pafire
ArboristSite Operative
What do I need to check on this saw. It has good compression and after pulling the muffler there is no scoring on the piston or cylinder. Just need to give this saw some spark to run. Anyone have any ideas on this saw.
Homelite C-7 with no spark
- Thread starter pafire
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JohnL
Addicted to ArboristSite
No spark? Easiest things first, check the kill switch, check for spark with kill wire disconnected from it, if that gives you spark bad switch. No change, next thing to check is the points under the flywheel. If they look bad, try filing them to clean them up. After that, coil.
If your not talking about the ignition when you say "spark", that is it just won't fire, try putting a teaspoon of fuel mix directly in the cylinder via spark plug hole, if it will fire, fuel delivery issues.
If your not talking about the ignition when you say "spark", that is it just won't fire, try putting a teaspoon of fuel mix directly in the cylinder via spark plug hole, if it will fire, fuel delivery issues.
GPH85
ArboristSite Operative
If you indeed have no spark, the most common item to go bad, as far as the ignition system goes, is the plug wire comes loose from the ignition coil. As for the rest here are a few usual simple test to test the rest of your ignition system. All you need is a ohm meter of some sort. In these pics I used a very old cheapo that I have here in the house to setup and make sure all connections are secure when I redo my own ignition systems.
A good ignition coil should read around 8 K ohm's as shown testing from the leads to the tip of the plug wire... Now in the second pic in order to perform this test in this method, you must have a good set of points, otherwise it could read OFL when in fact you could have a good coil. In this pic I'm bassically reading the resistance of the entire ignition system --- starting at points, back through the coil and finally to the tip of plug wire...
Then to test your points... You will need to remove your ignition coil and condensor leads to perform this test. You should have nearly no resistance with the points closed. If open or high, you will need to clean them and retest. Then with the points open your meter should read infinate or OFL... Even though you can't really tell it my meter is blinking 100 which means infinate on this particular meter.
Hope this all helps
A good ignition coil should read around 8 K ohm's as shown testing from the leads to the tip of the plug wire... Now in the second pic in order to perform this test in this method, you must have a good set of points, otherwise it could read OFL when in fact you could have a good coil. In this pic I'm bassically reading the resistance of the entire ignition system --- starting at points, back through the coil and finally to the tip of plug wire...
Then to test your points... You will need to remove your ignition coil and condensor leads to perform this test. You should have nearly no resistance with the points closed. If open or high, you will need to clean them and retest. Then with the points open your meter should read infinate or OFL... Even though you can't really tell it my meter is blinking 100 which means infinate on this particular meter.
Hope this all helps
metalspec
ArboristSite Guru
+1
I'd put my money on the points.... Had to clean the points on pretty much all of my old Homelites when I got them...
pafire
ArboristSite Operative
replaced the sparkplug wire end --no spark at the plug
disconnected the kill wire from the switch - no spark at the plug
cleaned the points and reset to 0.15 - no spark at the plug
This is when I noticed the coil is kinda soft and mushy.
disconnected the kill wire from the switch - no spark at the plug
cleaned the points and reset to 0.15 - no spark at the plug
This is when I noticed the coil is kinda soft and mushy.
GPH85
ArboristSite Operative
The ignition coils on these saws are kinda mushy from age and some rubber deteriation. Doesn't mean they are bad...
Have you ohm'ed out your ignition components yet? Checked where the plug wire goes into the coil?
The C5G I'm currently restoring was put aside into storage because of a bad ignition system. All that was wrong was that the points were constantly grounded, didn't matter whether they were open or closed. I recommend ohming out everything to see what you really need.
Have you ohm'ed out your ignition components yet? Checked where the plug wire goes into the coil?
The C5G I'm currently restoring was put aside into storage because of a bad ignition system. All that was wrong was that the points were constantly grounded, didn't matter whether they were open or closed. I recommend ohming out everything to see what you really need.
pafire
ArboristSite Operative
Finally got the time to check the ignition.
With my meter set on the 20k ohm scale I'm reading 8.48 ohms from the tip of the plug wire to either of the wires coming from the coil. Checked the points and they are not grounded. checked the on/off switch and it is not grounded. I do show continuity between the two wires from the coil. Also tried different sparkplugs. The flywheel magnets appear to be strong.
Still no spark at the plug.
What am I missing
With my meter set on the 20k ohm scale I'm reading 8.48 ohms from the tip of the plug wire to either of the wires coming from the coil. Checked the points and they are not grounded. checked the on/off switch and it is not grounded. I do show continuity between the two wires from the coil. Also tried different sparkplugs. The flywheel magnets appear to be strong.
Still no spark at the plug.
What am I missing
GPH85
ArboristSite Operative
Your points aren't grounded? They should show continuity when they are closed and be open when they are open. If your points test out like this the only thing you have left is your condenser...
