Stihl 038 timing issue

[Tyl206]

Hi,
I am having a problem with starting my saw, it is a Stihl 038 Super. I just did rebuild (cylinder, piston, crank bearings, and seals) I had it running last fall, it was running very well it randomly quit and couldn't get it to restart. I put it away for the winter. Just the other day I got fresh gas and gave it a shot and still no start. I checked the basics: Has spark and is getting fuel. Ive had issues with timing which is most likely the issue, the keyway on the crank had been sheared off, Ive tried marking it and reinstalling flywheel but still no go. I don't think the flywheel is spinning out of time, cause I am making sure I install tight. I am thinking the flywheel is 180 degrees out. What position should the piston be at in correlation to the flywheel/coil mark. I appreciate any help.

 

[Mad Professor]

At TDC the keyway will be about 60o CCW from the rod journal (journal at 0o/TDC), you should be able to see the slot in the flywheel with the nut removed. At TDC the leading edge of the flywheel magnet will be in line with the top edge of your coil and the rest of the magnet lined up with the coil assy,

I'd just get a new keyway, or mark your flywheel/case with the keyway on the crank/flywheel lined up.

 

[Tyl206]

At TDC the keyway will be about 60o CCW from the rod journal (journal at 0o/TDC), you should be able to see the slot in the flywheel with the nut removed. At TDC the leading edge of the flywheel magnet will be in line with the top edge of your coil and the rest of the magnet lined up with the coil assy,

I'd just get a new keyway, or mark your flywheel/case with the keyway on the crank/flywheel lined up.

Alright so I have tried resetting the timing about 5 times still with no start. I marked the flywheel and case and after installing flywheel all marks line up. I started raising suspicion that the coil is getting weak (original coil). I checked the spark I saw it was making spark most of the time but only seems to make good spark when I pull the cord hard to get many rotations. I did get slight shock when I touched the metal case on accident. At this point I am not sure if it is the timing or coil. I rechecked flywheel position marks and all seem to be lined up (to rule out flywheel rotation while starting with no keyway) seems fine. I am 100% sure it is getting fresh fuel and am using spare spark plug to rule that out. If the coil spark seems normal than can you describe how the flywheel magnets should be orientated in comparison to coil? This is how I have been doing it: Placing flywheel on crank so the keyway on crank and flywheel would match up. I make marks on the case and flywheel to hold that position. All done at TDC. There was one time I did place the flywheel in a different position and got a popping sound while starting, which told me the timing was probably wrong. I would replace the keyway but it is sheared off clean and can not remove it. When this saw was running it did have a tendency to stall and be hard restarting or would not hold an idle for more than a minute or two unless I blimp throttle to keep running.

 

[pioneerguy600]

Place a small punch on one end of that sheared off key in the crank, give it a solid whack with a small ballpein hammer,it will rotate up on the opposite end and you can grab it with vise grips and pull it out.

 

[smokey7]

Do you have compression? Pull the muffler and look at the piston. Post some pics. Maybe someone will spit something out of place. Also you should not get shocked anywhere you touch on the saw.

 

[Duane(Pa)]

Disconnect the coil grounding wire from the case or master control lever. I have no idea how the key would shear off. Was there some kind of catastrophe?

 

[Tyl206]

Do you have compression? Pull the muffler and look at the piston. Post some pics. Maybe someone will spit something out of place. Also you should not get shocked anywhere you touch on the saw.

I do not have compression tester but I can tell it is holding compression if I cover spark plug hole. The piston, rings, and cylinder are brand new, maybe 3-4 hours of use max. I definitely got a good zap when I was holding the upper handle..Not sure if that is telling me to replace the coil now? That would be a easy fix. And also I have checked the switch and seems to work fine. The key sheared off is my fault, I should have used hand tools and not cordless impact to remove flywheel nut..I do not use impact anymore. But basically I am getting fuel, probably flooding it as the plug is very wet and had fuel dump out of the intake boot. I am getting some spark, not sure if it is weak or not but I do see it when I pull hard. The timing seems to hold without the key in place, I set piston at TDC and install flywheel by making marks on case and flywheel so assure I am getting the same position if I had the key on. I hold the clutch side of crank so crank does not spin when I install flywheel. I can't even get the saw to start or sound like it wants to start, I don't get it.

 

[smokey7]

Flip the saw upside down with the plug out turn it over a bunch of times to purge the case of piddled fuel. Then leave overnight with Bo fuel in the tank. Try the next day after atleast 12 hours open to start it. Also inspect the high tension lead from the coil to the plug looking for any cracks or bare burnt spots. Wrap with electrical tape temporarily. Then try to start.

 

[Tyl206]

Flip the saw upside down with the plug out turn it over a bunch of times to purge the case of piddled fuel. Then leave overnight with Bo fuel in the tank. Try the next day after atleast 12 hours open to start it. Also inspect the high tension lead from the coil to the plug looking for any cracks or bare burnt spots. Wrap with electrical tape temporarily. Then try to start.

I will leave saw upside down and drain out any extra fuel. I did find a worn spot on spark plug wire where it has rubbed on the upper anti vibration mount. I covered will electrical tape but still didn't start. The terminal to the switch didn't look the best either. Im fairly sure before I wrapped the wire it was arching somewhere along the wire. Is this enough reason to replace coil which comes with new leads?

 

[Tyl206]

I have bought a new coil and new impulse line. The impulse line probably not the issue but looked like needed to be replaced anyways. I will report back once I receive and install parts.

 

[Tyl206]

OK so I have received the coil and impulse line. Installed. It did not want to start at first but I let it sit for a few minutes, turned choke on, and fired up for about 3 seconds and then died out. I got it to do that a few times only with choke on and never running more than 3 seconds. Now I can say at least the timing is ok and spark is ok. But leaves fuel and compression. About 3 years ago I had a very similar issue where it would do same thing. I brought it to a local small engine repair and he said carb was the issue, he rebuilt it and ran really good up until a year ago. After starting the plug is wet. Next compression I think is great (new cylinder , rings and piston) I can hold the saw by pull cord and maybe drops 3-4 inches. Im guessing fuel issue leading to the carb. Opinions??

 

[Tyl206]

Still can not get it to start and run. I took carb off and inspected. The mounting gasket for carb looks rough. Could this be the culprit? I'm betting it is a carb problem..when I adjust the high or low settings, one of them has some resistance more than other side.

 

[Bigjon]

Sounds like you're metering valve stuck open

 

[Mad Professor]

Is the metal sleeve that fits inside the intake boot, in front of the carb there?

 

[Bigjon]

Is the metal sleeve that fits inside the intake boot, in front of the carb there?

Ok, i must ask if that ring has some short of mixing purpose, or is it just stability for the boot. ? Forgot to put mine back in on my 038 super after a rebuild

 

[Mad Professor]

Still can not get it to start and run. I took carb off and inspected. The mounting gasket for carb looks rough. Could this be the culprit? I'm betting it is a carb problem..when I adjust the high or low settings, one of them has some resistance more than other side.

A bad gasket or intake boot/elbow that leaks will give you problems.

Also, did your new coil come with a coil wire or are you using the old one? If the wire is off the coil, check the wire with an ohm meter for continuity and be sure the leg spring that contacts the plug is fitted properly/has continuity.

Bigjon, the saw might run O.K. without the metal sleeve but if the boot does not seal you will have a leak. Note that the boot seals around the elbow/impulse passage that leads to the carb besides sealing the carb intake itself

 

[Tyl206]

A bad gasket or intake boot/elbow that leaks will give you problems.

Also, did your new coil come with a coil wire or are you using the old one? If the wire is off the coil, check the wire with an ohm meter for continuity and be sure the leg spring that contacts the plug is fitted properly/has continuity.

Bigjon, the saw might run O.K. without the metal sleeve but if the boot does not seal you will have a leak. Note that the boot seals around the elbow/impulse passage that leads to the carb besides sealing the carb intake itself

I believe the intake boot is ok, the new coil came with new wires. I will try and take some photos and show how things look. Also the saw seems to be leaking bar oil, I thought it was the o-ring in the oiler but when I took the handle off it looked like the oil was leaking from between the split case. I installed new gasket between the two cases.