Oil pump on 020 stihl

Hyway decompression valve fits Stihl TS400, TS410 ...

https://www.amazon.ca > Hyway-decompression-valve-...
Hyway brand decompression valve. Fits: Stihl TS400, TS410, TS420, TS460, TS700, TS800 cut off saws. Replaces OEM part: 4223 020 9400 ...


Here is your MANUAL. Page 39 says not all have a decompression lever. Perhaps you can retrofit?

STIHL TS 410, 420

https://www.stihlusa.com > instructionmanuals > stihl...
PDF
TS 410, TS 420. English. 1. This instruction manual ... Contact your STIHL dealer or the STIHL ... manual. WARNING. Because this cut-off machine is a high-.


..

20 thousandths of an inch .020

Model Profile: 028 AV

http://www.acresinternet.com > cscc.nsf > OpenDocument
STIHL ANDREAS MASCHINENFABRIK. STUTTGART, GERMANY ... SPARK PLUG GAP: 0.51mm (0.020 in.) CRANKSHAFT MAIN BEARINGS: ... Stihl 028AV.prn.pdf. SERVICE

check Stihl Decompression Valve - 4238 020 9400
https://www.diyspareparts.com/parts/stihl/decompression-valve-4238-020-9400/

I'm almost sure you have to remove the oil tank and then the oiler

It is possible your flywheel has lost it's magnet strength, if you noticed it turn a blue. Can take off flywheel and replace with a good one. Or you can play with the gap on the magneto/coil, and insert a piece of paper between the coil and the flywheel magnets, to set for air gap.

the air gap is about a business card thick and the plug gap is .020. Stihl has a special tool to measure exact air gaps so the business card is close

If you need further help, I’m available over the phone at https://www.6ya.com/expert/kelly_69a0cf1b13789df1

The filter in the oil tank may need to be cleaned.But you will most likely will have to replace the oil pump and it will have to be done at a stihl dealer. It requires special tools to remove and replace. George

ignition timing control by pcm.if you try adjusting timing by turning cam shaft you going to damage engine valves and pistons you are going to throw off valve timing when you turn camshaft.

take the carby in for overhaul and new diaphragm kit fitted
the main diaphragm is hard and not sealing on the holes so it is not pumping fuel
40: 1 or 50: 1 is alright and the gap is .020-.025"

why I say that is that stihl use an oil that mixes as 50:1 but it is suitable for the full range of ratios in the stihl range of engines
makes no difference what brand of engine , the ratio is to ensure enough oil to lubricate the bearings and cylinders

This is an international collection of chainsaw enthusiasts with a few 2-cycle mechanics thrown in for good measure.
ArboristSite.com Chainsaw thread (free to join)
http://www.arboristsite.com/forumdisplay.php?f=9

This thread is discussing an oil leak on a Stihl 015; join in.
http://www.arboristsite.com/showthread.php?t=114962&highlight=stihl+015+oil
HTH
Lou