Stihl 024 no start

[cbolyard]

Trying to sort out an 024 I have - 155psi compression, rebuilt carb with a Walbro carb kit, no holes that I can find in the intake boot, fuel line or pulse line, no leaks at the crank seals, no leaks at the cylinder base. I replaced the fuel filter when I rebuilt the carb. I could not get it to start with the pull rope but I got the saw to start and run with a shot of ether; however t was idling high and didn't want to adjust down. It ran for maybe 10-15 minutes without missing a hitch. I shut it off and now it won't restart, not a pop or anything. There was fuel in the carb when I opened it up to make sure it was getting fuel. Carb was cleaned in an ultrasonic cleaner prior to rebuilding. I've tried different plugs with no change. I've tried with the air filter on and with it removed, no change.

My thoughts at this point are possibly bad tank vent not allowing air into the tank as the carb is drawing fuel, or maybe the fuel hose is collapsing on itself. Any other suggestions on things to check or try?

 

[SteveSr]

I could not get it to start with the pull rope but I got the saw to start and run with a shot of ether; however t was idling high and didn't want to adjust down.

Classic signs of an air leak. With the age of the saw it is probably the crank seals.

Did you use an OEM carb kit or Chinesium?

Did you adjust the metering lever height when you rebuilt the carb?

 

[cbolyard]

Classic signs of an air leak. With the age of the saw it is probably the crank seals.

Did you use an OEM carb kit or Chinesium?

Did you adjust the metering lever height when you rebuilt the carb?

I will check again for leaking crank seals but did not notice any leaks when I tested it.
Carb kit was OEM.
I don't recall any information in the rebuild kit about adjusting the metering lever height being necessary.

 

[lone wolf]

I will check again for leaking crank seals but did not notice any leaks when I tested it.
Carb kit was OEM.
I don't recall any information in the rebuild kit about adjusting the metering lever height being necessary.

Did you actually pressure test the saw or what?

 

[SteveSr]

Carb kit was OEM.

Who is the OEM?

I don't recall any information in the rebuild kit about adjusting the metering lever height being necessary.

There is never any info with the kits. You have to go to the carb manufacturers web site.

 

[cbolyard]

Who is the OEM?


There is never any info with the kits. You have to go to the carb manufacturers web site.

It's a Walbro carb, I will look and see what info I can find.

Did you actually pressure test the saw or what?

Yes, using a Mityvac through the pulse line. I did not see any signs of bubbles at the crank seals but it's losing pressure somewhere, I'm guessing it's between the mityvac and the pulse line at the moment. I need to mess around with it some more.

 

[wildwes]

Did you replace the fuel and impulse line, or just inspect them? They're cheap, any time I am pulling the carb off of one of those saws I replace the lines, unless I just recently put them on.

If you didn't replace them, have you looked at the end of the line where the fuel filter fits? I had a MS260 recently that started acting like it was starving for fuel, and wouldn't start well- I had just put a new OEM fuel line in it, and within a few days and 2 tanks of gas it had split near the end and was sucking air up instead of fuel.

 

[lone wolf]

It's a Walbro carb, I will look and see what info I can find.

Yes, using a Mityvac through the pulse line. I did not see any signs of bubbles at the crank seals but it's losing pressure somewhere, I'm guessing it's between the mityvac and the pulse line at the moment. I need to mess around with it some more.

Spray a bottle of soapy water on everything until you find it, if not, dip the whole;e thing in water. Also, seals sometimes don't bubble under pressure but leak under vacuum. Do both tests too.

 

[cbolyard]

Did you replace the fuel and impulse line, or just inspect them? They're cheap, any time I am pulling the carb off of one of those saws I replace the lines, unless I just recently put them on.

If you didn't replace them, have you looked at the end of the line where the fuel filter fits? I had a MS260 recently that started acting like it was starving for fuel, and wouldn't start well- I had just put a new OEM fuel line in it, and within a few days and 2 tanks of gas it had split near the end and was sucking air up instead of fuel.

I removed and inspected the fuel line and the pulse line and did find anything to indicate that they were compromised.

Spray a bottle of soapy water on everything until you find it, if not, dip the whole;e thing in water. Also, seals sometimes don't bubble under pressure but leak under vacuum. Do both tests too.

I did put it under both vacuum and pressure, both had slow leaks but I still have not found the source of the leak.

 

[lone wolf]

I removed and inspected the fuel line and the pulse line and did find anything to indicate that they were compromised.


I did put it under both vacuum and pressure, both had slow leaks but I still have not found the source of the leak.

Put a huge gob of greas on the seals and do the test again for both pressure and vac also dunk it completely in water under pressure. L.W.

PS the Spark plug could be leaking too.

 

[wildwes]

PS the Spark plug could be leaking too.

I had a little Homelite that would start, barely, and wouldn't run worth a hill of beans. The spark plug was coming apart and leaking/shorting out.

 

[stihltech]

Find the leak. Then worry about anything else.

 

[lone wolf]

I had a little Homelite that would start, barely, and wouldn't run worth a hill of beans. The spark plug was coming apart and leaking/shorting out.

I had one on an ATV with a hairline crack in the porcelain that you could hardly see, after cleaning out the fuel tank and carb I spotted it.

 

[cbolyard]

PS the Spark plug could be leaking too.

I'll keep tinkering on it as time allows, I appreciate all your input so far.
For what it's worth, I have tried swapping the plug with no success so I don't think a faulty plug is part of the issue in this case.

 

[VincentFR]

I did put it under both vacuum and pressure, both had slow leaks but I still have not found the source of the leak.

Did you rotate the crank during the test? I had a similar issue with a 1989 024. Very small vaccum leak in "static" but big leak when i rotate the crank.

 

[JG33MC]

Trying to sort out an 024 I have - 155psi compression, rebuilt carb with a Walbro carb kit, no holes that I can find in the intake boot, fuel line or pulse line, no leaks at the crank seals, no leaks at the cylinder base. I replaced the fuel filter when I rebuilt the carb. I could not get it to start with the pull rope but I got the saw to start and run with a shot of ether; however t was idling high and didn't want to adjust down. It ran for maybe 10-15 minutes without missing a hitch. I shut it off and now it won't restart, not a pop or anything. There was fuel in the carb when I opened it up to make sure it was getting fuel. Carb was cleaned in an ultrasonic cleaner prior to rebuilding. I've tried different plugs with no change. I've tried with the air filter on and with it removed, no change.

My thoughts at this point are possibly bad tank vent not allowing air into the tank as the carb is drawing fuel, or maybe the fuel hose is collapsing on itself. Any other suggestions on things to check or try?

Hi, I have fixed many saws with this same issue. Without actually viewing the saw in person, it sounds like an air leak in the crankcase, possible due to old brittle and shrunken crankshaft bearing seals or could also be the join between the top and bottom of the case is warped and leaking air. Either of these conditions or both will prevent air/fuel mixture from being drawn from the carb throat as it is sucking air from the leaks instead. An easy test is to simply put some cellophane plastic (Cling wrap) on the carby inlet and put a rubber band around it to seal it tight. Then pull the starter fast several times and get a friend to check to see if it is sucking in the plastic as you are pulling the starter, which it should if the seals are all good. If it doesn't, it means a comnplete strip down to replace seals and reseal the join between bottom and top of the case. Hope that helps

 

[farmhard]

I'd grab the flywheel and clutch and see if there is play in the bearings. You can check a seal for pressure and vacuum and they may seem fine but then the crank moves to one side and bingo. Especially if you are pressure checking unloaded.

 

[cbolyard]

Long overdue update because this saw sat on the back burner for a long time. I started tinkering with it again, replaced the fuel hose and started really scratching the 'ol noodle and finally found the issue. The tank vent was not doing it's job... so the saw now starts and runs. The choke does not seem to be functional so I think a new air filter is in order (this one has the choke flap in the filter). Other than needing a little tuning it seems to be a good runner.

 

[Bob Hedgecutter]

So it still has the original and yet to be discovered/rectified slow air leak on pressure testing though?

 

[cbolyard]

So it still has the original and yet to be discovered/rectified slow air leak on pressure testing though?

The only leak i could find was a very slow leak between the muffler housing and the cylinder which was probably due to the gasket I made to seal off the exhaust for pressure testing. No leaks at the crank seals or cylinder base.