Chainsaw won't stay running

[jonp]

Managed to score the cylinder by mistakingly running straight gas through my 20yr old Husky 41. I bought a new cylinder and piston with rings and put on a new carb, fuel line, filter and bearings while I was at it. I used Versachem High Temp Red RTV to seal the bottom onto the cylinder. All looked good but it wouldn't start and stay running. First time I could get it going with starting fluid and then revving while playing with the choke. I thought this indicated an air leak so took it apart, scraped off the old gasket stuff and put on new then resealed. Would not even run. I took the carb apart and blew it out then put it back together and with a little starting fluid will run but dies. Won't stay running.

Any ideas? I don't think I'm putting anymore money into this one as I bought a new Jonsered cs2152c a sawshop had on the shelf. I just want a saw to leave at camp and put my Chinese one out there for that but would like to get this old saw running. I've cut a ton of wood with it.

[Bazoo]

Sounds like a cracked fuel line. Since you replaced them, any chance you damaged the new line?

I had similar symptoms except it wouldn't do any more than start, rev and die, on a craftsman and I'd reversed the fuel/return lines. Looked backwards when it was correct.

Exhaust screen blockage will cause the symptoms you have.

[jonp]

New line and I watched while cranking to make sure fuel was running through it. When I took it apart I cleaned everything including the case. Took it down to every part. looks brand new except for the not running part

[Hogtamer]

Does it have the push bulb to move gas? If so that's what I'd replace.

[dkf]

If the carburetor is fed by a pulse port from the crankcase make sure the hole is not blocked. Fresh fuel? Carburetor need adjusted? Spark Plug new? I can tell in my saws when the fuel starts going south, first thing to suffer is the idle quality and it does not want to idle long. Harder to start also. Todays fuel does not last like it used to, even pure gas with a stabilizer.

Oh and don't use starting fluid on it, unless you want another scored cylinder. There is no lubrication with starting fluid and the lubrication that is there is washed away by the starting fluid. When the motor is lubricated by oil mixed in the fuel it is an issue.

[jonp]

No push bulb, fuel is new. Carbs adjusted to basic setting to start. One turn off.

[5Shot]

Try the chainsaw forum over on Arboristsite - tons of guys on there that know a lot about what makes a saw tick.

[Markopolo]

i think there is an air leak between the saw cylinder and the carb... i had a heck of a time getting mine re-sealed up when I rebuit the top end. its that dang spacer thingy. its suckin air...

if you wanna know forsure, dump the gas out of it... spray starting fluid around that spacer thing up to the cylinder. and quickly try to start the saw... dont let it run.. you just wanna see if it wants to kick off... be sure to choke it...

hope that helps...

marko

[Bazoo]

Perhaps a bad decompression valve?

[bdicki]

I don't use starting fluid, use carb cleaner instead.

[atr]

is the spark good?
some plugs will show spark when removed and then grounded against the case, BUT that same plug might be breaking down under compression....trust me I've had this happen..
I would at least replace the spark plug.
note: I have found spark plug manufactured in China to have a very short useful life.
good luck
atr

[Winger Ed.]

I've had fits with them and it was a deal where nothing was wrong- it just wouldn't run..... until I put a brand new plug in it.

[Finster101]

If it ran fine before with the old carb, put it back on and try it.

[jcren]

I use a turn and a half for a baseline on idle circuit. Not sure on that saw, but most small carbs have idle air bleeds ( emulsion tubes ) for low speed which means close it for richer and open for leaner. Otherwise, air leak on the intake manifold sounds likely.

[Lloyd Smale]

did you by a new factory carb or an ebay knock off. I bought a knock off for my Polaris sportsmen because they were 50 bucks and a new Polaris carb was over 200. What I did was waste 50 bucks.

If it ran fine before with the old carb, put it back on and try it.

[metricmonkeywrench]

Just has 2 similar scenarios, one with a Weed Wacker and the other with a saw. In both cases it was carb related.

On the fist one I "lost" the carb to adaptor/cylinder interface seal during a carb replacement and didn't notice it missing. It served a 2 fold purpose, 1st to seal the fuel/air into the combustion chamber and the second to supply the crankcase pulse to the carb fuel pump. I could prime enough to start but not stay running. When installing the new seal the old one fell out of the housing while refueling. At least I now have a spare.

The second was a saw given to me by the boss since it didn't run. On this model there is a separate (3rd) line that ran from the crankcase to the carb which had hardened and fell apart. A chuck of hose from the bench corrected the issue and the saw now runs fine.

I also have a 3rd saw that received a carb rebuild, it came with 2 similar interface gaskets, each had the pulse hole in a different location.

Hope this helps, I hate giving up on a piece of equipment until I'm sure its dead....

[rockrat]

I have seen people use wd40 to help start a balky 2 cycle engine

[smoked turkey]

I have an old red cased Homelight that wouldn't keep running. After quite a bit of time messing with it and no joy, the saw shop put an old used carburetor they had on my saw (couldn't get a new one due to the age of the saw) and now it runs perfectly again. I would try putting the old carburetor back on and see if that is it.

[roysha]

OK. For what it's worth here it goes. A couple of years ago I replaced the upper end on a Stihl. No matt\ter what I did I could not get it running right. This was an aftermarket assembly from who knows where. It acted as though it was incorrectly timed, in regard to the porting. Contacted the vendor. They sent a new assembly and that healed it. If you bought an OEM unit then I doubt this would be your problem but if you bought a "chinese" knockoff, you may never get it running with those parts you have now.

[gwrench]

Check the compression with the new cylinder, it should be around 110-120.

You could still be dealing with an air leak from crank seals. I can't see how straight gas would cause problems with them but it may be age related.