Help with Old Stihl 028

[ScipioUSA]

I may upgrade the points ignition in the future, but I just need to get it cutting first.

I only mention it because I once bought an 028 that wouldn't run for more than a couple seconds. Was acting like it was flooding out. Just needed a coil swap and ran great.

I know you have some air leaks to get fixed, but if after that you are still struggling, that's something to look into.

Best of luck getting it cleaned up and running again! They aren't the lightest or the fastest saws, but they have cut a lot of firewood....

 

[Michael In Tennessee]

Impulse line is easiest to replace if you remove the 4 isolators. As already mentioned a cheap pair of forceps makes it easier still. Isolators are a bit of a pain, but you only really need to remove the screws under the covers to get the saw to flex some.

Inspect the carb boot while you are there.

 

[4Liberty]

Thank you guys for the replies - I will be getting the impulse line tomorrow and starting work tomorrow evening. I will be watching those videos to get a feel for it, YouTube is such a good resource.

I may upgrade the points ignition in the future, but I just need to get it cutting first.

Dodgeman I mis-typed, it is the piston that is scored, thank you for the correction.

I have a big old 1960s SB air compressor that I use often…I always were eyepro because yes, blasting off the oil/sawdust mixture caked on the saw seems to just always find its way into your face.

This is where my chainsaw illness began. Once I figured out I could fix them it was a short trip to I can make this better.

 

[4Liberty]

Just to add some context, when I got the saw from the scrapyard it had a brand new (cheap) carb on it, along with a brand-new (cheap) fuel line and air filter + air filter housing. The previous owner obviously was having issues as well.

This week i'll run through everything short of pressure testing - if that does nothing i'll get a pressure test kit and check those seals.

Another thing, i've been pull-starting it without the bar attached and the plastics off. This week i'll put the plastics back on during testing to limit the airflow through the filter a bit.

Would having the bar/chain attached have any impact? My intuition is no, but just asking to be certain.


Thanks for this, i'll do this on all my 2-strokes instead of using standard starting fluid from now on.

That's brand new el-cheapo line I put on, the old one was essentially destroyed. I just took the foam fuel filter off to eliminate another variable. Ill probably buy some name-brand fuel lines as another poster recommended.

Good thought, i'll do that. Haven't thought of a pin-hole leak in that line. It was essentially brand-new (the line) when I got it at the scrapyard. I have another one from a carb kit.

I haven't checked - going to do this tonight. It does still have points, at least from what I remember when I took it mostly apart in May.

I appreciate the picture, i'm going to do this tonight.

It does seem like an air leak somewhere, what is this rubber boot you're talking about? Between the carb and the head there is a single (thin) gasket, no rubber boot. I'll try to take a photo tonight.

I will check this tonight.

After I exhaust all other options this week, i'll probably go get a pressure test kit. I am relatively determined to fix this saw.

Where is this boot? I only have a gasket between the carb and the head, that's how I got it at the scrapyard....would be interesting if it was simply missing a component. Compression is good, between 135-140 psi. Ill check out that pulse line.

As far as starting it without a bar and chain is not a problem with a stock saw. I would not be adjusting the high speed needle without it though. But just to get it started and running I don’t see a problem. Happy you found what appears to be one major problem you have one of the best firewood cutting saws there is.

 

[UOFan]

Afternoon everyone - installed the impulse line last night with the help of some needle-nose pliers, wasn't too bad. Got the saw to run (poorly) which I wholly owe to the advice given to me here, so thank you.

A few issues to address now. First and most importantly, I'm certain I have another air leak. With the choke off, the saw runs as if the throttle is wide open. If I choke the saw while it's running, RPMs significantly decrease, but not to a good idle speed. If I choke the saw AND cover the air filter with my hand it idles at a good RPM (similar to my MS271), but it is a surging idle. However, I am still very happy the saw runs. I had it running about 5 minutes to experiment with different levels of choke/airflow.

In order to get the saw going initially, I used a liberal amount of mix directly on the air filter. Not only will I be saving my piston/cylinder i've learned...but it's cheaper than ether which is a plus.

The other issue is that "off" doesn't work. Had to pull the plug wire to cut off the saw, as smothering the air filter simply dropped the RPM. I'm assuming it's the broken ground wire, which I will investigate today or tomorrow.

Next step for me is to fully check out the carb boot, as mentioned by many and most recently Michael. I did as good an inspection as possible while replacing the impulse line, but I need to verify before fully checking that off my list of potential air leaks. It's hard to see all sides of the boot.

Thanks all for the continued help.

 

[Michael In Tennessee]

View attachment 4692594

You have a metal bodied saw, mine is plastic, so its a little different. I think you just need to jumper from that existing lug to that threaded hole to its left. Mine goes from that bent spring at the start lever to that empty screw hole next to your existing grounding lug. That black wire on your start lever goes to the coil. That metal spring contacts that coil wire in the stop position and grounds the coil.

If I recall, the ground lug goes under the cover when installed. For testing purposes, you need that screw and the wire lug installed.

So, have you messed with jet adjustment yet? That might solve your poor running. I'd do that first. Get the saw to run, however badly. Use the idle speed screw to get it to run hands free. Adjust the idle jet in or out to achieve best running. If it picks up revs, turn down the idle speed as you work on the idle jet. set the idle to max speed, then richen until it just slows down a touch. You want a slightly rich mixture. Now work on the high speed jet. Go full throttle and adjust the high speed jet for best running then, again, richen just a tad. You can do an initial setting of the high speed without the chain, but you want to readjust with the chain on. Probably mess with the high speed some when cutting wood. Make a cut, adjust 1/4 turn, try again for best effect.