The chainsaw has been excellent and reliable. Suddenly got very blue smoke and would not restart. Have always run it probably slightly too rich with oil (40-1) I assumed it was a carburettor problem so replaced it with a new one. I removed the exhaust box which had oil inside. Still would not start. Stripped it down completely. (with the help of YouTube) The piston and crank were fine. The crank seals were fine. Top of piston was carboned up so cleaned it up and rebuilt it. Its getting fuel through as the plug is wet. There is a good spark. What am I missing ???
Husqvarna 445 xTorq does not start
- Thread starter PhilW
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- chainsaw questions
Spark, correct fuel air mix entering the combustion area, compression and correct timing is all it takes for a chainsaw to run.
Photos of said good engine components would have been nice.
Running rich or tuned rich is not a result of oil ratio in the mix, it is in the carb tuning.
Heavy carbon build up, oil in mufflers usually means excessive use of oil, cheaper high ash oils and excessive unburned fuel load.
Could be as simple as a new correct spark plug needed- could be a new piston and ring needed, could be a shorn flywheel key.
Pressure and vacuum test would be my first port of call.
Photos of said good engine components would have been nice.
Running rich or tuned rich is not a result of oil ratio in the mix, it is in the carb tuning.
Heavy carbon build up, oil in mufflers usually means excessive use of oil, cheaper high ash oils and excessive unburned fuel load.
Could be as simple as a new correct spark plug needed- could be a new piston and ring needed, could be a shorn flywheel key.
Pressure and vacuum test would be my first port of call.
Thank You for the comments. The chainsaw was running normally and then suddenly there was blue smoke at the exhaust followed by cutting out. So not a gradual deterioration. My concern initially was that running slightly oil rich was the possibility of oil build up in the carb possibly damaging a diaphragm or something. I partially stripped the carb and examined a diaphragm but couldnt see anything wrong but was told they can deteriorate over time. Nevertheless I have replaced the whole carburettor as not expensive. The spark plug has been replaced. The fan/flywheel has been removed and the key is integral with the casting and in good condition. The ignition pick up gap I measured at 0.035" and was reset to this. The crank/piston is in good condition, I just removed some carbon build up from the top of the piston- no scoring or wear in the bore and no play in any bearings giving good compression although I havnt done a compression test. I will do this but maybe a vac test will show up something. Thank You Phil