals and rebuild, it’s pointless just messing about as you are not getting anywhere, they have a governed ignition so do sound funny at full revs and are not easy to get right, you cannot taco them at full revs because the ignition governor upsets the taco.

[pleasant]

1 minute ago, adw said:

I am not convinced about an air leak, these machines eat ignition units, I have fitted plenty, I would just pull the whole thing apart as it does not take long, change the small sealing strips between cylinder and crankcase, belt and braces use some instant gasket as well, a couple of crank seals and rebuild, it’s pointless just messing about as you are not getting anywhere, they have a governed ignition so do sound funny at full revs and are not easy to get right, you cannot taco them at full revs because the ignition governor upsets the taco.

A fair point

[Muddy42]

20 minutes ago, adw said:

I am not convinced about an air leak, these machines eat ignition units, I have fitted plenty, I would just pull the whole thing apart as it does not take long, change the small sealing strips between cylinder and crankcase, belt and braces use some instant gasket as well, a couple of crank seals and rebuild, it’s pointless just messing about as you are not getting anywhere, they have a governed ignition so do sound funny at full revs and are not easy to get right, you cannot taco them at full revs because the ignition governor upsets the taco.

Thanks. My friend suspected an ignition unit aswell and I've given him the OK to take everything apart. Let’s see if he can fix it.🤞

[adw]

Just a word of advise, do not fit a non original unit, and make sure you get the correct unit for it, there are more than one, to make sure you need to remove the flywheel, on the underside will be a part number, go to a parts list that shows the part number and use the unit from that list.

[spudulike]

Perhaps get a pic or two up so ADW can advise, he knows a little bit about Husqvarnas and ignition units cost a bit so an incorrect one would be bad news. 

I second not using aftermarket ignition units. At best they can be iffy!

[Muddy42]

Thanks both

[pleasant]

17 hours ago, Muddy42 said:

Thanks both

'both' ......so just the two then?

Edited December 24, 2022 by pleasant

[Muddy42]

15 hours ago, pleasant said:

'both' ......so just the two then?

Apologies, thanks to ALL who have posted on this thread over the past few months.

[Muddy42]

Right so the problem is now fixed and the saw is running.

Sometimes its the silly things right? But I would’ve helped if I had more pleasure and electrical testing kit (like my friend does).

 

so the new replacement carb that I had bought turned out to be leaky from the start - cr@ppy knock off ebay rubbish!

 

so in order what I think happened was.

 

1. I replaced the carb, no noticeable difference in the air leak. I assumed it would be best to continue using the new carb, as it should be fault free.

 

2. I replaced intake boot. I think this was where the leak was all along, but I couldn’t tell because the carb was bad.

 

3. my friend pressure tested both carbs, put the old one back and checked the quality of the spark. The saw ran fine so he re-tuned. I used a tank of fuel to cut some logs. All good.

 

Thanks again for the help.