# Chain saw oiler



## jackson (May 6, 2008)

Hello All, The chain oiler on my 14" Sears Craftsman chain saw 358.352090 has quit. I drained the oil and flushed it out. The metering hole and filter are clear. I fished a wire all the way through from the metering device to where it exits the case near the chain bar - all clear. I replaced the o-ring on the filler cap - fits tight. I don't know what is supposed to make the oil flow through the tube to the chain. Is it pressure or pump or ? The parts diagram shows a thing called an "oil tank pressure check valve" but I can't find where it's located, maybe in the crankcase?

Any thoughts about how to get the oil to flow again?


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## 30yearTech (Sep 14, 2006)

This oiler system works off of crankcase pressure that flows through a check valve and pressurized the oiler tank. It's probably a bad check valve part no. 530069142 that may need replacement. It screws into the crankcase just behind the chain sprocket. It list's for $6.89 at Sears on line.


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## jackson (May 6, 2008)

Ah HA! I do see a hex bolt, in front of the spocket. I'm a little leary of removing it though. It's just a bolt into the side of the case with no clue as to what it screws into. Is the check valve inside the case or outside?


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## 30yearTech (Sep 14, 2006)

That bolt head you see is the check valve. It's an assembly it just screws in and out, it's not serviceable. Once you remove it you can see pretty much how it works. Pressure is vented from the crankcase and into the oil tank via a little port in the side of the bolt after it flows though a check ball assembly.


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## jackson (May 6, 2008)

OK, I'll pull it out and take a look. But, about the pressure. The pressure comes from engine blow-by I presume and pressurizes the crankcase, which is full of chain lube oil. The pressure pushes the oil from the chain oil tank out through the tube to the chain. If the pressure is not being relieved as it is supposed to because of a bad check valve, where is the pressure going?


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## 30yearTech (Sep 14, 2006)

The check valve just lets a little pressure out of the crankcase and into the oiler tank. The pressure does not have to go anywhere, but if the check valve were to stick in an open position, there would be an air leak into the crankcase that would affect the performance of the engine.

If you look closely at the oiler port you will see a little wire sticking out through a hole, this is a vent that allows the pressure to "bleed" out of the tank. This type of oiler system continues to feed oil after the engine is shut off, until the pressure in the oil tank had dropped. It's a very crude type of oiling system, but it does put oil on the bar and chain (when it's working) lol.


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## jackson (May 6, 2008)

OK, I cleaned the bolt/check valve assembly with spray carb cleaner. I can blow through the screen on the end of the bolt out through the small hole just behing the head of the bolt, which I believe is as it should be. I cannot determine though if the it blows back though; too hard to tell. I did order a new part.

If the ball was indeed stuck open, creating a leak into the crankcase, how would that affect engine performance? It runs like a champ.


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## 30yearTech (Sep 14, 2006)

If the check valve is leaking it will allow the engine to run lean and loose power under a load, they usually will not idle good and may die when throttled and or when the throttle is released.


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## jackson (May 6, 2008)

The new check valve arrived and I installed it. The oil is flowing now just fine, better than ever! For a long time I had been thinning the oil with about 1/3 diesel oil so it would flow better. That may be too thin now. The engine idles a lot better now too! It's running great! Thanks for your help. I owe you a one.


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