I have a Stihl leaf blower, model BG 55- Z. It was running fine, ran out of gas, refilled it, would not start. Replaced plug (even though plug looked good). Tested spark, good. Tried a small squirt of starter fluid, nothing. Rebuilt carb, noticed nothing damaged, and replaced fuel filter. Still no start. Removed muffler, soaked in desolvant over night even though it looked OK. Looked at piston through exhaust port, piston and rings look very good. Reinstall muffler, still no start.
Compression test 75. I understand it should be between 90 and 110.
Would a low compression test of 75 cause the engine to not fire at all?
Is it likely that the engine would go from running well one minute to not starting at all the next as a result of some compression issue?
#2
RDA.Lawns
If it doesn't have enough compression its not going to run. Its possible the ring broke or the piston is scored bad.
Yes.
Lumps of carbon can fall off the exhaust port and score the bore in a single pull sufficiently to stop the engine starting.
Stihls are usually a little better as most use 2 rings.
Pull off the muffler and have a look at the bore & piston.
If the bore is relatively clean then you might get away with a new set of rings.
If it is scored then it is new piston & barrel time.
Aftermarket ones are usually fine if bought from a real dealer.
A lot of what you see online are the parts that Stihls QC department rejected.
I have trashed about 30 Husqvqrna chainsaws in the past few years because a lump of the chrome plate inside the bore about the size of a pearl headed pin has flaked off.
Spin them fast enough & they will start & run fine although a bit smokey but with the easy start feature you can not start them.
Thus I have been advising all my customers to avoid Husqvarna chainsaws like the plague as this is a manufacturing defect but it does not show up till they are out of warranty & Husqvarna refuses to admit liability.
