I'm checking a saw for a friend. Compression is only about 110 and there is no spark. Kill circuit is not grounded, tried another plug, no spark. Coil to flywheel gap is. 0.010" I get no ohm reading from the plug wire to anywhere on the coil - both high and low ohm ranges. There was a LOT of sawdust packed in the starter/fan area. I'm thinking it overheated and killed the coil/module. I see a darkened area on the back of the coil and a crack - see photo. Is coil failure common for this saw? I haven't run a pressure/vac test yet - waiting to see if a coil is available and price. Is the coil used on any other brands like Poulan?
Help - Pro Mac 10-10S No spark
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A 610 or variant coil will work but needs the lead shortened. The S is a mean saw and worth saving. Very common coil should be easy to find. Hows the cylinder? 110 could be a worry
Do you mean the spark plug lead? No problem to shorten it.
It was hard to get a good look at the piston since the exhaust is on the bottom but it looked fair - some streaking but no definite scoring. I was surprised compression was so low. I tested a Homelite 4-20 and XL12 he gave me and got 125 on both. Hoping to get it running and recheck compression.
It was hard to get a good look at the piston since the exhaust is on the bottom but it looked fair - some streaking but no definite scoring. I was surprised compression was so low. I tested a Homelite 4-20 and XL12 he gave me and got 125 on both. Hoping to get it running and recheck compression.
Yeah plug lead. Any mccinderblock saw. And all electronic 10 series too so should be easy enough to suss 1 out. It probably still run fine a bit down on psi hell I have a 7-10 that's missing chrome and scored bad but its a great running saw infact 1 of my best starting saws I have.
I've come across a few bad plug wires on the 10 series saws. Unscrew it from the coil. You might have to take something and go around the plug wire socket on the coil to loosen the epoxy they set it in. Go slow as the plastic can be fragile.
If the saw has been sitting for a long time the cylinder might be dry. Put a bit of oil through the plug hole and roll it over a bunch of times a check the compression.
If the saw has been sitting for a long time the cylinder might be dry. Put a bit of oil through the plug hole and roll it over a bunch of times a check the compression.
Ive never seen a bad coil on one so definitely not common, seen plenty of bad plug wires( stepped on alot) .I replace them with metal core accel racing wire.
Is the decomp button open/pushed slightly? I've had them get pretty dirty and soaked them in mean green ,sealed alot better .
Is the decomp button open/pushed slightly? I've had them get pretty dirty and soaked them in mean green ,sealed alot better .
Thanks, hadn't thought about the decomp, not being familiar with the saw. I thought about the plug wire - will replace it and try again. Believe it or not, the 4-20 and XL12 fired right up with a prime.
Xl-12 is a pretty solid saw.
You should consider checking/ posting on the McCulloch thread in the stickys and the Homelite thread . Lots of helpful people in those threads.
You should consider checking/ posting on the McCulloch thread in the stickys and the Homelite thread . Lots of helpful people in those threads.
As noted, any 10 Series electronic coil or 600 Series coil (all are electronic) will work but it you get no reading from the spark plug lead to ground I would suspect the wire is broken or disconnected.
Most of the time the spark plug wire will not simply unscrew since they are glued in place. Once they twist off I use this left hand hollow bit to clean out the broken off wire out of the hole. The bits are available from Rockler and are intended to be used to remove wood screws with the Philips or slot stripped out or broken off. https://www.rockler.com/screw-extractor
You should be able to measure 2.5-3K ohms from the spark plug lead to ground.
Mark
Most of the time the spark plug wire will not simply unscrew since they are glued in place. Once they twist off I use this left hand hollow bit to clean out the broken off wire out of the hole. The bits are available from Rockler and are intended to be used to remove wood screws with the Philips or slot stripped out or broken off. https://www.rockler.com/screw-extractor
You should be able to measure 2.5-3K ohms from the spark plug lead to ground.
Mark
Thanks Mark! You do mean 2.5K to 3K ohms, right?
Yes
Changed plug wire - no spark. Good call on the decomp valve - it was in. Now compression is 140. Will look for a coil.
Good news on the compression. Wicked saw the S hope you get her running.
My S lives inside an older lighter chassis and its my go to saw
My S lives inside an older lighter chassis and its my go to saw
Put the replacement coil on and got weak spark, saw wouldn't fire. I noticed the spark was better the faster I pulled the starter - higher rpm. Kind of acts like weak flywheel magnets but they feel real strong. I dropped the coil-to-flywheel gap from .010 to .005 and spark is better but saw still won't fire. I'll try replacing the plug wire tomorrow. Any other ideas?
How many fins/blades does yur flywheel have? Pictures would help at this point.
Never mind I just looked at the first post.
The distance between the coil and the magnets on the flywheel are very important for the ignition system to fire correctly
The rule of thumb is to loosen the coil and place a business card in between the coil and flywheel, then rotate the flywheel while holding the card when the coil sucks down to the magnets tighten the bolts that hold it, remove card. Then rotate the flywheel to make sure there's no interference.
If the gaps to small thats also bad.
The distance between the coil and the magnets on the flywheel are very important for the ignition system to fire correctly
The rule of thumb is to loosen the coil and place a business card in between the coil and flywheel, then rotate the flywheel while holding the card when the coil sucks down to the magnets tighten the bolts that hold it, remove card. Then rotate the flywheel to make sure there's no interference.
If the gaps to small thats also bad.
That's how I've always done it - with a card that mics to 0.010. When I noticed the spark was stronger at fastest rpm while pulling, I reduced the gap to .005 and spark improved but still not firing, even with a prime. Now that I think about it, if there was enough sawdust blocking airflow and causing high heat, maybe that reduced the strength of the magnets but again, they feel as strong as any I've worked on.
Strange. This is the time I'd be selecting a runner and flog its parts until you find what it is.
Wish I had one. Pretty much has to be flywheel or plug wire on the used replacement coil. Try again tomorrow. This is why I prefer points ignition, never had one I couldn't get started.
