A hot day, 100:1 mix ratio, a lean tune all combined with small saws cutting 60" wood is what I'd call a recipe for disaster. I hope you can rebuild the cylinders and get your oil ratio sorted out.
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Canyon Angler
Addicted to ArboristSite
I'm not sure the 93 octane is doing you any good, either. Now that MTBE is banned, what they use to boost octane nowadays is ethanol (alcohol) – and 93 octane is going to contain a lot of it.
I use 89 octane non-ethanol gas.
I use 89 octane non-ethanol gas.
Huskybill
Addicted to ArboristSite
My Husqvarna dealer told me to use high test gas in all my power equipment. The Husqvarna saws are high compression engines. I been using the husky mixed 50:1 gas in a can. The saws run awesome just like they did in the pre ethanol days.
Canyon Angler
Addicted to ArboristSite
I don't have many saws, but the ones I have said to run at least 89...mid-grade. Then again, I run Stihl saws, maybe they don't need the super duper uber octane those Husqvarna muscle saws do.
Whatever the case, it's the alcohol that would concern me more than the octane...
Is this the gas thread?
Whatever the case, it's the alcohol that would concern me more than the octane...
Is this the gas thread?
TomKub
ArboristSite Lurker
To clarify, I used a 5.2 oz orange stihl oil mix. On the container it states to use 2 gal of 89 octane. I poured 2 gal of 93 octane emptied two oil mixes and topped off fuel can with 2 gal. Mix ratio is 50:1
Ah ok gotcha, two 5.2 oz bottles, thanks for the clarification. The mix ratio should be good enough then. However I still feel that the gas itself was probably the biggest culprit. If the gas was of poor quality & it had ethanol to boot then that’s no bueno. Of course like folks here have stated the combination of a hot day, high work load and older saws, etc. could definitely have contributed. Both saws could have each had a pre-existing issue and finally gave in. But again, the fact that they both seized in the same day makes me think it was the gas. Either way that was a really unfortunate day! If you don’t feel like fixing that 045 you could always sell it to me! [emoji16]
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drf255
BAD CAD
What happened is unfortunate.
Many people here can help guide you through a rebuild, and 036 cylinders are plentiful.
As mentioned above, cutting on a hot day will make a saw heat up more/faster. That will contribute to a lean tune. If your saws were tuned in the fall and then you cut a 60” tree in 80* heat, your tune likely got leaner than you thought.
Another can of oil in your container is cheap insurance. I mix at 32:1 (24:1 for milling) and use good oil. Never a fouled plug or any other issues at that ratio, just a wet oiled piston.
50:1 is a EPA thing that the OEM’s need to follow. Back “in the day” many manufacturers suggested 16:1-but the oil and equipment were different. Point is that 50:1 really isn’t great for your Equipment. Heck, they gotta sell new saws.
Many people here can help guide you through a rebuild, and 036 cylinders are plentiful.
As mentioned above, cutting on a hot day will make a saw heat up more/faster. That will contribute to a lean tune. If your saws were tuned in the fall and then you cut a 60” tree in 80* heat, your tune likely got leaner than you thought.
Another can of oil in your container is cheap insurance. I mix at 32:1 (24:1 for milling) and use good oil. Never a fouled plug or any other issues at that ratio, just a wet oiled piston.
50:1 is a EPA thing that the OEM’s need to follow. Back “in the day” many manufacturers suggested 16:1-but the oil and equipment were different. Point is that 50:1 really isn’t great for your Equipment. Heck, they gotta sell new saws.
A 40:1 mix ratio and a tad rich tune when horsing saws in hot weather has allowed my saws to live really healthy long lives. A 60" tree is a heavy load on any saw with really long run times in the cut, heat would have built up really high in the cylinder and crankcase and small saws are working harder than 90cc and up torque monsters would be.
Chainsaw Jim
CJ Saws, LLC
That's awfully big wood for such small saws. That's pretty much the same application as milling.
I agree that he was running too lean for that hard of cutting but when you tune in the winter/fall your saw would be running a tad rich in the summertime. Cold air is more dense so you put more oil in to compensate whereas hot air is thinner and if you don't correct your tune you would be running a bit rich. But hot weather will heat up a saw faster than cold weather (obviously). Hot weather or high altitude will require a leaner tune then cold weather/low altitude. Please someone correct me if I'm wrong! Just a stupid sheet metal worker over here
But I think we can all agree that too much heat will kill an engine and hard running in hot weather with a 50:1 mix is what killed those saws
Assumptions is what really killed these saws..
I've been ripping huge rounds in 100 degree heat on 50:1 with no problem. Given the confusion over mix ratios I think the likeliest cause was accidentally using much less than 50:1. I use a Ratio-Rite to avoid having to do math.
Lee@themancave
ArboristSite Lurker
Hutzl offers a replacement p/c kit for the 036. Sell the other one on ebay as is.
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drf255
BAD CAD
You would be correct, my error. That’s in theory.I agree that he was running too lean for that hard of cutting but when you tune in the winter/fall your saw would be running a tad rich in the summertime. Cold air is more dense so you put more oil in to compensate whereas hot air is thinner and if you don't correct your tune you would be running a bit rich. But hot weather will heat up a saw faster than cold weather (obviously). Hot weather or high altitude will require a leaner tune then cold weather/low altitude. Please someone correct me if I'm wrong! Just a stupid sheet metal worker over here
But I think we can all agree that too much heat will kill an engine and hard running in hot weather with a 50:1 mix is what killed those saws
In reality, when I’ve run saws in 100* weather, they heat up more and require a richer mix to keep the rpms down. They don’t get richer as they heat their charge up. Most ported saws I run will gain 1000 rpm pissrevving at there tune after a long cut.
Guess the increased cooling of the engine vs. the thinner air cancel each other out.
Now I’m confused.
TomKub
ArboristSite Lurker
Here is my update. I replaced the piston, cylinder,rings,needle cage and the 036 started right up. After five minutes of cutting I switched saws. Later that day I went to start the 036 and it would not start, didn’t even try to. I took off the exhaust and there was some very faint vertical lines on the piston. Almost identical to the previous piston but much much less in depth. What is going on. On a side note, I mixed a new gas batch 40:1 (1.5 gal of fuel with 5.2 oz of stihl oil.
Hey there Tom, sorry to hear you’re still having trouble. My first suspicion would be your carb is tuned way too lean. However some additional info would be helpful.
-Do you tune the carbs yourself?
-Did you get gas from the same place and did it have more than 10% ethanol?
-Did you inspect the fuel system and do a vacuum leak test on the saw prior to installing the new cylinder?
-Did you install aftermarket or oem Stihl parts.
-Ryan
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How is the saw tuned? Did you vac test it?
TomKub
ArboristSite Lurker
-I tuned them myself. I went an additional 8th turn on the L screw.
-gas was from a different station. Here in Pa 95% of out gas stations have up to 10% ethanol. Closest ethanol free is 30 min away.
-I did not do a vacuum test. I will do that tonight. I’m guessing a vacuum test would show a possible bad crank seal??
- I did not use OEM. $275 vs $45.
How far is your high rpm screw backed out? A bad seal is one culprit that can be causing a vacuum leak. However, before you do a vac test take a look at your intake boot and make sure there are no cracks or holes. Additionally make sure that boot clamp is tight. Also take a look at your impulse line. If those check out and you get a vacuum leak then yes you probably have some worn out oil seals. That or some loose crankcase screws. It would also be a good idea to inspect your fuel line for any holes or cracks.
-Ryan
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-Ryan
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TomKub
ArboristSite Lurker
The 045 runs good after the fresh top end. It’s the 034 that’s acting up now. I’m contemplating a newer saw so the 045 may have to go.
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