McCulloch Pro mac 510

midnightmaniac

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Looking for help reguarding a old saw my father in law used in the late 70s.He passed away last year and my mother in law wants me to get it running.
The saw is a McCulloch pro mac 510 and not many parts are available.
Started out rebuilding the zama c1 carburetor,replacing the fuel lines and adding a bulb type primer. Got the saw running and after a few seconds it would lose all spark and die.Coil tested bad so i replaced it with a used one as they are no longer available.Replaced the points and condenser with the oregon ignition module.Saw starts and runs but when running at a constant speed it will begin to rev then die. Any help woud be appreciated.Thanks
 

RDA.Lawns

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Sounds like its (carb) either out of adjustment or its sucking air.
 

midnightmaniac

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Ive tried settings from 1 turn out on both needles to 2 turns out.This saw doesnt have a vented fuel tank.Could a leak in the tank cause this?
 

midnightmaniac

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OK,Repared crack in tank.Replaced intake and carb gasket and still no change.It will start,run a few seconds,rev then die.Checked compression and it has 82 psi and 85 with oil in the chamber.
What is the problem with this thing?
 

RDA.Lawns

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Just a thought is the fuel lines swapped to the wrong spot?
 

midnightmaniac

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Tried that too.push the primer in and it would stay sucked it.
Relized last night I was suppose to do the compression check with therotle wide open.I didnt do that.
Latter today I will recheck that.
 

midnightmaniac

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Instaled a new piston and ring.Got a 3 pound increase in compression.
Same result.Its hard to start,runs about 30 seconds.revs and dies.
Where could this be sucking air from?Im at a lost.
 

primerbulb120

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There is NO WAY to correctly add a primer on these units without changing the carb. Could you give me a diagram of how you routed it?

I just restored one of these units, and they really don't need a primer - adjust them correctly and they will start in a few pulls.
 

deck~dragger

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Instaled a new piston and ring.Got a 3 pound increase in compression.
Same result.Its hard to start,runs about 30 seconds.revs and dies.
Where could this be sucking air from?Im at a lost.
Maybe a fuel problem the Mac is not designed for a primer.

There are several areas it could be sucking air. Ran across this article a while back while working on a saw- http://www.madsens1.com/saw_airleak.htm
 
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