MS 660 rebuild advice

[Fnkfab]

It won't pump oil with the drive spring not connected to the clutch drum, unless debris or broken parts are jammed up making the spring/pump turn. If that was the case your chain would be spinning all the time even at idle.

Have a look at the oil line from the pump to the oil outlet in the case. You'll need to pull the clutch off. Need to anyway to replace drive spring.

I'm thinking i see how this works: The clutch drum grabs the spring, spring turns the worm gear, pumps from the bottom hole through the pump to top hole in the case. Both are sealed/grommeted. Goes through case out to bar.

Given my symptom was a mild leak when off/idle-- and absolutely flooding the chain and everywhere from the chain guard at WOT, that means positive pressure leak, so either the upper seal, pump itself, or case itself?Or maybe the pump is just open all the way and ive cleaned the saw out and id never seen a pump at full open? Let's assume that the spring is snapped on the end but has enough interference to be engaged at WOT

So what to do?
Replace spring
Clean upper grommet/gasket thing
Re-assemble
Turn pump down
Do i run the saw with the bar off and see where its dripping from?

Clean out/replace equalization valve?
Any chance it could be the plug on the pump?

Photos below.

 

[BuckthornBonnie]

Yes, 066/660 do not have an oil line to the case.
Leak points are as you discussed. Carefully clean everything and inspect. The little pump-to case grommet can fail. Put everything back together with potentially a new worm gear or spring/tang, torque the clutch and put the drum on, and run the saw to see where exactly the oil is coming from.

Any wiggle to that crankshaft??

 

[Mad Professor]

I shouldn't had used "oil line", that pump seals to case with a sealing ring, the line is the case itself.

The pump has a number of o-rings. Check the plug, worm and pump piston/pump body for wear.

You can upgrade pump to HD version by replacing the control bolt and pump piston.

The vent can also leak, but I'd suspect the pump.

 

[Fnkfab]

The pump has a number of o-rings. Check the plug, worm and pump piston/pump body for wear.

You can upgrade pump to HD version by replacing the control bolt and pump piston.

The vent can also leak, but I'd suspect the pump.

Given the leak opens up at WOT seems unlikely to be the vent valve. I'll dissemble the pump and see what we have. New pumps are pricey!
HD = high flow? or is there heavy duty pump?

Yes, 066/660 do not have an oil line to the case.
Leak points are as you discussed. Carefully clean everything and inspect. The little pump-to case grommet can fail. Put everything back together with potentially a new worm gear or spring/tang, torque the clutch and put the drum on, and run the saw to see where exactly the oil is coming from.

Any wiggle to that crankshaft??

I'm into this. I'll need to sort my stripped crank threads on the recoil side to turn this thing on. Wish me luck there.. just ordered a helicoil set from mcmaster.

WRT to crank shaft, you can slide the crank side to side a bit. It doesn't twist/wiggle. Whatcha thinking?

 

[BuckthornBonnie]

If the main crankshaft can slide/move, it’s not good. It could be a sign of: a spun shaft, bad bearings, or a bad case bearing pocket.

Try to take a video of you moving the shaft and post it here. You may need a vimeo or YouTube account. It will tell us a lot.

 

[Fnkfab]

That saw looks like it has been rode hard and put away wet.

I've never heard this phrase before-- i assume it refers to a wet leather saddle? I love it. It describes this saw well. My plan here was to get it back up and running, learn a bit, and then tear down over winter/spring. Have a lot of projects and have 2-3 trees ready to mill on the property. I also sold out of all my slabs-- seems like people are slab crazy this year.

That said-- its getting a lot less scary as I take more and more things apart-- at this point, i think the only thing i haven't done is separate the fuel tank section and the crank case, and crack the case open. I could be convinced to take it all the way down now-- would probably go much faster now that i know how most of it comes apart/goes together.

 

[Fnkfab]

If the main crankshaft can slide/move, it’s not good. It could be a sign of: a spun shaft, bad bearings, or a bad case bearing pocket.

Try to take a video of you moving the shaft and post it here. You may need a vimeo or YouTube account. It will tell us a lot.

Wait. I think have my terms wrong. The main shaft is tight AF. No play. Bearings feel good-- no gritty feeling and no slop. Given with how the rest of the saw looks, i'd say they've been replaced. The arm that comes up to the piston (don't know what to call this) can slide left/right on the crank shaft assembly but does not twist. No plans to capture this on video unless i opt to pull off the cylinder again--- and seals are back ordered until september so i'm not itching to do that unless you guys tell me there's an obvious thing i gotta get in there and fix.

 

[Mad Professor]

Wait. I think have my terms wrong. The main shaft is tight AF. No play. Bearings feel good-- no gritty feeling and no slop. Given with how the rest of the saw looks, i'd say they've been replaced. The arm that comes up to the piston (don't know what to call this) can slide left/right on the crank shaft assembly but does not twist. No plans to capture this on video unless i opt to pull off the cylinder again--- and seals are back ordered until september so i'm not itching to do that unless you guys tell me there's an obvious thing i gotta get in there and fix.

Side play is normal on lower rod bearing.

Don't buy seals, the complete gasket set has them and priced better

 

[Mad Professor]

HD = high flow? or is there heavy duty pump?

For milling more oil is desired. Only differences in HD pump is piston and control screw.

 

[BuckthornBonnie]

Wait. I think have my terms wrong. The main shaft is tight AF. No play. Bearings feel good-- no gritty feeling and no slop. Given with how the rest of the saw looks, i'd say they've been replaced. The arm that comes up to the piston (don't know what to call this) can slide left/right on the crank shaft assembly but does not twist. No plans to capture this on video unless i opt to pull off the cylinder again--- and seals are back ordered until september so i'm not itching to do that unless you guys tell me there's an obvious thing i gotta get in there and fix.

Gotcha. That arm is the connecting rod and play is normal as mentioned above.

 

[Fnkfab]

For milling more oil is desired. Only differences in HD pump is piston and control screw.

This sounds good to me... any chance you can tell me what part numbers i need or where to look?

 

[Mad Professor]

This sounds good to me... any chance you can tell me what part numbers i need or where to look?

Look in IPL I posted. They are the (Aus) versions.

 

[Fnkfab]

Look in IPL I posted. They are the (Aus) versions.

I dunno what an IPL is but found another thread where you discussed this
Looks like the whole assy is: 1122 640 3201

Parts I'll order:

1. Control bolt o rings: 9646 945 0160
2. Pump piston 1122 647 0602
3. Control bolt 1128 647 4802
4. plug 1125 647 7002
5. gasket 1122 649 5000

Finding these online is tricky. Bailey's pricing for some of these parts would make you think they are made out of gold. (100+ for this list i think)
I can order OEM from https://www.diyspareparts.com/ for $50 shipped from the UK.
I'll see if i can stop by or call the local stihl dealer and have them price it out.

 

[Mad Professor]

I dunno what an IPL is but found another thread where you discussed this
Looks like the whole assy is: 1122 640 3201

Parts I'll order:

1. Control bolt o rings: 9646 945 0160
2. Pump piston 1122 647 0602
3. Control bolt 1128 647 4802
4. plug 1125 647 7002
5. gasket 1122 649 5000

Finding these online is tricky. Bailey's pricing for some of these parts would make you think they are made out of gold. (100+ for this list i think)
I can order OEM from https://www.diyspareparts.com/ for $50 shipped from the UK.
I'll see if i can stop by or call the local stihl dealer and have them price it out.

IPL, = individual parts list

Sorry, was another 066/660 thread I posted these attachments in. Here is IPL and Shop manual.

Those are correct part #s. Any stihl dealer should be able to order the parts, some might do it over the phone if you pay up front. If you wait until they do an order, should be no shipping charge.

2019 prices, control bolt ~$10, piston ~ $35, whole HD pump ~$105. Rest of parts are fairly cheap. Make sure housing is O.K. before you just get HD parts.

P.S. Before you do the work, pull the other cover over the chain break and give the area a good cleaning. If you are not splitting case make sure to protect bearing.

 

[Fnkfab]

IPL, = individual parts list

Here is IPL and Shop manual.

Those are correct part #s. Any stihl dealer should be able to order the parts, some might do it over the phone if you pay up front. If you wait until they do an order, should be no shipping charge.

2019 prices, control bolt ~$10, piston ~ $35, whole HD pump ~$105. Rest of parts are fairly cheap. Make sure housing is O.K. before you just get HD parts.

Thank you! I had not seen the IPL-- been working off service manual and google. This is better!

I took the pump apart-- which was suprisingly easy. I don't own the 2mm drift, but a nail ground down on the end was about right. The housing looks OK to me. WRT leak-- the manual says to pry that plug out-- mine just fell out when i took the oiler off the saw. The o-rings on the control bolt don't look like I imagined them from the diagrams in the manual but they seem on par with images elsewhere on this site.

As an aside-- and to leave bread crumbs for the next poster--- this thread has some nice photos and suggestions some crude methods of modifiying the oiler to get more flow. https://www.arboristsite.com/community/threads/stihl-ms461-oiler.282555/

The website i listed above has some really bad reviews online from recent weeks. I'm going to steer clear. That said-- last time i ordered something from the dealer it took almost 2 weeks to arrive.. wish me luck!

Oh also-- i repaired those case threads for the recoil starter housing with helicoils. I'd never done that--- super easy and pretty cheap. Per the original post about cylinder threads-- a timesert is clearly a million times better, but I'm hoping this is good enough for this application.

 

[Fnkfab]

Oil pump parts on are on order from local dealer--- prob 1+ week to get it here. About 60 USD for bolt, piston and seals.

I also have an AM dual port muffler cover and max flow filter on order. No idea what to expect there-- just pawed through a few threads and that seemed as close enough to a consensus as any.

 

[Mad Professor]

Oil pump parts on are on order from local dealer--- prob 1+ week to get it here. About 60 USD for bolt, piston and seals.

I also have an AM dual port muffler cover and max flow filter on order. No idea what to expect there-- just pawed through a few threads and that seemed as close enough to a consensus as any.

Read up on how to deal with limiter caps on the carburetor. You'll want to retune it after adding the muffler cover and air filter

 

[Fnkfab]

Read up on how to deal with limiter caps on the carburetor. You'll want to retune it after adding the muffler cover and air filter

No limiter caps on my saw.

Any suggested reading material for tuning the saw? The service manual makes it straight forward enough to get started. I've also seen a few youtube videos of people ear tuning. I'm game to try.

Service manual step #2 doesn't quite make sense to me-- how does one reach max engine speed by turning the L screw?

 

[BuckthornBonnie]

When tuning for idle, the L screw will need to be turned in or out until you get the max rpms with the LA setting you have. The videos you mentioned probably describe this procedure.

 

[BuckthornBonnie]

A few posters have videos on YouTube showing tach tuning as well. MasterMech, mweba1, and Brad Snelling, I think. It’s been a while since I’ve watched ‘em, though.
Edit- MasterMech= Brian Lawyer channel. He has captions describing what he is doing. It’ll get ya close... just adjust to the 660 recs but still use your ears.