OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Chainsaws and Concrete Cutters McCulloch Chainsaws Mcculloch pro Mac 700 won't start

G'day! I've just scored a pro Mac 700 and despite giving it some tlc I'm yet to get it roaring. It's got good spark, fresh fuel, good comp. , clean air filter etc but I can't get it to fire up. After about 6 pulls fuel is coming out the muffler. I've had the carby off and taken the top and bottom plates off for a squizz and it looks clean and ok. The plug is pretty wet when I pull it out. I'm wondering if it would be worth putting a carby kit through it? How much should I be paying for one of them?
Any other ideas?
I've got to get this beast going A: because I've got trees to cut down and
B: my old man always said " don't buy a McCulloch - they're useless, only good for boat anchors..." and I can't stand the " I told you so's"!
Cheers, Ben.

Hi Ben, welcome to Outdoorking.

There are three elements in getting an engine to run: spark, air/fuel mixture, and compression. If it doesn't run, at least one of the three isn't happening. You have said you have spark, but you have wet plug and fuel coming out of the exhaust. Unless you are wrong about the spark, the explanation that fits the symptoms best is flooding.

Flooding with chainsaw-type carburetors is usually due to carburetor settings or carburetor diaphragm. If your saw is really old and sick it could be that it just has no compression left due to bore scoring and ring wear, but you said it has good compression. Hence, if you are sure it has spark, you need to overhaul the carburetor. The most common single cause of flooding in that style of carburetor is the metering lever being set too high. This happens after an amateur has tried to fit an overhaul kit and has failed in his/her efforts. The next most common cause is dirt under the inlet needle valve. Neither of these faults necessarily requires replacement of diaphragms. However you may need a kit anyway if the existing diaphragms have been badly installed.

If you tell us what make and model of carburetor your saw has, we can try to find you a free on-line manual which tells you in detail how to overhaul it.

Another issue could be that it will spark ok out of the motor but when you ask it to spark in the extra pressure of the chamber it wont.


Try a new spark plug, if that dont work, try another new spark plug. Never trust a spark plug.
A bit hard without it running but you could try starting it in a dark spot and see if the spark is tracking anywhere.

Id do that first then look into the carb.

Hi Ben, and a warm welcome to the forum. Its great to have you aboard.
Can you also please post your Pro Mac model number from the ID plate affixed to your saw with also the suffix letter after the number; (suffix letters denote the variation in parts or assemblies in manufacture). From some research, your carburetor should be OEM Part No 87666 which is a Walbro SDC-44-1....Could you please check and see?

Once again, Ben, to the OutdoorKing forum.

Great! Thanks guys. I'll get a new plug and try that. When I get a chance I'll check the carby details. I think it's a walbro D10-SDC.Definitely looks like it's flooding.
The carby manual would be great. I'll let you know how I go.
Cheers, Ben.

Ok it's a McCulloch Pro Mac 700, Model 600061, Serial A11 10237, Walbro SDC carby # 3-77 44A.
Cheers, Ben.

Hi Ben, here is a service manual for Walbro diaphragm carbies...Click HERE
Hoping this helps, mate.

Here is the specific manual for the Walbro SDC:

http://wem.walbro.com/distributors/ServiceManuals/SDCSeries.pdf

SUCCESS! I pulled the carby apart again and found a speck of dirt under the needle seat. Cleaned it up, put it back together and she started first pull! Works a treat. Got a new plug for it too and a chain file so I'll sharpen it up tonight and give it a big test tomorrow on some big stringybarks.
Thanks for the help guys, I'm sure the manuals will come in handy.
Cheers, Ben.
Ps. I may let Dad borrow it... If he's lucky:)

Well Ben, you've contributed a tick to the second-most-popular cause of flooding. Deejay or Ty, if you read this, would you mind closing the thread? Thanks.

Thanks for letting us know Ben.
As this thread is now complete, I'll close it.