McCulloch Pro 10-10 Spark Problems

[ozziechainsaw]

Hi Everyone,

I got given a McCulloch Pro 10-10 last week (photo's attached) for free. I was told that it used to run, but hasn't been running in years.

So after getting it home i decided to have a look at it. First I checked compression. 145 psi cold. Next was spark.......nope no spark. I removed the flywheel gave everyting a clean and had a look at the points while I was there. They were set at 13-14 thou. I'm not sure if that was correct so I reduced it to about 8 thou gap. If it should be bigger or smaller can someone tell me.

So i put it back together and tried for spark again.....NOTHING. I checked everything and I couldn't get the spark plug to fire. So i put a screw driver into the spark plug lead , earthed it out against the body and I got bright blue spark. I put the spark plug back in and nothing. So after 10 minutes of swapping everything in and out, i decided to swap it for another plug, just in case the plug was the problem. 3 different plugs later I still couldn't get spark. But if I put a screw driver into the lead and earth it out I would get spark.

I just cannot understand. Plug in.....Nothing..........plug out and screwdriver in and earthed onto the body.........nice spark...........Can someone help ??????????

 

[ozziechainsaw]

Any idea's anyone ?

 

[frank_]

resistor spark plugs are they ?
and 8" thou sounds too small to me

 

[Old2stroke]

Someone will probably join in with the correct points gap, I seem to recall it being more like 0.012" to 0.015". When you used the screwdriver to check spark, what was the gap the spark had to jump relative to the one in the plug? The amount of voltage require to jump a gag is proportional to the size of the gap. It sounds like you have some voltage, just not enough. Did you clean the points while you were in there? The capacitor on those older saws can dry out and have a serious effect on the quality on the secondary voltage and the only good test is to swap it with another. Another thing to consider is the voltage required to fire a plug in an engine under compression is a lot more than what is needed when the plug is out of the engine so a good test for ignition quality is to see if it will spark a plug outside the engine that is gapped to about 0.080". If it won't, then it probably won't fire a plug in the engine with the correct gap.

 

[Jasonrkba]

Just an idea, I believe a coil from the 600(pm610, 605, timberbear) model will work. If you can find one in the local Craigslist cheap you could steal the coil and be done with the points.

 

[ozziechainsaw]

I might have a look at the capacitor this week and see if I can get some numbers off it and have a look.

If anyone knows the correct points gap for the McCulloch it would also be great to know.

Cheers
Justin

 

[Jasonrkba]

Go to the beg for manuals thread and ask for the service manual and ipl.

 

[rwoods]

Post your question in the MAC stickie thread - lots of knowledgeable and helpful folks there.

Ron

 

[MacAttack]

I set my McCulloch point gaps to .018".

 

[Patrick62]

back in my moped days, we would fiddle with the things, and eventually I learned to take the time, hook up a continuity tester, and get the points to open exactly a mm before tdc. IF the coil and condensor were good they would spark nicely, and run strong. Who knows where the gap was, but IIRC they all looked to be in the 12 to 16 th range...

 

[heimannm]

0.018-0.020" for the point gap. Most likely there is a bad connection between the spark plug wire and the terminal end the plug is supposed to engage, you are making contact when you put the screwdriver up in there. Most of the time the terminal end just pierces the spark plug wire and is supposed to then contact the solid wire in the spark plug lead.

The electronic coil from the 600 Series saw has a different mount that the point coils on the 10 Series saws. There were a few blocks made that would accept either the electronic coils or the points coils but you also need a spacer to allow the coil to mount properly.

Points ignition coil only mount



Point (with the spacer) or electronic



Electronic ignition coil only



Mark

 

[frank_]

resistor spark plugs are they ?
and 8" thou sounds too small to me

if they were resistor type plugs then they have a resistance built in
so if you have a weak spark then it may show an arc until you try a plug