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McCulloch Mini and Small CC Chainsaw's

heimannm

heimannm

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3200? 3214? 3216?

Post a photo to verify which one you have. The 3200 models are not exactly impressive but they will cut some wood. Usually they will need fuel lines, primer, and the oil line from the tank to the pump.

Mark
 
gumneck

gumneck

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Those chinese kits never have it right, the weak point is always the needle, so only the gaskets seem to be worth anything. And that check valve and screen... wow. Did you pull the brass retainer out or were you able to just fish out the valve? Does the rest of the saw check out? (spark, compression, no air leaks etc.)

I very much believe that these saws are very easy, and don't need much to get back up and running.
Most of the time all these saws really need is: fuel line, the check valve, the welch plug and the diaphragms and gaskets-- that's really it. I don't see many people removing the 1/2 plug. They usually just shoot carb spray down the low needle to flush out anything stuck in there. You already have the gaskets, so cut the cost and just reuse the original needle. A lot times you really don't need to replace it as long as the tip isn't deformed and it's still flexible. Now if the needle is completely shot, then you'll have to get the Walbro kit since no aftermarket one really seems to get the needle right.
The saw has consistent spark, starts easy on direct inject mix. Haven't done a vac/press test but will. With asking about pulling "brass retainer", I pulled a small shiny chrome circlip to get to the valve parts(seems like I have dozens of those clips from carb kit parts I've never had to use).
Does the brass retainer screw out or pull out? Once I get the check valve parts and 2 welch plugs I can button up the carb on this. Then I'll do a v/p test before putting it back together.
 
gumneck

gumneck

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How did you successfully remove the welch plug? I will need to do the same soon.
I tried a spring loaded center punch I picked up specifically for this job. Just a harbor freight under $5 tool. I pushed that punch about 20 times on each one and although I put a nice dent in it, I couldn't get them to pop out. There some YT videos showing guys doing it but I suspect the carbs weren't nearly 50 years old and never removed before. Anyway, I ended up using a tiny drill bit, held the carb up on its side and drilled at an angle to the dents I put in the plugs with the punch. I did nick the carb under the plug but nothing near any thing crucial. Then, with a small pick just popped em out. Take your time if you have to drill and just barely get through the plug, in fact stop just before penetrating the plug. Then use a pick to get through.
 
Brushswamper523

Brushswamper523

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any one know a good kit for a mdc carb. I am leary of some kits. I need the whole kit needles, welch plugs, screens, and so on. Some one left fuel in it and we'll you know how that goes. I bought a chem dip for the carb and plan on soaking it and cleaning it all that way. I know I have posted the pick before and was told to get a k1 kit but which kit is full that I need to do this all in one shot. model # of carb is in the pic
 

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Manic84

Manic84

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The saw has consistent spark, starts easy on direct inject mix. Haven't done a vac/press test but will. With asking about pulling "brass retainer", I pulled a small shiny chrome circlip to get to the valve parts(seems like I have dozens of those clips from carb kit parts I've never had to use).
Does the brass retainer screw out or pull out? Once I get the check valve parts and 2 welch plugs I can button up the carb on this. Then I'll do a v/p test before putting it back together.

That’s good to hear, and doing a pressure – vacuum test will answer a lot of questions at once.
The retainer is a pull out, so either a blunted wood screw or small tap can easily pull it out.
However, pulling it out is unnecessary. If the retainer is still there and you got the old valve out with a pick, you can get a new one in the same way. Just shoot some carb spray down there to clean out any gunk or bits of the old valve and you're set.

If you do want to pull it anyway, just know that the replacement kit is $10+ each, and does not include the correct welch plug.
If you have spare kits, then you can you use the circlips and screen included in them since that is part of the replacement kit anyway. You can even make the check valve from the spare fuel pump diaphragms from the kits as well. (Buna or Teflon, it's your choice)
The cheapest, most consistent way to make a valve is using a spent .22 casing as a punch. It is just an effective time and money saving option.
 
Manic84

Manic84

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any one know a good kit for a mdc carb. I am leary of some kits. I need the whole kit needles, welch plugs, screens, and so on. Some one left fuel in it and we'll you know how that goes. I bought a chem dip for the carb and plan on soaking it and cleaning it all that way. I know I have posted the pick before and was told to get a k1 kit but which kit is full that I need to do this all in one shot. model # of carb is in the pic

Genuine ones are the best way... but man are they expensive at $25 - $30+ each. The K1-MDC has the needle, plugs, screen and clip, but I don't think they include the check valve anymore. While the D1-MDC just has the gaskets and diaphragms, which are available from the aftermarket. (stens or rotary) Now there is still a cost effective way to get it all done at once, but there are steps to take first.

The chem dip should dissolve any gunk in the carb so you won't have to worry about that too much, but what type of dip did you get?
 
Mnmacguy

Mnmacguy

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any one know a good kit for a mdc carb. I am leary of some kits. I need the whole kit needles, welch plugs, screens, and so on. Some one left fuel in it and we'll you know how that goes. I bought a chem dip for the carb and plan on soaking it and cleaning it all that way. I know I have posted the pick before and was told to get a k1 kit but which kit is full that I need to do this all in one shot. model # of carb is in the pic
I would go with a genuine Walbro kit too, K1-MDC. It's the most complete MDC rebuild kit I know of. The cheapest genuine Walbro kit I found was $16 on Ebay. Still too expensive in my opinion but is your best bet.


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Brushswamper523

Brushswamper523

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Genuine ones are the best way... but man are they expensive at $25 - $30+ each. The K1-MDC has the needle, plugs, screen and clip, but I don't think they include the check valve anymore. While the D1-MDC just has the gaskets and diaphragms, which are available from the aftermarket. (stens or rotary) Now there is still a cost effective way to get it all done at once, but there are steps to take first.

The chem dip should dissolve any gunk in the carb so you won't have to worry about that too much, but what type of dip did you get?
I got this dip. I read alot on it and it says it is safe. I don't mind buying and little more pricey kit as long as it makes the saw run well. I plan on using my saws. There isn't any point in fixing the thing if it isn't being used. My opinion. I would like to fix all of it however that looks is what I would like to do. You guys know way more than me when it comes to Macs. Most people I talk to say let them die and buy a new saw and I don't really like that answer.
 

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Manic84

Manic84

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I got this dip. I read alot on it and it says it is safe. I don't mind buying and little more pricey kit as long as it makes the saw run well. I plan on using my saws. There isn't any point in fixing the thing if it isn't being used. My opinion. I would like to fix all of it however that looks is what I would like to do. You guys know way more than me when it comes to Macs. Most people I talk to say let them die and buy a new saw and I don't really like that answer.

That stuff seems to work great on carbon, but I've not seen what it does with varnished fuel. I can't imagine any ill effects or it not working. And if the valve isn't included in the kit, just make your own. That alone is the main problem for the MDC.

If you ever need help or have questions, just ask around here. You'll never find a more knowledgeable group than the good-natured guys on the thread. (and we're all mini mac nuts!) :)
 
Brushswamper523

Brushswamper523

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That stuff seems to work great on carbon, but I've not seen what it does with varnished fuel. I can't imagine any ill effects or it not working. And if the valve isn't included in the kit, just make your own. That alone is the main problem for the MDC.

If you ever need help or have questions, just ask around here. You'll never find a more knowledgeable group than the good-natured guys on the thread. (and we're all mini mac nuts!) :)
Awesome man. Appreciate the help. Going to order the kit tomorrow off ebay. Fingers crossed i will get what they say it is
 
Manic84

Manic84

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The MDC Isolated Pressure Test Experiment

How do you pressure test an MDC carb? Usually to do that, you have to reassemble the whole thing... right?
Maybe not anymore. I’ve figured out a way to test an MDC carb without having to reassemble the whole thing and kill two birds with one stone.

A while back, I had gotten an assortment of those cheap 4' fuel lines that are sold on the bay or amazon as way to test things since I didn’t want to use any of the good line I had. At only $5 it wasn’t a bad investment. While I used most of the sizes available, the one I thought was the most useless was the 5/64 x 9/64 since it was too small… but it does have a use!

After getting tired of disassembling then reassembling the carb just to see if either the metering lever wasn't set right or if the needle wasn't sealing right, I started looking at the carb a bit more closely. The MDC has a small hole next to the inlet needle that is part of the fuel inlet circuit. It runs in a sort of "U" type shape.

Circuit.jpg


For a more exact Idea of where it is one the carb here is a better reference from the IPL.

The Spot.jpg

So I cut the line at a steep and short angle and then trimmed it a bit.
Then by twisting it into the opening, the line wanted to kink into a tight "L" allowing you to push it in past the cut, and seal up the passage to the inlet needle. Now you can pressure test the carb. You can check if the needle is sealing right, metering spring strength, pop off and if the needle seals after pop off, and also check the metering lever height all in one go.

The metering lever should be flush with the base of the carb. The way I tested for the height was with a minimum of 6 - 9 psi on the tester, then I just ran a straight edge across the body of the carb. If the lever is set too high, the pressure will bleed off. If the lever is set too low, the straight edge won't even touch the lever. The lever should be set just right so that the straight edge barely touches and actuates the lever, but not lift the needle or release the pressure. And with everything exposed, you can make adjustments on the fly.

Since the circuit setup is the same for the Zama M1 -M7 carbs, the process should be the same. (if not, please correct me)

While I haven’t seen anyone mention or do this to an MDC, I’m hesitant to call this method my own since others have done the same to other carbs. I would argue though, that this way is a lot more stable at holding pressure than using the cone adapter method I've seen.

I’ve always heard that to pressure test a MDC you had to reassemble it, and if something was wrong, you had to disassemble it over and over again until you figured out the trouble. I’m not the first one to do something like this. I think that so far, it's a better, time-saving way to test everything at once.

M
 
Mnmacguy

Mnmacguy

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The MDC Isolated Pressure Test Experiment

How do you pressure test an MDC carb?

M

Thanks for the well written and detailed write up! I haven't got into pressure testing carbs yet but will definitely reference this when I have my next carb to clean/rebuild.

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Mnmacguy

Mnmacguy

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Going to order the kit tomorrow off ebay. Fingers crossed i will get what they say it is

If your K1-MDC carb rebuild kit doesn't include the check valve parts, here is the part numbers for them if you plan to replace them.

McCulloch 83758 or Walbro 86-523

The mcculloch kit doesn't include a welch plug and the walbro kit includes the wrong size welch plug (I think) so hopefully the kit you ordered has the right sized one included.

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PogoInTheWoods

PogoInTheWoods

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Considering 99% of the problems with MM's are the carbs, and considering how many of them are still out there with nothing else wrong with them except maybe fuel lines, you'd think someone would be re-popping them by now, or at least re-popping a quality kit at a decent price. Same with fuel lines.

This is insane.
 
heimannm

heimannm

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I am in the process of moving everything from my home shop/garage to my new building. I have moved most of the NOS parts that were in small parts bins, etc. so today I decided to get the rest of the small saw stuff out of the attic.

20210114_180010.jpg

This does not include the parts saws still in the attic, between MM, PM6, and 300 Series saws there may be 20-25 units left...and a few more boxes with parts. I really didn't realize how much stuff there is up there.

Mark
 
Mnmacguy

Mnmacguy

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Considering 99% of the problems with MM's are the carbs, and considering how many of them are still out there with nothing else wrong with them except maybe fuel lines, you'd think someone would be re-popping them by now, or at least re-popping a quality kit at a decent price. Same with fuel lines.

This is insane.
I haven't run across any carbs that take that costly special hose with the flared end yet. Just been lucky so far I guess. I'm able to use standard 1/8id x 1/4od fuel line that is much cheaper.

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