Went to the shop this morning and began performing some forensics on the MS250.
1. I began by emptying the oil tank and pulling the oil pick up tube filter. It was clean as could be. No debris in the tank or the filter. The pick up hose looks good and flexible. No problem there.
2. Removed chain adjuster & chain assembly & inspected oil holes in the bar. Clear, but little sign of oil. Again, no problem.
3. Inspected the tank vent valve that is located directly behind the bar and it had a lot of crud built up in the recess. I cleaned it out with some brake cleaner and then with compressed air at a low pressure. That could be the problem.
4. Removed the clutch drum to make sure the worm drive was in place and functioning. It was and I saw no problem there.
5. Since further inspection would require more dis assembly and since I found all of the debris in the oil tank vent, I decided to take it out and run it with out the chain & bar. Started it and immediately began seeing bar oil appear from the oil port. Maybe I cured the problem!
6. I performed a thorough chain inspection and used my grinder to bring it back to life. Filed the bar rails and reassembled the saw, filled it with Stihl Blue Jug Winter Bar Oil and fuel mix.
7. Went outside and fired it up and ran it with varying RPM's for a few minutes and had a nice flood of oil as typical when running a saw free like this. I did notice that it was NOT slinging oil like my other saws do when help close to a log. Most saws will leave a nice oil stripe when revved as we all do to check for oil.
8. Loosened the chain and inspected the teeth and bar and they appeared to be bathed in a nice oil film. Not soaked, but sufficient.
9. Went in & put on my chaps, safety glasses, hard hat with ear protection and headed out to my back 40 where I have a 50' hickory blow down that was waiting to limb & buck. The saw was throwing nice chips of wood and sliced through the ol' Shagbark with ease. I cut up the vast majority of the tree with the little 250 without a problem. No bar smoke and the chain kept its edge as it normally does.
10. I allowed it to run out of fuel so I could accurately measure the amount of bar oil remaining.
11. Went back up to the shop and with zero fuel in the tank, and I poured out the remaining bar oil into a measuring cup. I had right at 2 oz. left in the oil tank. The oil tank capacity is 6.8 oz. With a little simple math, 2 / 6.8 = 29.4% of the oil remained. So in that one tank of fuel the saw dispensed 70.6% of the bar oil.
What did I learn from this? Well, just a few:
- You guys are a good resource of info!
- The little things can cause big problems.
- This saw uses slightly less than 3/4 of a tank of oil when a full tank of fuel is burned.
- A good reminder to clean out all vents often!
How about others who operate an MS250? What kind of bar oil usage do you typically see?
I will continue to watch to see if this crops up again. I will keep you posted. Have a great weekend!