Stihl MS361 Oil Pump Housing Mess

[MikeDowney]

Replacing clutch and found this mess. Does not appear to be clutch residue, rather, cakes oil sludge. Any ideas how it got this bad? Is this normal after hours of use? What is the best way to clean this mess up.

Also, see worm and spring. The spring was completely loose, not attached to the worm. I assume I just need to replace the worm with a new one?

Any input would be appreciated before I dive into this mess!

Thanks!
Mike

 

[ballisticdoughnut]

Replacing clutch and found this mess. Does not appear to be clutch residue, rather, cakes oil sludge. Any ideas how it got this bad? Is this normal after hours of use? What is the best way to clean this mess up.

Also, see worm and spring. The spring was completely loose, not attached to the worm. I assume I just need to replace the worm with a new one?

Any input would be appreciated before I dive into this mess!

Thanks!
Mike


View attachment 1118026

Need a new worm gear, it will come with a new wire arm. I’d recommend replacing the oil suction hose as well. Get a can of non chlorinated brake parts cleaner and hose it down.

 

[SteveSr]

Replacing clutch and found this mess. Does not appear to be clutch residue, rather, cakes oil sludge. Any ideas how it got this bad? Is this normal after hours of use? What is the best way to clean this mess up.

Also, see worm and spring. The spring was completely loose, not attached to the worm. I assume I just need to replace the worm with a new one?

Any input would be appreciated before I dive into this mess!

Thanks!
Mike


View attachment 1118026

Pour some kerosene/diesel in ther and let it soak for a while. Then go at it with a small flux brush. There may or may not be hole to the outside world under all that gunk somewhere.

Pray that the original owner did not use Bio (vegetable) oil as that stuff will self polymerize and harden like epoxy.

 

[MikeDowney]

Pour some kerosene/diesel in ther and let it soak for a while. Then go at it with a small flux brush. There may or may not be hole to the outside world under all that gunk somewhere.

Pray that the original owner did not use Bio (vegetable) oil as that stuff will self polymerize and harden like epoxy.

Thanks!
I don't have kerosene/diesel available without going to the store....I do have carb cleaner. Would that work?

 

[MikeDowney]

Need a new worm gear, it will come with a new wire arm. I’d recommend replacing the oil suction hose as well. Get a can of non chlorinated brake parts cleaner and hose it down.

Thanks...I'll order a worm gear. On Amazon, only $10 with next day delivery. Will do that.
As for the suction hose, is this it? I have never dug that deep into the oil pump assembly. Is this hard to get to and install? I can't find a YouTube video as to how to replace the hose. Do you think a damaged hose may be the reason for the oily mess?
Again, thanks for sharing.
Mike

 

[SteveSr]

Thanks!
I don't have kerosene/diesel available without going to the store....I do have carb cleaner. Would that work?

You want a cleaner that is going to soak in and not evaporate fast like brake and carb cleaner. Piant thinner/mineral spirits will also work but more expensive.

 

[ballisticdoughnut]

Thanks...I'll order a worm gear. On Amazon, only $10 with next day delivery. Will do that.
As for the suction hose, is this it? I have never dug that deep into the oil pump assembly. Is this hard to get to and install? I can't find a YouTube video as to how to replace the hose. Do you think a damaged hose may be the reason for the oily mess?
Again, thanks for sharing.
Mike

Get OEM parts, should be able to find them on eBay.

1122 647 9400 oil hose
1128 640 7112 worm gear

 

[trains]

Short answer, yes, they get dirty under the clutch like that, also looks like its been overheated as well, the plastics are dark coloured brown, and that would also make the oil/ dust under the clutch bake hard as well.
I hit it with compressed air, then solvent of choice and brush and clean/ air to follow up etc.

the overheat could also could be why the oil drive wire off the nylon gear loose as well.
When you fit the new oil drive gear, put some 2t oil on the bronze bush on the inside of the nylon gear where it runs against the crank.

Might find you need to replace the clutch springs too since its been overheated, they are cheap, get genuine ones.

post pics of it cleaned up.

 

[MikeDowney]

Short answer, yes, they get dirty under the clutch like that, also looks like its been overheated as well, the plastics are dark coloured brown, and that would also make the oil/ dust under the clutch bake hard as well.
I hit it with compressed air, then solvent of choice and brush and clean/ air to follow up etc.

the overheat could also could be why the oil drive wire off the nylon gear loose as well.
When you fit the new oil drive gear, put some 2t oil on the bronze bush on the inside of the nylon gear where it runs against the crank.

Might find you need to replace the clutch springs too since its been overheated, they are cheap, get genuine ones.

post pics of it cleaned up.

Thanks to everyone for guidance. This is the first time I've worked on a chainsaw and couldn't have done it without you all.
I got it cleaned up. I did a bit further cleaning after I took the photo below. Picked out all the small grime with a dental tool and sucked it out with a powerful vacuum.....that worked well.

I really looked hard at the clutch springs and clutch itself. There were no signs of wear.. Springs looked great. I cleaned them up and they look great.

I know you all aren't going to like that I purchased the Worm/Spring off Amazon...but they delivered same day and was only $10. Hopefully I won't regret it. I did not change the oil hose as I was afraid to dig into the chainsaw more than I already did. Upon running, clearly oil was flowing to the chain so hopefully it will last.

Threw in a picture of the before after plastic worm part. New one was obviously needed.

Also a video of it running. The rim sprocket was a bit loose...not a tight fit. You can see it via the video. I assume that's normal as the chainsaw operated just fine...tested it on a big log and was no issue.

Finally, a video with the bar on. Carb might need a bit of an adjustment, but seemed fine to me, but I'm new to this so you may disagree.

 

[MikeDowney]

Thanks to everyone for guidance. This is the first time I've worked on a chainsaw and couldn't have done it without you all.
I got it cleaned up. I did a bit further cleaning after I took the photo below. Picked out all the small grime with a dental tool and sucked it out with a powerful vacuum.....that worked well.

I really looked hard at the clutch springs and clutch itself. There were no signs of wear.. Springs looked great. I cleaned them up and they look great.

I know you all aren't going to like that I purchased the Worm/Spring off Amazon...but they delivered same day and was only $10. Hopefully I won't regret it. I did not change the oil hose as I was afraid to dig into the chainsaw more than I already did. Upon running, clearly oil was flowing to the chain so hopefully it will last.

Threw in a picture of the before after plastic worm part. New one was obviously needed.

Also a video of it running. The rim sprocket was a bit loose...not a tight fit. You can see it via the video. I assume that's normal as the chainsaw operated just fine...tested it on a big log and was no issue.

Finally, a video with the bar on. Carb might need a bit of an adjustment, but seemed fine to me, but I'm new to this so you may disagree.

View attachment Running with Bar.mov

 

[trains]

Thanks to everyone for guidance. This is the first time I've worked on a chainsaw and couldn't have done it without you all.
I got it cleaned up. I did a bit further cleaning after I took the photo below. Picked out all the small grime with a dental tool and sucked it out with a powerful vacuum.....that worked well.

I really looked hard at the clutch springs and clutch itself. There were no signs of wear.. Springs looked great. I cleaned them up and they look great.

I know you all aren't going to like that I purchased the Worm/Spring off Amazon...but they delivered same day and was only $10. Hopefully I won't regret it. I did not change the oil hose as I was afraid to dig into the chainsaw more than I already did. Upon running, clearly oil was flowing to the chain so hopefully it will last.

Threw in a picture of the before after plastic worm part. New one was obviously needed.

Also a video of it running. The rim sprocket was a bit loose...not a tight fit. You can see it via the video. I assume that's normal as the chainsaw operated just fine...tested it on a big log and was no issue.

Finally, a video with the bar on. Carb might need a bit of an adjustment, but seemed fine to me, but I'm new to this so you may disagree.

Well done, reason for mentioning the springs is due to the evidence of the overheat, the springs then loose their temper, and you find with the saw idling, they allow the clutch shoes to move out at a lower rpm and the chain runs before the 3400-3600 rpm that they should engage at.

still downloading the vids, cant see the other one you posted, but could hear it running.
Rim sprocket on the drum will be a bit loose, but again, cant see the videos yet.

Ok, just saw the video, the clutch drum should not be running with it idling like that, I rekon the springs have lost their temper and gone weak.
Bit difficult to be sure, but it sounded a bit lean on the idle side, maybe an 1/8th or less anti clockwise on the L is needed ?

how much grease did you put on the clutch drum bearing, if there is lots, it can drag the clutch drum a bit, but It looked more like idle a bit high, thus suggest making the L richer which will drop the rpm a bit at idle, and the springs too weak.
Clutch drum shouldnt start spinning till 3600ish rpm.

 

[Patrick1903]

@MikeDowney Does it idle ok? And does the chain turn when it is idling (with brake off)?

It appears your top cover/shroud is loose - all fasteners tightened down?

Are you familiar with testing the saw for oil output - i.e. turning nose of bar down towards a piece of cardboard to see if oil is flinging off chain ok? And perhaps you know, but there is an oiler output adjustment on bottom of saw. Crank it up to high to make sure it's lubricating bar/chain.

That saw has taken some abuse; hopefully it has found a more diligent operator in you.

 

[ZeroJunk]

Make sure you got the right worm. Looks like two different heights. And, there are two different height worms at least. Dealer could have gotten them mixed up.
Not sure what it would hurt, but make sure it seats and the bottom isn't rubbing on anything.

The springy thing is not the same length either, and one is round, the other square.

 

[MikeDowney]

@MikeDowney Does it idle ok? And does the chain turn when it is idling (with brake off)?

It appears your top cover/shroud is loose - all fasteners tightened down?

Are you familiar with testing the saw for oil output - i.e. turning nose of bar down towards a piece of cardboard to see if oil is flinging off chain ok? And perhaps you know, but there is an oiler output adjustment on bottom of saw. Crank it up to high to make sure it's lubricating bar/chain.

That saw has taken some abuse; hopefully it has found a more diligent operator in you.

Here's a video of the saw idling (looks like it takes quite a bit of time before the video is available on this site). Chain barely moves. However, after I had done a test cut on a ~15-20" tree, chain moves on idle. Maybe I just need to lower idle a bit? And/or tighten the chain up.

I will have to play around with oil output per your suggestion. I did see a spray of bar oil on my driveway after making the attached video...what an idiot...I was able to clean it off the driveway. I haven't tried the oiler output adjustment. It should be noted that there was only a small amount of clean oil that leaked out after sitting overnight. I assume that's normal.

As for the abuse, I'm assuming you are making that comment based on the mess under the clutch. Yes, that was not a good sign. Based on that, what other areas do you think I should check as a preventative maintenance measure? The air filter and spark plug looked great.

 

[MikeDowney]

Make sure you got the right worm. Looks like two different heights. And, there are two different height worms at least. Dealer could have gotten them mixed up.
Not sure what it would hurt, but make sure it seats and the bottom isn't rubbing on anything.

The springy thing is not the same length either, and one is round, the other square.

The two worms as shown in the picture are certainly different heights. The old one somehow got worn on the top where it is supposed to hold the spring. There is a indentation on the worm to accept the spring. That indentation wore to the point where the spring would not attach to the worm. So good eye...they are different heights due to the worm being worn and no longer accepting the spring. There was no problems that I noticed on seating.

As for the spring not being the same length, I took the attached picture of the old spring held up next to the new installed spring. They look exactly the same to me. Regardless, upon test run, clutch is running great....as far as I can tell.

Thanks for you input

Mike

 

[Patrick1903]

As for the abuse, I'm assuming you are making that comment based on the mess under the clutch. Yes, that was not a good sign. Based on that, what other areas do you think I should check as a preventative maintenance measure? The air filter and spark plug looked great.

No, more so about the heated up plastics and discoloration. Too much heat is bad for crankshaft seals, and can end up causing air leaks into bottom end of saw and allowing engine to run lean - bad! Some times faster idle is result of engine running lean - and could be a sign of an air leak. Not saying that is your issue, but just saying it is possible. I would try turning idle adjustment down to make chain stop turning when idling, after saw it warmed up.

Please watch some of @Vintage Engine Repairs videos on Youtube regarding tuning saw - just to compare your saw, sounds, etc., to how a saw sounds both running rich and lean. Tinman on youtube has a nice demo of tuning carb - and sound of too lean and too rich, etc, under load and off-load.

Regarding oiling - try to remember to clean the groove of your bar every few tanks of fuel. A lot of buildup there can reduce oiling. And yes, oil will come off the saw when it sits overnight, etc. Just search on that on top right - you will get a million discussions about it. If it doesn't leak, it probably because it's empty!

 

[MikeDowney]

No, more so about the heated up plastics and discoloration. Too much heat is bad for crankshaft seals, and can end up causing air leaks into bottom end of saw and allowing engine to run lean - bad! Some times faster idle is result of engine running lean - and could be a sign of an air leak. Not saying that is your issue, but just saying it is possible. I would try turning idle adjustment down to make chain stop turning when idling, after saw it warmed up.

Please watch some of @Vintage Engine Repairs videos on Youtube regarding tuning saw - just to compare your saw, sounds, etc., to how a saw sounds both running rich and lean. Tinman on youtube has a nice demo of tuning carb - and sound of too lean and too rich, etc, under load and off-load.

Regarding oiling - try to remember to clean the groove of your bar every few tanks of fuel. A lot of buildup there can reduce oiling. And yes, oil will come off the saw when it sits overnight, etc. Just search on that on top right - you will get a million discussions about it. If it doesn't leak, it probably because it's empty!

Great suggestions...thanks!

I have a free flow dual port muffler coming in from ebay today. I may do a post on my experience with it. I'm sure you have some thoughts!
https://www.ebay.com/itm/303392063584

 

[ericm979]

If there aren't spark arrestor screens in that new loud muffler, you might not want to use it during fire season. I don't know if your state requires spark arrestors but even if it doesn't, you don't want to be that guy who burnt the neighborhood or forest down (and if you start a fire in a national forest you might get charged for the cost of suppression).

 

[cookies]

Remove the springs, inspect where they hook, they will wear into the clutch, the springs are replaced often as they are wear items and the clutch shoes inspected. Never use carb cleaner on saws where it can get on crank seals, carb gaskets or any rubber hoses, boots or even av buffers as it destroys all types of rubber. Only use stihl oiler worm gears, all the aftermarket ones I have tried do not fit properly in one way or another esp their arms.

 

[MikeDowney]

If there aren't spark arrestor screens in that new loud muffler, you might not want to use it during fire season. I don't know if your state requires spark arrestors but even if it doesn't, you don't want to be that guy who burnt the neighborhood or forest down (and if you start a fire in a national forest you might get charged for the cost of suppression).

Great suggestions...thanks!

I have a free flow dual port muffler coming in from ebay today. I may do a post on my experience with it. I'm sure you have some thoughts!
https://www.ebay.com/itm/303392063584

Got free flow dual port muffler installed. Significant difference in power....a it louder!

Like the clutch repair, was a mess once I got the old muffler off. Before and after cleanup pictures attached