Stihl 026

[Jimmythenose]

Hey guys!

I bought an old 026 to play around with learning to fix and possibly port as I'd be too scared to mess with my ms241 or 562xp, and I'm looking for a little advice on getting it running.

So far I've checked the piston through the exhaust and intake and it looks good, I've checked that it has spark, the fuel line is clear the fuel filter looks new, I took the covers off the carb and the diaphragms/gaskets seem pretty new, and the saw seems to have decent compression.

I tried to start the saw and I think I flooded it, I tried pulling the plug and pulling the cord a few times to clear it out, then tried pulling the cord about 30 times with the plug in, with the choke in run position, and full throttle, and even in this condition there is still fuel blowing out the exhaust.

Is the saw likely still flooded? Or could this possibly be some issue with the carb? What should I try next?

Thanks!

 

[Mad Professor]

It's flooded if fuel is "blowing out the exhaust".

You may have fuel pooled in the crankcase. Pull the plug and pull it over until you are sure it's clear. Then clean the plug and see if it will at least pop with a clean dry plug.

Carb issue could be metering valve/seat, debris in the seat, incorrect metering adjustment.

See if it will pop before you are chasing your tail and tearing into it.

 

[John Lyngdal]

Set the saw to no choke. Pull the spark plug and blow out the cylinder with compressed air. Pull the cord several times and repeat the blow out.
Run this cycle several times to clear the crankcase of excess fuel. Install and connect the spark plug, and put a small amount of fuel down the carburetor throat and then see if you can get it to pop on prime.

 

[Jimmythenose]

So I pulled the carb and plug, pulled the engine over quite a few times and blew some compressed air in till it stopped smelling of fuel. I dried the plug, reinstalled it and the carb and pulled it a few times with no choke and WOT, it sounded the closest it has to popping, and I could smell combustion for a couple of pulls, but after about 10 pulls I removed the plug and it was wet again. Also on the last few pulls it definitely looked like vaporized fuel was coming back out through the air filter.

The saw is definitely going to need a helicoil in the plug hole, and depending on what the shop charges for that this project could be over already haha, if I get them to do it I may have them test the carb at the same time.

 

[John Lyngdal]

Repeat as before, but remove the fuel line from the carburetor, then see if you can get the engine to pop.
I've had good results with Meteor piston and cylinder kits for rebuilding 026 saws.

 

[cookies]

Probably needs rings, low vacuum causes the fuel to be sucked in as a liquid instead of as a vaporized droplet, with it trying to be started over and over soaking the plug this likely has fouled it out. Start by getting a compression tester and making sure its over 135 psi. If its low and the cylinder/piston look good stick a set of rings into it.

 

[Mad Professor]

Do the comp test. Don't just dry the plug clean it. A glaze of crap will give you a weak spark.

If you are going to fix the plug threads pull the cylinder. Then you can check piston for wear and put a set of rings in, and no shavings from helicoil install gets inside. Seals come with a gasket set, think about those too if you are going to keep the saw.

 

[Jimmythenose]

Well the shop wanted more than I was willing to spend to do the helicoil, so if I do it, I'll do it myself, probably with this kit.

https://www.amazon.ca/Helicoil-5334-14-Thread-Thread-Repair/dp/B0002SRF4O/ref=asc_df_B0002SRF4O/
I've pulled the cylinder and taken some pictures, perhaps it isn't in as good of shape as I thought. What do you guys think?

If I move forward I'll probably do new rings and a carb kit at the least. I probably should have cleaned it better before removing the cylinder, maybe I should take the case apart and give everything a thorough cleaning before assembly.

 

[cookies]

In the 4th picture you can see the piston crown edge chipped off and likely caused that scoring and second ring land damage. Probably resulted from the crazy carbon build up or it ingested trash. It dosent look ruined but I'd clean up that cylinder and stick a new oem piston in after tearing it down to inspect the bottom end + clean it up.

 

[John Lyngdal]

The cylinder bore looks reasonable to me as well. A new piston and a spark plug hole repair and you should have a running saw.

In the 4th picture you can see the piston crown edge chipped off and likely caused that scoring and second ring land damage probably from the crazy carbon build up or it ingested trash. It dosent look ruined but I'd clean up that cylinder and stick a new oem one in after tearing it down to inspect the bottom end + clean it up.

 

[Totembear]

Have you done a preesure/vac test yet? If not you might be chasing ghosts. Get that cylinder fixed, put a piston in it and p&v test it. If its tight then try looking at the carb.

 

[Mad Professor]

Have you done a preesure/vac test yet? If not you might be chasing ghosts. Get that cylinder fixed, put a piston in it and p&v test it. If its tight then try looking at the carb.

Gasket set comes with seals. If you are doing a piston on a 30 year old saw replacing those are a no brainer. That's one of the reasons I also take off clutch/flywheel, and clean up those areas, BEFORE taking off P/C.

Pres/vac will tell if impulse/intake also might have a leak.

 

[link]

my ms241 or 562xp

 

[link]

I've pulled the cylinder and taken some pictures, perhaps it isn't in as good of shape as I thought. What do you guys think?

"If I move forward I'll probably do new rings and a carb kit at the least. I probably should have cleaned it better before removing the cylinder, maybe I should take the case apart and give everything a thorough cleaning before assembly." Yes sir, yes!

Cylinder and piston looks good to me, but sir - you gotta take that saw apart and properly clean it all up before you start working on it. Look out for all rubber parts because they desintigrate over time and might be surprisingly affordable to replace with new ones when you're at it - crankshaft seal and gas tubes being some of my favorites.

 

[cookies]

This is the chipping im talking about
https://prnt.sc/a4bJwSCgimLT

 

[Backyard Lumberjack]

hello Jn -

your 026 project sounds interesting. i like the 026. i have one, still close to NIB, and bought new. runs like new still, too! a lot of good advice in this thread. when i start mine, i get no blow by of fuel out carb or exh. i see ur piston, but to me, an engine builder, i do not see enough side wall/ringland areas damage to prevent it from running. if that is all the piston damage the saw has, i would break the edges and run it. new rings? be sure u fit them properly! some bore wear, but oil grooves on piston side more or less still there. no doubt about it, all things aside u do have to have high enuff compression. too bad u pulled that dirty cyl. i like the tech advice to pull fuel line and dry it all out and dribble some fuel in thru carb... and if u have ignition timed correctly, if u have compression up there, and spark... you should be able to get it to pop-off consistently. is the plug hole threads stripped out? badly worn out? torn out? what condition? cannot seat the plug? if everything is set right, and if u get the new rings on correctly and the cyl back together and it is ready to go, and choke is set for cold start as manual suggests then it should fire off and try to idle, then run out of prime fuel. if it was mine, i would not chase it and try to get to throttle. if everything is set right, u wont need to to test at this level. mine once did give me some starting trouble. it was not being user-friendly, but would fire up, but only idle. bar/chain off. touch throttle, it would just die. consistently. so i did a new fuel diaphragm etc to carb and it fired right up and ran great again!

it goes without saying, that any work on your saw should be (must) done with everything spotlessly clean! my Dad was an ace-wrench... trained A/P, recip/jet/turbine etc and he had a saying...

"when it comes to engines, cleanliness is close to Godliness!"

hope your project saw will soon be running...

 

[pioneerguy600]

Well the shop wanted more than I was willing to spend to do the helicoil, so if I do it, I'll do it myself, probably with this kit.

https://www.amazon.ca/Helicoil-5334-14-Thread-Thread-Repair/dp/B0002SRF4O/ref=asc_df_B0002SRF4O/
I've pulled the cylinder and taken some pictures, perhaps it isn't in as good of shape as I thought. What do you guys think?

If I move forward I'll probably do new rings and a carb kit at the least. I probably should have cleaned it better before removing the cylinder, maybe I should take the case apart and give everything a thorough cleaning before assembly.

Jimmy, that piston looks too shiny to me, when that polished they are often badly worn on the skirt. can you get a pic of the bottom of the piston? That would tell me how thin the skirts are getting, when the skirts wear excessively the piston rocks in the bore and compression drops. Doy you know if the cylinder is a 44mm or a 44.7 mm variety?

 

[Jimmythenose]

Jimmy, that piston looks too shiny to me, when that polished they are often badly worn on the skirt. can you get a pic of the bottom of the piston? That would tell me how thin the skirts are getting, when the skirts wear excessively the piston rocks in the bore and compression drops. Doy you know if the cylinder is a 44mm or a 44.7 mm variety?

Its a 44mm, but it'll be needing a new cylinder regardless, so I'll probably get a p&c kit. With the way things are going this is looking like a winter project now. Dealing with the damage from Fiona has led me to getting a 592xp so my CAD is satiated for the moment haha

 

[pioneerguy600]

Its a 44mm, but it'll be needing a new cylinder regardless, so I'll probably get a p&c kit. With the way things are going this is looking like a winter project now. Dealing with the damage from Fiona has led me to getting a 592xp so my CAD is satiated for the moment haha

A new saw will calm the CAD nerves often to the point old saws are forgotten. The Island sure got hit hard, we were very lucky on this side of N.S. that it mostly missed us but still plenty of downed trees to deal with.