Mac 10-10a idle issue

[Hammer79]

I have a newly acquired old McCulloch that I can't get to idle. It has new fuel line and carb kit. It fires right up whether cold or hot it just shuts off as soon as I let go of trigger. The carb is a McCulloch brand (looks exactly like walbro sdc). The thing that throws me is that there is no idle screw? If I just move the throttle a tiny bit it will run forever. I don't know how to adjust it without a idle needle. Any help would be appreciated.

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[Warped5]

You don't have an idle speed screw on the carb .... interesting. Does it have H and L screws? A photo or two might help.

Some of the 10 Series saws also had an adjustment screw on the trigger itself. Look underneath.

 

[Hammer79]

It has high and low. Nothing on trigger. Here are some pics of it. I thought maybe the isle screw was gone but I don't see a hole that is labeled with an i or anything.

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[Warped5]

Ah ....

Looking to me like that carb is not original to the saw.

None of the bosses in the side of the carb box have been drilled/tapped ... that carb looks to have been equipped for just that.

 

[Hammer79]

Ok, that could make sense. I got 2 10-10's together and neither would run. The other saw is older and had a trigger idle screw. I bet someone tried swapping them. The other one had a walbro sdc with an idle. I'm going to switch them and try again. Thanks!

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[Hammer79]

Switched carbs and she runs an idles. Put her all back together and one pull and the rope broke... It never ends. Haha. Anyway to tell how old the saw is?

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[Al Smith]

If I get a chance I'll try to determine age from the number plate shown in one pic .Quite frankly I'm not certain exactly how the idle was set on that model because many methods were used .Just the IPL's on the 10-10's are many .Remember this model covered something like a span of 25 years or so of production run . Mark H could probably tell the info from memory but I'll have to glean the IPL's myself . I might have a right hand start in the shed buried in that mess of chainsaws ,weed wackers,blowers ,small engines and other assorted treasures.

 

[Al Smith]

So far from an IPL dated June 1970 this model of 10-10 used a variation of a model SDC-1 Walbro which most likely was rebadged with a McCulloch logo .From that IPL it used an idle screw attached to the carb .
I wasn't able to get specific the exact manufacturing date .
It was not and still is not unusual for chainsaw makers to have the carb builder make models with their brand embossed .I've got some with McCulloch and some with Stihl .