Homelite won’t start

WillyBilly · Dec 5, 2022

Was given an old Homelite Model UT10520 chainsaw that was supposed to be in working condition. Have not been able to get it started. Replaced magneto, the spark plug, the fuel filter and the carburetor, and the fuel and air lines appear to be in very good shape. But it will not hit. I’ve sort of run out of options as to what to look for next. The saw is otherwise is in really good condition. Has a small oil leak, but it is less than 1/4 teaspoon. Would really appreaciate any advice anyone could offer!

Thanks!

MadKaw · Dec 5, 2022

Compression is OK?
Just because you've replaced parts doesn't mean the parts are good. Do you have spark?
The most common cause of no-start on the old Homelites is a bad air-purge bulb.
Second is spark plug. (can be bad even if it looks good)
Third is ignition coil.

WillyBilly · Dec 5, 2022

I replaced the prime bulb. Not sure if I have spark but we tried it with a non resistor plug and got nothing. Will run a test for spark tomorrow. Really appreciate the input!

MadKaw · Dec 5, 2022

Don't take this personally...

but you did put fresh fuel mix in it, right?

WillyBilly · Dec 5, 2022

No offense taken at all! Yep. New fuel added.

Bob Hedgecutter · Dec 5, 2022

Correct air/fuel mix entry to the combustion chamber- spark- compression and timing is all you need to organise in a row of ducks to get the saw running.
First and foremost for me would to be ensure you have good strong spark.

WillyBilly · Dec 7, 2022

Cannot get a spark. Tested 3 plugs. Tried with 2 magnetos/ignition coils. Tested wires from magneto to on/off switch and found zero resistance. I’m at a loss as to why no spark.

WillyBilly · Dec 7, 2022

MadKaw said:
Don't take this personally...
but you did put fresh fuel mix in it, right?

Cannot get a spark. Tested 3 plugs. Tried with 2 magnetos/ignition coils. Tested wires from magneto to on/off switch and found zero resistance. I’m at a loss as to why no spark.

Bob Hedgecutter · Dec 7, 2022

Okay, we are talking newer plastic box store type 10520 arent we?

Is the coil grounded by mounting- is there some form of metal to metal contact to the cylinder from the coil? (small plastic saws are not my thing and I am unfamiliar with how things bolt up on them).
Disconnect the kill switch and take it out of the equation- then test for spark.
Correct air gap between coil and flywheel?
Flywheel magnets filthy dirty or rusty?
Do the magnets on the flywheel hold a large screwdriver easily?

WillyBilly · Dec 13, 2022

OKay. Tried 3 ignition coils, 2 new. 3 spark plugs, 2 new. Still no spark. Did the test with the kill switch disconnected and still no spark. Any possible reasons for no spark? I can’t believe these are all faulty parts. I have to be missing something.

WillyBilly · Dec 13, 2022

MadKaw said:
Compression is OK?
Just because you've replaced parts doesn't mean the parts are good. Do you have spark?
The most common cause of no-start on the old Homelites is a bad air-purge bulb.
Second is spark plug. (can be bad even if it looks good)
Third is ignition coil.

I can’t get a spark. Have replaced with ignition coil twice with new parts. Have replaced the spark plug twice with new parts. Have tried disconnecting the kill switch and no spark. I’m thinking it can’t all be bad new parts. Any idea as to what I can be missing???

Bob Hedgecutter · Dec 13, 2022

So we go back to this.

Correct air gap between coil and flywheel?
Flywheel magnets filthy dirty or rusty?
Do the magnets on the flywheel hold a large screwdriver easily?

Bob Hedgecutter · Dec 13, 2022

If that all checks out- maybe you were given a saw that has been well butchered by previous owners and may even have mismatched parts- or at least a dead flywheel, or a missing wire that completes a circuit.

MadKaw · Dec 13, 2022

Spark plug cable?

Cskyline · Dec 17, 2022

I am looking at same issues with my saw . I have checked all the suggestions as mentioned in your post I am leaning towards a new flywheel so looks like we are in the same boat.

Cskyline · Dec 29, 2022

WillyBilly said:
Cannot get a spark. Tested 3 plugs. Tried with 2 magnetos/ignition coils. Tested wires from magneto to on/off switch and found zero resistance. I’m at a loss as to why no spark.

Should you not have a lot of resistance when checking to kill switch to frame ground with switch in the run position ?

stephenmax · Jan 3, 2023

Cskyline said:
Should you not have a lot of resistance when checking to kill switch to frame ground with switch in the run position ?

Yes, you should have an open circuit (infinite resistance) with the switch in the on position. I think the OP may have misspoken when he said he had zero resistance at the kill switch (maybe he was talking about with the switch turned to off). But then the OP said he disconnected the kill switch to no effect, so that is not the problem.

Homelite won’t start

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