STIHL 041AV starting problems

[GroenJakkalse]

Hi all!

I've just finished restoring my old Stihl 041AV but I have problem with starting.

It was sitting on a shelf for at least 12 years so I had to change all gaskets and rebuild carburetor. I also installed new spark plug.
I didn't need to open crankcase since there was no oil leakage, piston and cylinder are in a good shape.

I put all together and tried to start it. Spark plug gives a spark but it's totally dry. Fuel doesn't come to cylinder so I guess there is a problem with carburetor.

I've read there could be problem with impulse line and/or stuck needle in carburetor.
Impulse line is a bit loose on the carb nipple. Unfortunately shop is closed already so I can not buy another one and change.

Any other ideas what could be wrong?

I'll post some pictures when I come home.

Thanks.

 

[atvhead]

IIRC - the 041s had a least two versions of an impulse line throughout their history. one of which was a now somewhat difficult to find one with molded connections.

041s are also notorious for needed new fuel lines and impulse lines. if you did not replace those yet, do not waste another dime or minute working on the saw. get new ones.

 

[GroenJakkalse]

OK, will try that.

So if there are known issues with these lines do you suggest buying some aftermarket Tygon lines?

 

[TPA]

Standard 1/8" id X 1/4 od tubing works fine for all 041 versions (both fuel and impulse lines).

Before you assume that you have no fuel delivery, test to see that your assumption is correct. Pour a very small amout of fuel mix straight down the carb and try to start. After a few pulls it should fire up and run for about 2 seconds. If it does not start this way, you have a different problem.

For no fuel, check the following since you did a carb rebuild.

-on the side of the carb with the large diaphragm, make sure to put the gasket on first then the diaphragm. Reversing the order causes the needle to stay open all the time (flooding, which you said was not your problem).

-make sure the metering lever (the part that connect to the diaphragm) is level with the sides of the carb. If you installed a new one with the carb kit, it should be correct unless it got bent.

-make sure you have your H and L adjustment presets correct.

-make sure that there are no plugged passages. spray cleaner through and make sure it comes out where it is supposed to.

-suck gas up through the fuel line (with something other than your mouth) to make sure there is no blockage there.

-Make sure that you have your fuel and impulse lines connected to the right places and not switched.

Hope one of these does the trick!

 

[locofrog]

I have an 041 I'm working on as well. It will start if ou prime the carb with fuel through the intake. After it starts it runs fine at idle and revs fine. It won't start on its own though. You have to prime it every time. Hot start or cold start, it doesn't matter. What do y'all make of that?
Also, sorry for the hijack.

Loco

 

[pioneerguy600]

I have an 041 I'm working on as well. It will start if ou prime the carb with fuel through the intake. After it starts it runs fine at idle and revs fine. It won't start on its own though. You have to prime it every time. Hot start or cold start, it doesn't matter. What do y'all make of that?
Also, sorry for the hijack.

Loco

Most likely you have no fuel in the carb, a thorough cleaning and a new kit will fix that. Make sure the fuel line from the tank to the carb is still in good condition along with the tank filter.

 

[GroenJakkalse]

Standard 1/8" id X 1/4 od tubing works fine for all 041 versions (both fuel and impulse lines).

Before you assume that you have no fuel delivery, test to see that your assumption is correct. Pour a very small amout of fuel mix straight down the carb and try to start. After a few pulls it should fire up and run for about 2 seconds. If it does not start this way, you have a different problem.

For no fuel, check the following since you did a carb rebuild.

-on the side of the carb with the large diaphragm, make sure to put the gasket on first then the diaphragm. Reversing the order causes the needle to stay open all the time (flooding, which you said was not your problem).

-make sure the metering lever (the part that connect to the diaphragm) is level with the sides of the carb. If you installed a new one with the carb kit, it should be correct unless it got bent.

-make sure you have your H and L adjustment presets correct.

-make sure that there are no plugged passages. spray cleaner through and make sure it comes out where it is supposed to.

-suck gas up through the fuel line (with something other than your mouth) to make sure there is no blockage there.

-Make sure that you have your fuel and impulse lines connected to the right places and not switched.

Hope one of these does the trick!

Ok, I don't know what could be wrong now. Tried with pouring mixture directly through carb and it doesn't fire up.

I've installed new line, checked the metering lever and diaphragm and everything you suggested. Except H and L adjustments. What is the best setting to start with?

 

[TPA]

The initial settings are:

L - 1 to 1-1/4 turn from full seated position
H - 3/4 to 7/8 turn from full seated

However, pouring gas directly into the carb bypasses the carb altogether and the settings have little meaning unless the carb is dumping more fuel in causing flooding. Do you have fuel residue on the muffler? This would indicate flooding, but you said everything is dry, so this leads me to believe there is a different issue. Here are a couple more things to look at.

1. Test the compression - A saw will not start if compression is below about 100 psi or so.

2. Check for air leaks wherever you can. If you have a pressure tester, keep moving the rubber blockers around to see if each of the intake gaskets are sealing properly. Saw will run lean with some minor leaking, and will not start at all if the leaks get too bad.

3. Look very closely at your sparkplug wire and ignition switch wire. If there are any cracks, you could be arcing at those locations. If that happens you can still see a spark at the plug but it will be too weak to fire the saw. If you see cracks, tape them up and see if the saw cranks, if it does do a permanent replacement of both.

 

[GroenJakkalse]

Yesterday I checked wires and set carburetor. To be sure that fuel is coming to cylinder I removed spark plug, made some pulls and rear handle was soon covered with fuel.
I tried to start but no success.
Although there was some smoke going out from muffler but I guess the compression is too low to start.
There has to be some problems with oil seals. Left it over night with full tank and in the morning there was a lot of oil on the work bench.

I'll take saw to the dealer to check compression and seals. I don't have the right tools to do it.

Thanks for your help.

 

[orangesawRookie]

Got mine running today after sitting for a few years. New impulse line/fuel line, new sprocket, new needle bearing and new clutch.
Is there an "easy" way to replace crank bearings without pulling apart the saw?

 

[stihltech]

041 has points (unless it is an AVE) . Is the spark good? Is the timing set? Passed a vacuum and pressure test?

 

[orangesawRookie]

Yeah it's all good. Bearing just seamed a little bit tough to turn freehand. I shot rem oil at it. Saws running good but don't want to start cutting and the bearing blow up

 

[Backstage]

sometimes bearings are lubricated by the fuel/oil. Could be that yours had some hardened gunk that just needed working loose.