McCulloch Chain Saws

[brandonstc6]

I made an adapter that threads into the spark plug hole, knock the porcelain out and thread or epoxy a barb fitting in place. If the saw has a compression release I find it best to remove it and install a plug, 3/8-24 for most American saws and 10 mm for imports and later U.S. made stuff.

View attachment 551566

As long as you have the intake and exhaust ports sealed off it makes no difference where the piston is, the rings don't make a perfect seal in any case.

Mark

I will do that, thanks!


Sent from my iPhone using Tapatalk

 

[Brian Thacker]

I have torn seals while installing them and not know it. A small tare can leak a lot. The sharp edge on the crank where it transitions from the clutch or flywheel seat to where the seal sets is a lip and it can cut the seal if you are not careful. I usually grease the seal and the surface that it has to slide over to help it over the lip on the crank. I also have used a plastic bag put over the shaft to slide the seal on to help it transition over the lip or take a small round pick and help the seal over that lip. Either way be careful and gentle when installing the seal over that lip. Take it easy and don't get in a hurry. If you notice the plates that Mark is using to block off the intake and exhaust he built. They are not hard to build. I used to think I did not have to pressure or vacuum test two strokes because I put all new parts in and thought I sealed everything up good but I have been proven wrong a few times so I always test them. I just rebuilt my son's Suzuki LT-80. I tested it. I just rebuilt a 1974 Bultaco 250 Alpina and you bet I tested it. It just ensures that it is right.

 

[Brian Thacker]

Mark, I just saw your sparkplug/barb setup. I like that. I have one of my blockoff plates that I welded a barb onto and just install a sparkplug in to seal. I think I might steal your design, I like it better.

 

[Brian Thacker]

I usually pressure test first so if I have a leak I can use a soap solution in a spray bottle to help find the leak. They can pass the vacuum test and fail the pressure test. Have seen seals that would hold a vacuum but blow out on pressure for some reason. So I do both.

 

[heimannm]

I install the PTO seal part way on the crankshaft with everything disassembled to make it easier to get it worked over the step in the crankshaft. If you put everything together then try to install the seal, it can be very difficult getting it over the step since the lip is making an even contact all the way around. Think of it as though you were working a tire onto a rim, much easier to start on one side and work your way around.

Mark

 

[PogoInTheWoods]

"I usually pressure test first so if I have a leak I can use a soap solution in a spray bottle to help find the leak. They can pass the vacuum test and fail the pressure test. Have seen seals that would hold a vacuum but blow out on pressure for some reason. So I do both."


Yep. Think of a leaking oil seal as a valve...sometimes just a one way valve. Can hold vac and leak pressure and the other way around. That's why I always test both as well. I use a few methods when testing depending on the saw and any number of variables. (-- spark plug test fitting, intake block w/test fitting, impulse hose direct...). I will typically test a case or shortblock by itself after rebuilding before going any further. I never take anything for granted just because I just installed new parts. Experience taught me that.

The MityVac MV-8500 Silverline is the way to go if you're going to buy a tester. Tests both vacuum and pressure with the flip of a switch/lever.

https://www.google.com/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-8#q=mityvac mv8500

A solid metal unit with all parts replaceable. Well worth the money the first time it finds a leak that could have otherwise toasted a brand new rebuild, not to mention the time it saves chasing your tail and throwing parts at a project when the problem is a simple leak. A home grown setup will do the job just as well, but you can't beat the convenience of a MityVac.

And Mark is correct (thank you, Mark) in the myth busting of where the piston should be when performing a vac/pressure test. Doesn't matter and it can be proven by simply rotating the flywheel while vac or pressure are being applied...which is good practice anyway to make sure the seals stay tight during a couple of revolutions.

 

[PogoInTheWoods]

I think I'll be ok on that bearing, Mark. I'm a big Dirko fan and will apply a thin layer everywhere which should do the trick. Was just a little concerned about the surface grooves on the case halves and the minor anomolies on the bearing. The green Loctite wouldn't be a good choice for this particular application, but works very well between surfaces already assembled -- as in a split case design where the bearing fit in the seat may be a bit questionable.

 

[sawfun]

I had a 125 that I replaced the seals on and found that turning the crank, while installing the outer flywheel side, helped the lip go down much easier.

 

[fechtichmac]

"I usually pressure test first so if I have a leak I can use a soap solution in a spray bottle to help find the leak. They can pass the vacuum test and fail the pressure test. Have seen seals that would hold a vacuum but blow out on pressure for some reason. So I do both."


Yep. Think of a leaking oil seal as a valve...sometimes just a one way valve. Can hold vac and leak pressure and the other way around. That's why I always test both as well. I use a few methods when testing depending on the saw and any number of variables. (-- spark plug test fitting, intake block w/test fitting, impulse hose direct...). I will typically test a case or shortblock by itself after rebuilding before going any further. I never take anything for granted just because I just installed new parts. Experience taught me that.

The MityVac MV-8500 Silverline is the way to go if you're going to buy a tester. Tests both vacuum and pressure with the flip of a switch/lever.

https://www.google.com/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-8#q=mityvac mv8500

A solid metal unit with all parts replaceable. Well worth the money the first time it finds a leak that could have otherwise toasted a brand new rebuild, not to mention the time it saves chasing your tail and throwing parts at a project when the problem is a simple leak. A home grown setup will do the job just as well, but you can't beat the convenience of a MityVac.

And Mark is correct (thank you, Mark) in the myth busting of where the piston should be when performing a vac/pressure test. Doesn't matter and it can be proven by simply rotating the flywheel while vac or pressure are being applied...which is good practice anyway to make sure the seals stay tight during a couple of revolutions.

Have this one - works great
Pressure and vacuum - I also do always both.
E.

Gesendet von meinem SM-G928F mit Tapatalk

 

[fossil]

Tim - Did you take into account that 61618 is the McCulloch part number and not an SKF or CR part number? I started to keep track of seals and bearings once but my notes seem to have drifted off before I ever got far on compiling the data.

Mark

Yes I did Mark. Eccentric and a few others (me too) are putting together a list of seals and bearings which cross to aftermarket. The list is getting longer and it's been ongoing for a couple of years. I can't attest to all the crosses but I know most are good. There is some reluctance to share the list at this time as some of the info could be inaccurate.

Anytime I cross reference a seal and use it I would update the list and send it back to Aaron. He is the keeper and organizer of the list.

The list is by OEM PN and then the alternate seal or bearing.

 

[PogoInTheWoods]

Neglected to include this in my earlier post.

One more vac/pressure test I do after ensuring the case integrity is the intake assembly once things are going back together. Depending on the saw, that could mean reed block, intake boot, intake gaskets, impulse line/passage, bulkheads, all of the above, etc. I also make sure to test the decomp/DSP valve (vacuum) after knowing the case is tight. And if I use the sparkplug adapter approach for the case, I always check the plug threads/plug gasket itself while using the intake adapter. Often overlooked, but I've torn my hair out looking for small leaks coming from somewhere that were either the metal plug gasket or plug hole threads. Another good application for the green Loctite, btw.

 

[Dennis Gauge]

Scored a 2.1 Mac (1985-1984 model) the other day for free. Me and the neighbor were talking chainsaws and he brought up how he could not get this saw to not bog while cutting wood. Said other than that, it idled fine and he was tired of trying to tune it. He said he just replaced the fuel lines. I think a little adjustment on the hi carb needle ought to do it. What do ya'll think?

You may have paid too much.

From the looks of it it is a derivative of the MiniMac, which is one of the most disliked models among McCulloch collectors.

 

[95custmz]

You may have paid too much.

From the looks of it it is a derivative of the MiniMac, which is one of the most disliked models among McCulloch collectors.

Well, if "free" is paying too much, it must really be a POS. LOl

 

[heimannm]

I thought the dimensions looked correct but I didn't want to make any assumptions.

The older 10 Series had a much larger O.D. on the seal to match the O.D. of the bearing an fit in the same bore as the bearing.

Mark

 

[heimannm]

The 2.1 is a 300 Series saw, not a Mini Mac. The only Mini Mac that is really hard to work on is the original Mini Mac 6 with the starter housing fixed to the flywheel housing, you have to get the starter pawls aligned just so with the fins on the flywheel to get the engine out and back in again.

The rest of the Mini Mac saws with the removable starter housing are no more difficult that any other top handle saw, exception being the Poulan Micro type which are pretty easy to work on.

Mark

 

[PogoInTheWoods]

I thought the dimensions looked correct but I didn't want to make any assumptions.

The older 10 Series had a much larger O.D. on the seal to match the O.D. of the bearing an fit in the same bore as the bearing.

Mark

I see the Poulan 5300019079 is a substitute for the PTO side 110260. Any chance the Poulan 5300019146 is a substitute for the f/w side 61618? I've not found any pictures of a 471551 that look like a 61618 though the listed dimensions do seem correct. The Poulan 19146 looks right as pictured on a 1 inch grid, but doesn't have dimensions listed.
Tim?

 

[PogoInTheWoods]

And I'm going out on a limb and assuming this is rather excessive end gap? I'm seeing 87854 for a replacement set. And yes, there is a little scuffing there below the port.

I'll shut up now and go work on this thing.

 

[fossil]

I think, but not sure, that the pin in the ring land should figure into the ring end gap, especially in butt end rings. Rule of thumb for end gap rings in a two stroke is
.003/1" of piston diameter. Better to err on the wide side than too tight.
What's the piston look like?
If you want Poge, I have a 471551 seal and I'll mic it for you. Most of the pics you will see of seals on line are not the seal for sale. It's just a pic of some seal.

 

[PogoInTheWoods]

The end gap is nearly 3/32" ~ 1/8". Woulda been nice to check compression before I tore it down except for the broken crank on the flywheel side, but that gap seems excessive. Best price I found on rings so far is $25. Piston looks fine. Haven't measured skirt clearance.

And 10-4 on the seal pics, though ones I've seen of the National 253747 and the SKF CR6119 look like the Mac 110260 whereas the 47155 doesn't look at all like the 61618. Call me skeptical, tho the specs do look like what the 61618 should be as Mark also mentioned. (I don't have one pulled to compare.) Anyway, that's why I asked about the 5300019146 Poulan/Husky seal. Looks like the 61618 and since the 5300019097 is a substitute (though NLA) for the 110260 it seemed possible that the 19146 may work for the 61618....and it's only $2.35 from RepairClinic! It's common to the Poulan 3350,3500, and 3600 fwiw.

Anyway, sorry to monopolize the thread and I sure am grateful for the input. I'm pretty excited about finally getting to my Macs.

 

[fossil]

Anyway, sorry to monopolize the thread and I sure am grateful for the input. I'm pretty excited about finally getting to my Macs.

It's not like people are waiting in line to jump in.