Stihl 045 super idling problem

[tntatro]

Hello, after doing an ignition fix on my 045 super I am now having idling problems. I believe the problem is related to the ignition repair. The repair was done using a Nova II ignition module and I had to advance the timing for it to start and run. This saw did not have the same problem with a different ignition. This same ignition in a different saw made the other saw behave similarly.

It idles but it seems to idle hard. This is a funny way to explain it but as it idles the "blub blub" sound is kind of hard and the chain tends to advance from the "blubbing". I put in new clutch springs and that has not fixed the problem. If I turn the idle down as low as it will go without stalling (around 2,000 - 2,200 rpm) then the chain will not advance much. If I turn the idle up slightly then the chain will start to spin

The saw holds both pressure and vacuum, the compression is around 170 psi, the fuel line holds pressure and I soaked the carburetor in parts cleaner for a few days and then cleaned it and installed a rebuild kit.

The saw seems to run and cut good and has lots of power. I am concerned about running it this way because I don't want to cause damage to the motor. Any ideas on what the problem is or how to fix it would be appreciated.

 

[GPX433Todd]

Low speed too rich?

 

[tntatro]

Low speed too rich?

I don't think it's carburetor related. It's at 1 turn out now and seems to be where it should be. I tried turning it in some to make it more lean but it seemed to be harder to start that way. When I turn it out to make it more rich it kind of had the same problem, it will run if I make it leaner or richer and adjust the idle as necessary but it won't start as easily. I think I've tried three different carburetors, two Tillotsons and a Walbro and they all did the same thing as far as the chain advancing. I also had this ignition in a different chainsaw, an 056 magnum, and the magnum did the same thing when this ignition was in it.

The ignition is a Bosch electronic ignition that failed so I fixed it by using only the coil and a Nova II module. I had to advance the timing to get it to start and run. Others have also done this same fix but I have not heard reports of this problem.

I'm curios if widening the end gap on the piston rings would make it idle more smoothly. The only reason I say that is because one of my 056 magnums has old rings in it and it idles very smoothly compared to this saw and a different 056 magnum I have that both have new Caber rings. Or maybe the rings need to break in more but the other magnum that also idles rough doesn't have a problem with the chain advancing. It's compression is 150 psi, it has an OEM .5 mm cylinder gasket and new Caber rings. The smooth idling one has no cylider gasket, I used Threebond gasket maker, and it has old piston rings that probably have a wide end gap and are probably OEM but I didn't check. Its compression is also 150 psi.

 

[scallywag]

Check your intake boot for holes and any other damage!

 

[AVB]

It idles but it seems to idle hard. This is a funny way to explain it but as it idles the "blub blub" sound is kind of hard and the chain tends to advance from the "blubbing".

Reminds of my old MacCat and Wildcat. When they were new while idling they sit there, well sorta sit there, jumping around while 4 cycling at idle. I first made fun of them but later they turned out to the best home owner saws I ever had. Finally had to retire them after 35+ years because parts were NLA when I needed them.

 

[tntatro]

Check your intake boot for holes and any other damage!

I've re-checked the pressure and vacuum which should cover the intake boot and impulse line. I also replaced the fuel line and it also holds pressure.

When I had a different ignition in this saw it ran normal. The other ignition was the original for this saw but it would fail after the saw was warmed up to operating temperature. That ignition has since been repaired using foggysails method and is now in another saw. This ignition was in that other saw and when it was, that saw had the same problem. I think this problem has something to do with this ignition or maybe the timing. If it idled more smoothly maybe the chain wouldn't advance. Although one of my other 056 saws idles similarly but the chain does not advance. It's a bit confusing to me. I don't care that much about the advancing and I can almost get it to stop. I just don't want to ruin the saw by running it when something is wrong. It does have a lot of power and seems to run good otherwise.

 

[tntatro]

Reminds of my old MacCat and Wildcat. When they were new while idling they sit there, well sorta sit there, jumping around while 4 cycling at idle. I first made fun of them but later they turned out to the best home owner saws I ever had. Finally had to retire them after 35+ years because parts were NLA when I needed them.

Is that what it is called? 4 cycling at idle? I have two 056 magnums and this 045 super. This super and one of the magnums bounces around at idle. The other magnum idles nice and smooth. The one that idles smooth is the most beat up out of the bunch. It is missing a couple cooling fins and the top of the piston was melted on the exhaust side at some point (that way when I got it). I usually put new Caber rings in when I rebuild but that time I decided to use the originals. So now I am curious if the rings help it to idle more smoothly. Just a theory. Both the other saws have new caber rings and the motors were in much better condition with better specs.

 

[deereguy]

I have several 056's (foggy-ed and non). Seems to me, they all bounce around. Nature of the saw design. That saw loves to get into a stack of big wood. deereguy

 

[tntatro]

I have several 056's (foggy-ed and non). Seems to me, they all bounce around. Nature of the saw design. That saw loves to get into a stack of big wood. deereguy

Yes, it doesn't seem like anything abnormal, I'm just confused about the chain advancing. Also, this one seems to "blub" or I guess 4 cycle slightly more heavily. The advancing of the chain seems to coincide with the hard "blubbing" so I thought that if I could figure out how to smooth the idle then maybe the chain would stop advancing. Even at 2,300 rpm it will advance. I think on these saws the chain is supposed to stop moving below 2,500 rpm.

 

[tntatro]

I decided to remove the cylinder and add a cylinder gasket to see if it would idle better. I had used Threebond to make a gasket when it was having trouble starting a while back to see if it would help. The compression was pretty high at 170psi. The piston is in significantly worse condition than it was when I put it together. It originally had some scoring on the intake side and now it has another deep score mark on the intake and wear and light scoring on the exhaust side. I put in a .5 mm cylinder gasket and a lightly used aftermarket Golf piston with Caber rings but have not tried running it yet. Something isn't right about it.

 

[Wood Doctor]

This saw is worth fixing, so don't give up. One of my best friends bought this one from me recently and loves it. He says it will run right with an MS650. I was impressed at its power, even if it weighs more than I care to lug around these days:

Dang thing is built like a tank.

 

[tntatro]

I just printed out a degree wheel so I'll try to figure out how to set the timing this way.

 

[tntatro]

It seems as though I have it figured out. I haven't put it to work yet but it seems to idle pretty good now and starts easily. The throttle response is good and it doesn't flood at idle. The chain still wants to advance but I can get it to idle low enough without stalling to make it stop. I think when it's warmed up it will stop advancing.

A while back when I was first making adjustments for the timing I turned the stator plate all the way clockwise hoping that it would start. It didn't start so I started making adjustments to the flywheel. What I did last night was set the stator plate back to where it should be with the timing marks lined up and then advanced the flywheel 1". I didn't think it mattered where the plate was set if I was changing the flywheel but now it seems to be running normal.

I still have to put it to work and then inspect the piston to make sure nothing bad is happening in there but judging by the way it starts, idles and revs it seems to be good.

 

[JonCraig]

What's going on with the air filter there?

 

[Wood Doctor]

What's going on with the air filter there?

I guess I have to ask the same question. Strange configuration, not stock, makes the filter cover impossible to mount, etc.

 

[tntatro]

I made a velocity stack out of a 2" copper end cap and used foam air filter material for a filter. I also have two saws with Uni Filters but this way was cheaper and seems to work as well. There is also a filter inside the copper piece for extra filtration. This works way better than the original did. I use these 045/056 series saws for milling. The original filters would plug after one cut sometimes. I can use a Uni Filter for days without having to clean it. I use foam filter oil with them also.

The green filters are way better than the black. The saw in this picture had a black one and fine dust got through so I quit using the black one and made the one that is on the 045. I have two green ones similar to the one in this picture and they work great.

Well, I ran the 045 today and it started fine, idled great and I made a small milling cut and it has lots of power. Sat it down and it idled great and then just stopped as if I flicked the switch off. Couldn't get it to start after.

I thought maybe the coil is done for and quits when it gets hot but after messing with it later it would still have spark but not start. I took it apart and checked for loose wires and checked the flywheel and all looked good. Put it back together and it started up again and ran until it got warm, then stalled and wouldn't start but still had spark. This is really confusing me. I'll try a different carb next but if I don't get it figured out soon then it's time for a new ignition. Maybe this coil is just done for.

The blue thing is the capacitor if anyone is wondering. The ignition on this saw has the foggysail fix. Works great so far.

 

[tntatro]

I switched the flywheel and advanced the timing a tiny bit and it stayed running for a while. Didn't put it to work but it didn't die on me. It doesn't idle as well now but better than dying. I guess I'll put it to work tomorrow and see what happens. If it doesn't die on me I may also turn the flywheel back slightly to see if it was actually the flywheel causing problems.

 

[scallywag]

The above saw appears to have a Super or Magnum cylinder fitted?.....Or a 056 av top cover on a Super or Magnum?

 

[tntatro]

The above saw appears to have a Super or Magnum cylinder fitted?.....Or a 056 av top cover on a Super or Magnum?

The case and cylinder are from a magnum and the rest of the parts were swapped from a 52mm 056av.

 

[tntatro]

I just made four milling cuts today and it didn't die on me. It's back to having the chain advance and idle problems. I'll try slightly less advancement on the timing to see what happens.