ABarrick
TacomaTRD98 on AS
- Local time
- 7:42 PM
- User ID
- 913
- Joined
- Feb 19, 2016
- Messages
- 523
- Reaction score
- 2,646
- Location
- Newville, PA
Short story: Low hour MS461 with the plastic bearing cage missing in PTO side bearing. Trying to determine the root cause.
Long story:
So a friend of mine brings a 461 (just powerhead, no bar/chain) to me to look at awhile ago and says it was running fine and then he put it away and next time he got it out it wouldn’t start. Felt weird when I tried to pull the rope. Not locked tight, but really dragging. Chain brake was on, so I disengaged it and it pulled normally. I assumed clutch problems so I pulled the clutch cover and tried to take the e-clip off to pull the drum. No go. Could not get it off. It was forced tight to the outer edge of the retaining groove. So I cut the clip with a die grinder and proceed to find what was the needle bearing cage melted and then reformed in behind the washer taking up all the play, hence why the clip would not come out. I put in a new bearing out of my stash and fired it up. It ran ok but something seemed a hair off. I made about 3 cuts and I could feel the chain tightening up. Not getting oil. Pull the drum and clutch and find the worm gear is chewed all to hell and back and the oil pump felt notchy. Also noticed the crank seal was slightly proud from the bearing race. It looked ok otherwise so I knocked it down flush and swap in the oiler parts from my 461 to test run the saw and see how it behaves. Still seemed off. Not horribly poor running but not right. Figured the seal must be leaking so I ordered crank seals and worm gear, etc and set it aside as he said it was no rush. I finally got back to the saw the other day and upon removing the pto crank seal, I find the bearing cage is completely gone. Well, not where it belongs anyway. I found it in crispy piles in the bottom of the muffler cover. Also worth noting, the snap ring that the worm gear rides on lost its hardness. It just folded up when I spread it with snap ring pliers. After I pulled the snap ring, it was easy to see the seal had been hitting it and wore a slight groove in the metal face of the seal. Also noticed the chain coasting at idle so figured the clutch springs are cooked too.
This thing was obviously on nuclear meltdown at some point but my real question is, what started this whole problem? He is adamant the brake was not left on and the drum itself doesn’t have marks from a dragging brake band or anything. He swears it didn’t seem doggy or like the chain was seizing up last time he ran it either. The plastic trim around the drum is not cooked or badly discolored. Muffler was nice sooty black and tune seemed a little rich if anything. Saw is really low hour.
I have new bearings and im hoping the case gasket comes in so I can get this thing done soon, but I figured a few more thoughts on this may help ensure it doesn’t happen again.
I have not split it yet, hopefully time permits this week.
Long story:
So a friend of mine brings a 461 (just powerhead, no bar/chain) to me to look at awhile ago and says it was running fine and then he put it away and next time he got it out it wouldn’t start. Felt weird when I tried to pull the rope. Not locked tight, but really dragging. Chain brake was on, so I disengaged it and it pulled normally. I assumed clutch problems so I pulled the clutch cover and tried to take the e-clip off to pull the drum. No go. Could not get it off. It was forced tight to the outer edge of the retaining groove. So I cut the clip with a die grinder and proceed to find what was the needle bearing cage melted and then reformed in behind the washer taking up all the play, hence why the clip would not come out. I put in a new bearing out of my stash and fired it up. It ran ok but something seemed a hair off. I made about 3 cuts and I could feel the chain tightening up. Not getting oil. Pull the drum and clutch and find the worm gear is chewed all to hell and back and the oil pump felt notchy. Also noticed the crank seal was slightly proud from the bearing race. It looked ok otherwise so I knocked it down flush and swap in the oiler parts from my 461 to test run the saw and see how it behaves. Still seemed off. Not horribly poor running but not right. Figured the seal must be leaking so I ordered crank seals and worm gear, etc and set it aside as he said it was no rush. I finally got back to the saw the other day and upon removing the pto crank seal, I find the bearing cage is completely gone. Well, not where it belongs anyway. I found it in crispy piles in the bottom of the muffler cover. Also worth noting, the snap ring that the worm gear rides on lost its hardness. It just folded up when I spread it with snap ring pliers. After I pulled the snap ring, it was easy to see the seal had been hitting it and wore a slight groove in the metal face of the seal. Also noticed the chain coasting at idle so figured the clutch springs are cooked too.
This thing was obviously on nuclear meltdown at some point but my real question is, what started this whole problem? He is adamant the brake was not left on and the drum itself doesn’t have marks from a dragging brake band or anything. He swears it didn’t seem doggy or like the chain was seizing up last time he ran it either. The plastic trim around the drum is not cooked or badly discolored. Muffler was nice sooty black and tune seemed a little rich if anything. Saw is really low hour.
I have new bearings and im hoping the case gasket comes in so I can get this thing done soon, but I figured a few more thoughts on this may help ensure it doesn’t happen again.
I have not split it yet, hopefully time permits this week.
