Stihl o41 no start

[mtown]

My o41 is not starting or firing. I have owned since new and it has always started on a couple pulls even when my rope was shortened to allow just a couple inches of pull.
I replaced the rope but then realized the recoil mechanism was also bad. Still started fine but was back to the short pull issue.
I bought a used fuel tank/recoil assembly and installed it a couple months ago. Very simple install and only requires 4 screws and disconnecting the fuel line and re-connecting.

Since the tank was empty of fuel and I had bought a new saw, I just checked the re-coil and set the saw in my basement not wanting fuel to go bad from sitting in tank.

My son wanted to borrow today and could not start after filling tank. I figured the fuel line might be empty so I put mix right in carb and still nothing. The plug when pulled looks fine, the "new" tank lets fuel to line when tipped that way. I am suspecting the toggle "kill switch" but I have removed and checked all wiring to it. No evidence of anything amiss.

Any thoughts?

 

[EngineNoO9]

Impulse line good for carb? Check spark. That will verify your ignition and switch. You verify no cracked fuel lines?

 

[mtown]

Impulse line? Not familiar with that.
The fuel lines all look fine and I am assuming by putting fuel directly in carb and getting no difference rule out fuel.
Thanks

 

[mtown]

I am not sure how to check spark. I did remove plug and with wire on plug pulled the rope. Without the plug grounded I did not expect much though.

 

[EngineNoO9]

Impulse line? Not familiar with that.
The fuel lines all look fine and I am assuming by putting fuel directly in carb and getting no difference rule out fuel.
Thanks

Impulse line runs from the carb to the crankcase. It goes on the carb diaphragm side to work the carb. If you accidently swapped fuel and impulse line that'll definitely make it not work.

Spark plug has to be grounded. Just rest it on the cylinder or use a wire to ground so you can see spark.

 

[CausticUC]

Yeah, always check for spark first, it is easy. Dont even need to pull the plug most times, just pull the plug wire and put any plug into it.

It also sounds like your not getting fuel, if you pulled your plug and it was dry (which is what I take you mean by clean). As you replaced the tank, it is likely your impulse line was missing or broken off.

 

[Tin-knocker]

Yeah, always check for spark first, it is easy. Dont even need to pull the plug most times, just pull the plug wire and put any plug into it.

It also sounds like your not getting fuel, if you pulled your plug and it was dry (which is what I take you mean by clean). As you replaced the tank, it is likely your impulse line was missing or broken off.

I would recommend checking spark with the plug that’s on the saw. If you have a known good plug that throws a spark who’s to say the old plug is still good. The plug could be what’s causing the issue and by using a different plug you might waste time chasing down a problem that was under your nose the whole time. Troubleshooting is a handy tool when used correctly!

 

[mtown]

Thanks, I will clamp the plug to the frame with vice grips and pull to see if I have spark. I am sure it is not fuel. My plug looked "normal" but had some fuel on it from not starting.
I will report my findings.

 

[Wood Doctor]

I hate to throw in a monkey wrench, but my experience has been that 19 times out of 20 the spark plug itself has nothing to do with an engine that will not start unless a guy installs the wrong plug before he gives the saw to me to work on.

 

[Deleted member 117362]

Not a stihl guy, but just finished an 045. Is the impulse line a plug in attached to separation plate between cylinder and carb similar to that 045?

 

[CausticUC]

I would recommend checking spark with the plug that’s on the saw. If you have a known good plug that throws a spark who’s to say the old plug is still good. The plug could be what’s causing the issue and by using a different plug you might waste time chasing down a problem that was under your nose the whole time. Troubleshooting is a handy tool when used correctly!

Fast is first, I'll tell you.

But you are correct, if you get spark in the substitute, then, yes, pull the actual plug for inspection, testing, and the smell test to make sure it's getting fuel.

However if there is no spark, you know to look elsewhere first.

Actually, it seems the older I get the lazier I try to be through efficiency.

 

[CausticUC]

I will just add, on my 041, the split fuel grommet in the top of the tank made starting difficult and would not idle/run properly.

Not sure it would prevent starting completely if it's still pulling a small amount of fuel.

Like selling your soul to buy a new stihl tank fuel line and filter! It is a good thing I rarely need to do it. That and my 031 shares the same ones in a pinch.

 

[Tin-knocker]

I hate to throw in a monkey wrench, but my experience has been that 19 times out of 20 the spark plug itself has nothing to do with an engine that will not start unless a guy installs the wrong plug before he gives the saw to me to work on.

With a 1 in 20 chance of getting a false reading. I’ll take the extra 30 seconds to remove the plug

 

[CausticUC]

The 041 is a bit of a pain to pull the plug it's right at the bottom curve of the handle.

 

[EngineNoO9]

It's a pain but I find an adjustable wrench works easiest on it.

 

[mtown]

That is my exact set up. I had to use a cresent wrench as there was no way to turn a socket.

 

[EngineNoO9]

Take a picture of the carb setup with the cover off.

 

[mtown]

Can't take a picture. Dropped it off to my mechanic this morning. It is the electronic ignition model, not sure what carb. I will post results when I get it back.
I just have a feeling it is a bad kill switch. I could have easily replaced it myself but was told they almost never go bad.

 

[CausticUC]

Can't take a picture. Dropped it off to my mechanic this morning. It is the electronic ignition model, not sure what carb. I will post results when I get it back.
I just have a feeling it is a bad kill switch. I could have easily replaced it myself but was told they almost never go bad.

If it was the kill switch, you can disconnect it and it will run.

Problem is you have to choke it out by covering the muffler or pulling the plug to shut it off. Hard saw to block the intake on even with the air filter off.

 

[EngineNoO9]

I ran my 3700 for a year having to just choke it out. Just didn't want to fix the kill switch wiring.

Why can't you just choke it using the carb choke? That's what I did.