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Timber Bear not starting

forgetaboudit

forgetaboudit

ArboristSite Member
Joined
Sep 17, 2021
Messages
83
Location
Wisconsin
Hey gang,
I've got a McCullough Timber Bear that used to run great. Until I'd run it a while and it would restart if I shut it off.
Now I put a new recoil on it (broke the spring), tried starting and she wouldn't go. Gave her a quick spray of starting fluid and she sputtered for a few seconds. Then I got it started with 2 pulls and she roared to life for about 30 seconds and sputtered and died. Now she won't show anything. Even with starting fluid.
It's got spark, compression is 140psi, exhaust screen is clear, kill switch ohms out fine.
Not sure what else could be the issue.
I even bought a parts saw that doesn't run for 10 bucks to replace the recoil. Now I have 2 saws that don't run...
 
forgetaboudit

forgetaboudit

ArboristSite Member
Joined
Sep 17, 2021
Messages
83
Location
Wisconsin
You're welcome. We are here to help each other and learn from each other. I don't have any suggestions on your saw except for complete fuel system check.

Sent from my moto g(7) power using Tapatalk
That's why I came here. Hoping to get more help and advice.
I did replace the carb about a year or 2 ago. New fuel line, new filter. She ran well after for a little while until the recoil crapped out.
 
Bubster

Bubster

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Aug 22, 2021
Messages
70
Location
WV
A weak ignition coil can make a spark but not always enough to start your saw.Gas in the carb or a teaspoon down the cylinder should make it start.What color is the spark at the plug?
 
forgetaboudit

forgetaboudit

ArboristSite Member
Joined
Sep 17, 2021
Messages
83
Location
Wisconsin
A weak ignition coil can make a spark but not always enough to start your saw.Gas in the carb or a teaspoon down the cylinder should make it start.What color is the spark at the plug?
Interesting...
Didn't actually see the spark on the plug, I plugged in my inline spark tester...
Maybe I should pull the plug and test that way.
 
MacAttack

MacAttack

I love the smell of 2-stroke
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Nov 15, 2019
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Sounds like a weak spark, or not getting fuel. It could also be flooding.

Depending on how old your premix gas is, and if it has ethanol in it, first things I'd try would be dump the gas out and mix up fresh gas, and install a new spark plug.

If it's still a no-go, you need to look at the spark plug to see if it's wet with gas, or dry from lack of fuel. Wet with gas could mean a weak spark or a carb issue. Dry spark plug could mean carb is plugged, inlet needle not opening, or a stiff metering diaphragm in the carb.

Ethanol gas creates a whole list of possible issues in a small carbureted engine, which is why I hate the s--t with a passion.

Also yes, please use a little premix in the intake or sparkplug hole and not starting fluid.
 
Bubster

Bubster

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Joined
Aug 22, 2021
Messages
70
Location
WV
Interesting...
Didn't actually see the spark on the plug, I plugged in my inline spark tester...
Maybe I should pull the plug and test that wa.
A new plug is always a cheap way to solve many problems.But with even just the smell of gas in the cylinder,your saw should pop.Good luck and let us know.
 
Jasonrkba

Jasonrkba

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Are you running non ethanol fuel? If not the fuel lines are probably shot as well as diaphragm. I had a bad coil on one of my timber bears and it ran very erratic. Those are the same coils used on the 10-10 and are getting pricey. If I remember right those have the Q port exhaust and 140 is pretty high.
 
forgetaboudit

forgetaboudit

ArboristSite Member
Joined
Sep 17, 2021
Messages
83
Location
Wisconsin
Non ethanol. The mix I used is a little old as I don't use mixed much.
Is there a way to test a coil? Multimeter and measure output?
Is high compression bad? What would cause it to be high?
 
Maintenance supervisor

Maintenance supervisor

Every 100yrs, All new people...
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Location
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Coil to flywheel gap should be checked, replace the spark plug for cheap insurance.
I often hold the spark plug lead to eliminate the possibility of it being broken, fyi its gonna shock you if it is when you pull the cord. Theres a tiny spring hook under the boot cap that could be making intermittent contact with the wire?
With all that though, if you are seeing spark in your tester the flywheel key could be sheared off and you timing is off.
Those coils RARELY go bad if ever so ....
 
forgetaboudit

forgetaboudit

ArboristSite Member
Joined
Sep 17, 2021
Messages
83
Location
Wisconsin
Coil to flywheel gap should be checked, replace the spark plug for cheap insurance.
I often hold the spark plug lead to eliminate the possibility of it being broken, fyi its gonna shock you if it is when you pull the cord. Theres a tiny spring hook under the boot cap that could be making intermittent contact with the wire?
With all that though, if you are seeing spark in your tester the flywheel key could be sheared off and you timing is off.
Those coils RARELY go bad if ever so ....
I'll look into all that. What's the gap supposed to be?
 
forgetaboudit

forgetaboudit

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Joined
Sep 17, 2021
Messages
83
Location
Wisconsin
Replaced the spark plug, and the spark looks a little better, but still no spark unless I pull hard. I dropped mixed gas into the cylinder, replaced the plug and pulled till I was blue in the face. Not even a sputter.
I don't understand... Has fuel and spark, it should burp a little.
I did this with the donor saw and came up with the same results...
 
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