Older Homelite XL2 (mag case) is sort of a family heirloom and would like to get it going. It ran in the past, but the spark plug wire was bad so I put on a new electronic one and ditched the points and condenser. Couldn't make it fire no matter what I did. I had an old XL and put that carb on, nothing. New plug, new fuel lines, hot spark on the plug, nothing. I just swapped the reed valve using the old one and got it to fire. (Also 125# compression) It will fire and idle for about 3-4 seconds. I see s tiny gap on the reed valve--it's stainless and is riveted to the block so I can't turn it over. Should it be completely closed? Changing out the reed has yielded the most promising result, so that tells me that the pulse was not drawing fuel into the cylinder. I will go back with the carb that came on it and see if it runs--it has been cleaned within an inch of its life. Any insights would be greatly appreciated.
Homelite XL2 nagging problem
- Thread starter purdyite
- Start date
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At 125psi, if your compression tester is for small engines, it’s on the cusp of running. It may run it may not. Ideally you want 150psi.
Regarding the reeds ideally they should seal, but in practise I have round if they have just a tiny gap, they’ll still run, you may just get a soaked air filter and be down on power / performance. The tune may sound off too.
From what I've read it seems your problem may be with your new ignition module. Is it possible it's a different brand than the flywheel? Some of these unmatched ignitions work and some don't. Did you check it for spark and timing? Sounds like your compression is plenty and I wouldn't be too concerned about the reed valve unless it's bent or badly warped.
OnlyHomelites
ArboristSite Member
Spot on! The flywheel key location is different on the points coil flywheel vs the electronic ignition flywheel. Due to the points box being cast into the crankcase assembly, the only way to use a late electronic coil flywheel on the early crankcase is to use a cut-off wheel to remove it.
I can put fuel down the throat of the carb and get it to run and it sounds like it's firing normally, which leads me to the carb or the reed valve. After it burns the fuel in the throat, it dies. And, with a different reed valve it tries to run, so I feel like it's unlikely to be the coil...but this is the first points saw I have used a new coil on. So...how do I check the spark timing? I'm open to all suggestions, I know the danger of saying "it must be the ________".
Have you replaced the diaphragms in the carb? That should be one of your first steps with an old saw, they get stiff and stop doing their job. Stiff carb diaphragms will not pump or meter the fuel correctly and absolutely can cause it to start on choke, run for a few moments and then stall.
What’s the condition of the diaphanous ? Sounds like it’s stiff and not letting fuel in if you have to feed it
This sounds exactly like bad carb diaphragms, it's not pumping fuel.
I thought all I had to do was replace the coil--didn't know that the flywheel is also involved, so the original flywheel is on the saw.
Before replacing the reed valve, I would pull the rope repeatedly with no response. Then, when I took the carb off, the chambers would be full of fuel, but the spark plug would be dry. No gas coming out the exhaust; no evidence of flooding, just no response. So far the only change is after changing the reed valve. It's not bent or warped, only a gap of maybe a half a millimeter.
Now that I think about it, I guess the reed valve must be working or it wouldn't have fuel to and through the carb, right?
The diaphragms seem pliable; I can swap those out and see if that makes a difference.
If the reeds aren’t sealing, crankcase pressure goes back through the carb.
Carbs work on vacuum
Then I'd say the evidence suggests that the reed valve is working. Now I suspect the diaphragm...
You'll want to replace both the metering diaphragm and the fuel pump diaphragm. Perhaps also the inlet needle while you're in the carb, and also check the metering lever height.
Go back and read post #4.
You cannot just swap in the electronic module into the points homies. You will get a spark but it's not correct. At least 3 different ignition systems and mixing ignition parts WILL NOT get a run even though you have spark. (I've tried such)
Sometimes you can swap in a Atom chip in place of points condenser but i only do such as a test of the points/condenser and if I get a run I install new points condenser. I keep couple of atom chips around just for such testing. I do not trust the Nova chips for long term reliability and some don't work when new. (Only buy them if they have a warranty.
If you want to keep the saw get a set of NEW points, condenser and points coil. (or find a points type donor saw)
You cannot just swap in electronic modules in the homies.
125 lbs is A ok when all else is correct. I've seen them little Homies run, cut, and start good with 80 lbs compression.
You say the magneto had a bad plug wire. Some of them plug wires unscrew from the mag tower for replacement.
Lots of on-line info about Homiie XL2 ignitions. Here is one example
https://video.search.yahoo.com/sear...c8307ba7683ca9872203e1da465c5d0b&action=click
You cannot just swap in the electronic module into the points homies. You will get a spark but it's not correct. At least 3 different ignition systems and mixing ignition parts WILL NOT get a run even though you have spark. (I've tried such)
Sometimes you can swap in a Atom chip in place of points condenser but i only do such as a test of the points/condenser and if I get a run I install new points condenser. I keep couple of atom chips around just for such testing. I do not trust the Nova chips for long term reliability and some don't work when new. (Only buy them if they have a warranty.
If you want to keep the saw get a set of NEW points, condenser and points coil. (or find a points type donor saw)
You cannot just swap in electronic modules in the homies.
125 lbs is A ok when all else is correct. I've seen them little Homies run, cut, and start good with 80 lbs compression.
You say the magneto had a bad plug wire. Some of them plug wires unscrew from the mag tower for replacement.
Lots of on-line info about Homiie XL2 ignitions. Here is one example
https://video.search.yahoo.com/sear...c8307ba7683ca9872203e1da465c5d0b&action=click
You say it runs, does it rev up and die or just a steady slow speed?
With the choke on, it will fire, run for maybe 2-3 seconds, then die, so I didn't hit the throttle before it died.
It will do this now, with a different reed valve. I don't have to pour gas in the carb to get it to do that, but it won't stay running.
What I’m getting at is as it runs on the little fuel it will lean out and rev up then die. If it doesn’t rev up just chugs along at low speed then your coil won’t work even though you have spark the timing is off. If it does then your fighting the carb and possibly the crank seals. If a saw sit for a long time sometimes those reed valve will stick shut as well
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