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McCulloch Mini and Small CC Chainsaw's

PogoInTheWoods

PogoInTheWoods

Don't forget about the alligators...
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Reportedly in the Area
May also want to check if someone else already did a plug lead replacement somewhere along the line and gotten silicon or sealant on the post itself. That would certainly create the possibility for a bad or intermittent secondary reading.
 
MacAttack

MacAttack

I love the smell of 2-stroke
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Hi Mark,

I'll try to get a picture, it looks like a smooth "spike" in the coil, no signs of threads. When I originally removed the plug wire I twisted it from what I had read about these coils, as soon as the old epoxy broke free it slipped right out. There are also 3 ridges cast into the opening for the wire that appear to keep the wire from rotating in the coil.
Unfortunately, I tested the coil by putting meter probe directly on that metal spike, and there is no continuity. When it did have continuity, the reading was around 8.5K ohms, where all my known good coils are closer to 7.6K, so it was probably on its last legs.
 
MacAttack

MacAttack

I love the smell of 2-stroke
Joined
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Messages
1,249
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May also want to check if someone else already did a plug lead replacement somewhere along the line and gotten silicon or sealant on the post itself. That would certainly create the possibility for a bad or intermittent secondary reading.
Good idea but no sign of that, I'm testing the bare metel spike in the coil and she's dead... Fortunately I have a spare coil so the saw is going back together!
 
MacAttack

MacAttack

I love the smell of 2-stroke
Joined
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Messages
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Going to take a hiatus for a while, maybe come back to this in the winter. I really thought the MM25 was fixed, even cut a limb off a tree...then it flooded again. Makes no GD sense, once the carb is primed it will not seat the needle. New diaphragm, needle is perfect, it just won't stop flooding. To add insult to injury, while I was trying to get it restarted it popped when the crank was almost stopped, crank went backwards and it exploded the recoil spool which was already previously repaired.
So...Im done for now. Maybe in the Winter I'll come back to this. Thanks for all the help! I still have 2 sweet running 10-10s, the SP40, and my old reliable MM30.
 
MacAttack

MacAttack

I love the smell of 2-stroke
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@heimannm you had once posted a clever repair to the cracked Mini Mac recoils where you installed a metal band around the plastic neck that holds the metal prong. Do you have any information on the size of the metal pipe / band that you uses or where you sourced it? Now I'm concerned my remaining plastic/metal recoils are going to end up blown apart....
 
MacAttack

MacAttack

I love the smell of 2-stroke
Joined
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Messages
1,249
Location
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Now I'm not so certain it's an issue with the inlet needle. When the MM25 sits it doesn't leak gas like it did when the diaphragm was in backwards. So now it seems more like an issue with something else, or I just managed to flood it. But it was running and warmed up when it flooded...
The metering lever was level with the carb body, hi and lo needles were at 1 turn out, what am I missing?
Is it possible the new Welch plug I installed over the check valve is leaking? It seemed to be a good fit but didn't snap in as hard as I expected, just some finger pressure and I heard it snap. Then I proceeded to peen the center into a dimple. Is it common for them to leak and cause flooding?
Running out of ideas, but I might try a new sparkplug and start out at 1/2 turn on the needles and see what happens...
 
MacAttack

MacAttack

I love the smell of 2-stroke
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That would be great, thanks!

I have 2 pulleys in which the plastic cup is entirely shattered. I measured the metal "pawl" with a calipers and it's just under 1" diameter. I'm going to search for SOMETHING with a 1" ID that could somehow hold the metal pawl and attach ro the body of the pulley.
These NLA parts force you to get creative...
 
heimannm

heimannm

Tree Freak
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Dike, Iowa
I recently bought an aluminum one with a brass bushing off Ebay plus one metal plastic one that I already repaired and one metal plastic one that needs to be repaired.

Mark
 
MacAttack

MacAttack

I love the smell of 2-stroke
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Have you had problems with welch plugs leaking in the MDC carbs? Based on what I've read a leaking welch plug can cause the rich running / flooding I am dealing with. I have no idea if I did a well enough job installing this one, it was a stens plug that I had to file down somewhat to the correct thickness. It went in with finger-pressure with a snap and I battered it down somewhat with a flat punch.

I'm strongly tempted to try sealing it with something like Seal-All.
 

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Manic84

Manic84

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Now I'm not so certain it's an issue with the inlet needle. When the MM25 sits it doesn't leak gas like it did when the diaphragm was in backwards. So now it seems more like an issue with something else, or I just managed to flood it. But it was running and warmed up when it flooded...
The metering lever was level with the carb body, hi and lo needles were at 1 turn out, what am I missing?
Is it possible the new Welch plug I installed over the check valve is leaking? It seemed to be a good fit but didn't snap in as hard as I expected, just some finger pressure and I heard it snap. Then I proceeded to peen the center into a dimple. Is it common for them to leak and cause flooding?
Running out of ideas, but I might try a new sparkplug and start out at 1/2 turn on the needles and see what happens...

So it loaded up and flooded out when it was idling? And do you have the ability to do a pressure test on the carb?
Also, yes, a leaking welch plug can cause it to load up or flood out. I think a big clue is if it can idle with the L speed needle all the way in. That tells you if a plug is leaking.

Now before you call up an exorcist for the Mini Mac From Hell or get all dejected, watch this short little video.
Notice how he snaps the plug in with his finger and goes in a bit of a circle with the punch. You don't have to go ape on the thing, but you must be careful and firm.
I do have confidence though that you got it right and it's not the plug.



Honestly though, I have never seen a leaking welch plug before, so I could not tell you exactly what to look for. Every rich/flooding issue I ever saw was either adjustment or inlet needle/lever/spring related. I'd really take a hard look at the lever to see if it is set right (might be just a tad high) or is binding somehow, and if the inlet needle is sealing right.

Good luck MacAttack! :)
 
Manic84

Manic84

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Well, how's this for a "project"? (Sorry about the pictures, I thought they were better)

It does pull over, has no/little mag-rot and has a little compression but...

The bar, sprocket and chain are rusted solid and refuse to move. I had a real time trying to get them off in the first place.

I gave it a quick wipe down, but it was far worse off and was/is caked with this odd oily, sticky, sap-like dirt mixture that does NOT want to come off. I can only imagine the inside of the case...

Water got into the oil reservoir and maybe the pump, and seems like it went into the engine itself. (white viscous sludge)
Water also calcified on the carb... I wonder what the inside of it looks like... fun times ahead.

Every bolt and screw is either frozen or stuck, and the spark plug refused to budge. Again, there is hard set rust in all the convenient places.

A quick test determined that it has no spark on account of it being left "On" for... God knows how long. The kill switch was difficult to move as well. Might just be a simple points problem... hopefully.

Both of the choke and throttle butterflies are also stuck and can’t be moved at all. Same story with the L and H speed needles and the idle speed screw. And it does have the choke lever (slightly cracked though), I just took it off for now... That was also a royal pain in the ass.

Updates will be few and far with this one. I have no high expectations for this saw and am content with cleaning it off and putting on a shelf for the rest of its days. Maybe I'll do a light restore at least on the bar just to make it look better before putting it up... Maybe.
 

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Mnmacguy

Mnmacguy

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Have you had problems with welch plugs leaking in the MDC carbs?
Not sure if this is any help to you MacAttack, but I saw this info in my Walbro stuff and thought I'd post it.

6c3a7d7a4c57194349d337480c10b5e9.jpg
2a9f59742dd4f7f0a2bd823c7d6d2c80.jpg


Sent from my moto g(7) optimo maxx(XT1955DL) using Tapatalk
 
MacAttack

MacAttack

I love the smell of 2-stroke
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Manic84 thank you for the advice! I am actually going to try a complete carb swap with another MDC that I rebuilt and see what happens.

That MM30 looks like a sad story....you'd almost have to assume the internals are junk. But it looks like it has some good parts!
 
MacAttack

MacAttack

I love the smell of 2-stroke
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I decided to try the process of elimination...and what better way to eliminate different carb issues than to eliminate the carb altogether?
Full carb swap with an MDC-2 that I have from a MM35. I did the fuel-line test by mouth on the High speed circuit and the check valve seems to be intact and working!
Completely different rebuild and gaskets and diaphragms, only part I transferred is the metering lever. If this one floods, I'll know for sure i need to lower the lever.
If you look closely at the new carb, you can faintly see some type of sealer on the Welch plugs, I am guessing nail polish or some type of lacquer?
The engine was very flooded, clearly something was not right.
I can also swear that I can hear some tiny bit of something rattle around inside the engine when I flip it around, like a tiny piece of carbon or something...like REAL tiny. I figure it will just get digested and spit out the exhaust. I sure as [email protected]# ain't taking it apart.
 

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Manic84

Manic84

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Hope it works out and you get to unleash the Mini Mac!
I'm a little bit curious about what that rattle could be though.

As for the Mini Mac 30, yes it could be a sad story... but the story isn't over, so we'll see how it goes for the saw. :D
I can tell you though that this saw will not be used for parts.
 
Manic84

Manic84

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Here's a small update on the Mini Mac 30.

The coil lead was dried out and broke apart as I was disassembling the saw. I replaced the lead with a spare one I had.
The points were rusted/corroded and burned and needed to be re-gaped. I went at the points with 600, then 2000 grit sandpaper and cleaned them. The saw now has spark.

The carb's needles were frozen/stuck. After applying penetrating oil to everything, the needles and everything else move freely.
And the inside of the carb is in remarkably good shape. And the shafts are finally free.

Clean up on the saw has begun and is going well.
The inside of the cylinder is very clean, with no noticeable marks. I do have some apprehensions about the saw, but I am cautiously optimistic about it.

With the all the major items out of the way, I can take my time with the saw now.
 
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