Stihl MS361 Oil Pump Housing Mess

[Stihlhead517]

Looks uy

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

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

K

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

I would try a leak test just to be sure the crank seal is not leaking. A leaky oil seal over time will attract dirt and grime.

 

[ballisticdoughnut]

Make sure you adjust the high speed mixture after installing the modified muffler.

 

[Mad Professor]

The saw needed a bath. I'd clean out flywheel side also.

 

[MikeDowney]

The saw needed a bath. I'd clean out flywheel side also.

Good point. I’ll do that tomorrow.

 

[HansFranz]

Just as another data point FYI...the oiler on my MS361 has been a sh¡t show since Day One. It has never oiled worth a dam. (I can burn probably 5+ tanks of fuel before I use up one tank of oil.) I had the dealer replace the oiler (twice!) under warranty and it still doesn't oil worth a dam. (Now I thin the bar oil with kerosene or cheap hydraulic oil to get it to flow better.) I've heard you can replace the oiler with a high-volume oiler from a 460 (or maybe a 440, I forget) which will address the issue...YMMV since I have not heard of many other people with this problem.

 

[MikeDowney]

Just as another data point FYI...the oiler on my MS361 has been a sh¡t show since Day One. It has never oiled worth a dam. (I can burn probably 5+ tanks of fuel before I use up one tank of oil.) I had the dealer replace the oiler (twice!) under warranty and it still doesn't oil worth a dam. (Now I thin the bar oil with kerosene or cheap hydraulic oil to get it to flow better.) I've heard you can replace the oiler with a high-volume oiler from a 460 (or maybe a 440, I forget) which will address the issue...YMMV since I have not heard of many other people with this problem.

Thanks for the heads-up. Fortunately, my saw is oiling really well.

 

[MikeDowney]

Make sure you adjust the high speed mixture after installing the modified muffler.

I have an RPM meter coming in today. I'll adjust the carb. The RPM's seem significantly higher at full throttle....made me nervous so I only went full throttle once and for a second. Shooting for no more than 12,000 RPM at full throttle...I think I researched that correctly....

 

[MikeDowney]

Looks uy



K

I would try a leak test just to be sure the crank seal is not leaking. A leaky oil seal over time will attract dirt and grime.

How would I go about doing a leak check? Simply removing the clutch after several hour of use and looking for excessive oil?

 

[bwalker]

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.

Brake cleaner will work just fine for this job... spray the hell out of it and then blow out with compressed air.

 

[bwalker]

I have an RPM meter coming in today. I'll adjust the carb. The RPM's seem significantly higher at full throttle....made me nervous so I only went full throttle once and for a second. Shooting for no more than 12,000 RPM at full throttle...I think I researched that correctly....

13500 is the factory spec IIRC. No need to make it pig rich.

 

[bwalker]

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

Looks to me that it was ran with drain oil in the bar oil tank. This area tends to get grungy on all saws.

 

[bwalker]

How would I go about doing a leak check? Simply removing the clutch after several hour of use and looking for excessive oil?

Your saw just has some hours on it. It looks completely normal for a high hour saw.

 

[DND 9000]

13500 is the factory spec IIRC. No need to make it pig rich.

No 14000 is the specification on the MS 361.

 

[Stihlhead517]

How would I go about doing a leak check? Simply removing the clutch after several hour of use and looking for excessive oil?

Leak test is a little involved. You have to block off the exhaust port and the intake port with a piece of flat rubber, put it between the muffler and exhaust port and tighten the bolts back up and do the same with the carburetor and intake port. I use the flat tire patches from harbor freight. You will need a pressure/vacuum pump, I use a Mityvac pump. On the ms361 I would hook it up through the impulse line. Pump in 7psi of pressure and start looking for leaks, don't put too much pressure or you can blow out the crankshaft seals. I use a little soapy water in a spray bottle to look for leaks. Go to YouTube and look for videos on chainsaw leak test. You will find a lot of good stuff. Here is a picture of a leaking flywheel side seal on a Stihl 023.

 

[MikeDowney]

The saw needed a bath. I'd clean out flywheel side also.

You were right!

 

[stihltech]

I would replace the oil supply line in the tank also. Loses its seal from age and overheat. Clean the pickup screen, oil tank and inlet to the pump. Assemble back to enable starting. You can leave the clutch and worm off. Spray brake cleaner around seals, any rubber parts and gaskets. Changes in idle will show up immediately with a leak. The straw on the nozzle will pinpoint the leak.

 

[MikeDowney]

I would replace the oil supply line in the tank also. Loses its seal from age and overheat. Clean the pickup screen, oil tank and inlet to the pump. Assemble back to enable starting. You can leave the clutch and worm off. Spray brake cleaner around seals, any rubber parts and gaskets. Changes in idle will show up immediately with a leak. The straw on the nozzle will pinpoint the leak.

Thanks! I did not do anything but replace the worn Worm that would not hold the spring. New one came with the spring. I cleaned everything up and simply installed. It is running great now....holds idle fine. The chain is oiling well and no excessive chain oil after running and sitting overnight. I'd rather not pull it apart again unless necessary/advisable. Not sure I know what you are referring to "...straw on nozzle"?
Again, thanks for the input which is super valuable to me as I'm just learning.

 

[Chevboy0167]

 

[MikeDowney]

View attachment 1118687

Picture did not fully come through. I assume this is your recommended cleaning solution? Only the top of the can shows.
Thanks!

 

[Chevboy0167]

That is "the straw on nozzle".