I just finished rebuilding a 041 with a new episan piston and rings, new fuel/vacuum lines, crank seals, and o-rings. pressure and vac tested the crankcase. I cleaned the carb again before putting it back on. It was flooding out before I did all this and it is continuing to do that now. It will run if I disconnect the fuel line to the carb and spray fuel mix down the carb throat. Seeing as I have cleaned the carb twice now and put in a new rebuild kit, I'm wondering if something is still plugged (I did remove the welch plugs and cleaned underneath before replacing), or if the carb is just worn out. Anyway to test the carb? I'm considering trying one of the cheap aftermarket carbs. Anyone have any experience with those cheap carbs?
Stihl 041 AV aftermarket carb?
- Thread starter sven556
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Think of it this way, flooding is caused by the needle valve not shutting off the supply of fuel when needed. That means the needle is not sealing to the seat in the carb, something is keeping the needle from sealing off the incoming fuel. You can check to make sure the needle seat is clean and not damaged, a improper install of the metering gasket and diaphragm will also hold the needle off the seat as will a too high setting of the metering lever. Those are the most common reasons a carb floods, the same happens when the metering diaphragm is old and stiff it will hold the needle off the seat. To test the carb for the needle sealing or not you can just connect a vac pump to the fuel inlet nipple and pull a few pounds of vac, if it holds the needle is sealing, if it does not hold vac then the needle is not holding. Many old school mechanics did that test with a short section of fuel line and pulled vac with their mouth, sealing the end of the hose with the tongue, if the vac held the tongue stayed stuck to the end of the line.
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Old school mechanics can do some amazing things with their tongues......
So I have heard......................................
So I have heard......................................
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Softcore tech manual.......
Last night I checked the carb again and made sure needle held a vacuum and the metering lever was set correctly, which it was. I put it back together without doing or changing anything. Put it back on the saw and it fired up. Ran it for a few minutes and shut it down. Tried again about 40 minutes later and it fired back up! Waited awhile again, put a new air filter on (I did not have an air filter on previously) and it wouldn't start... I'll try again tonight, but I think it flooded again. Looks like I'm getting closer to having a running saw. If I can get it running again tonight, I'll put a bar and chain on and try to adjust the carb. I'm not sure what was going on with the carb, maybe the gaskets sealed better when I put it back together this time.
Rockjock
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Are you using a USC cleaner? On really stubborn carbs we had a tech that would soak them in fuel, then let the USC have at it.
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Univ. of South Carolina?
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Have you tested to see if the needle is holding?
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Have you tried buffing the needle seat with a q-tip and something slightly abraisive to polish it?
I did test the needle by pulling a vacuum on the fuel line, it holds. Is the 041 easy to flood if it doesn't fire with the first few pulls? I'm hoping it gets better after I get the carb adjusted and it's getting the proper amount of fuel.
I have found that the 041's are one of the fastest starting saws that I have ever started. Sometimes only half a pull and I can throw the choke off and it is going on a half pull start. I think the long stroke is the factor in quick starting. You MAY be flooding it then again could be something else. Trial and error.
Dave
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You need to do a pressure test.
What about the ignition? Points?
What about the ignition? Points?
The ignition is electronic, SEM. I opened up the gap on an old spark plug as far as I could and it sparked across that. Is there an easy way to test timing? It seemed to run fine once I got it running.
I only had a few minutes to look at the 041 last night but it was enough to make me feel dumb! I removed the air filter plate and found why it wouldn't run after I put the air filter back on, I had pinched the fuel line between the plate and the top of the carb... I'm guessing it will run when I get it back together correctly!
In case someone else is looking at those aftermarket 041 carbs in the future, I bought & used one once. I found the build quality was cheap as you'd expect, but the saw ran better with an OEM kit in the cheapy carb. Also, the adjustments were way off from the factory Tillotson. IIRC, it was 4-stroking big time at WOT w/ the hi at 3/4 of a turn.
I have another 041 with OEM carb, and I spent some time swapping them back and forth making sure I wasn't fooling myself. Just felt wrong having a saw with hi at less than 3/4--was afraid I was going to blow it up!
I have another 041 with OEM carb, and I spent some time swapping them back and forth making sure I wasn't fooling myself. Just felt wrong having a saw with hi at less than 3/4--was afraid I was going to blow it up!
trappermike
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Carbs usually never wear out except if the throttle shaft becomes loose in the body,a proper rebuild should fix it. Yes it sounds like it's flooding. The standard factory test for the inlet needle and seat is a pressure test,Walbro makes a handy little tool for that. I think a vacuum test will merely suck the inlet needle harder intio it's seat and make it appear ok,thats why the manufacturers used a pressure test. However if you have a new needle and the lever is set to correct heieght it should be ok. How about those welch plugs you changed,if they are not re-installed well they can leak fuel too,I use a large flat ended punch slightly less in diameter than the welch plug and carefully drive the new plug in, being sure to expand it enough to seal. Some mechanics the apply some fingernail polish around the edges of the plug to seal the plug.
After sitting does the spark plug get soaked in fuel after the first pull? Maybe remove the spark plug and see if it gushes fuel out after sitting when you first pull the rope.- On a flooded motor keep the spark plug and wire far away from the spark plug hole,many times I've seen fuel gush out and the spark plug ignites creating a flame thrower,one mechanic severely burnt his face!
After sitting does the spark plug get soaked in fuel after the first pull? Maybe remove the spark plug and see if it gushes fuel out after sitting when you first pull the rope.- On a flooded motor keep the spark plug and wire far away from the spark plug hole,many times I've seen fuel gush out and the spark plug ignites creating a flame thrower,one mechanic severely burnt his face!
