Homelite XP1020 Ignition Problems

[sawnami]

This saw will hit and run a second or two and then die. I've checked out the fuel system and ruled that out by swapping carbs with another known good running saw.

It just seems like the timing is off somehow. It backfires violently sometimes when pulling it over and sucks the rope back into the recoil cover so hard that you can see the handle squeeze about half it's length.:msp_scared: If you can withstand pulling it over and the hit and die repeatedly, it will finally start and run great. the last time that I tried starting it, it pulled the rope back so hard that it locked up the starter clutch.

I've tested the condenser with an analog ohm meter to check scale deflection when charging and discharging it and it seems to check out ok. The points are clean and good and adjusted properly. The spark is extremely strong and blue. I'm going to swap the points, coil, and condenser from the known good saw next.

Thought I'd see if anyone had any suggestions.:msp_unsure:

 

[watsonr]

Have you checked to see if the flywheel key is sheared? Also check the points timing against the position of the magnet and the coil leg, I think there is a mark on the flywheel that should point right at the lower leg of the coil. The timing should be when the lower leg is just at the first magnetic strip on the wheel and the points should be on the highest part of the lobe which starts the charge cycle, when it closes it sends the spark. I may be a little off in the description but look at all these and see if the timing is off.

 

[sawnami]

Thanks for the reply! The key is OK. It seems odd that if you keep trying to start it that it will finally start and run fine. It'll really tear you up until you get it started though.


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[Eccentric]

Try setting the points so that they'e a couple thou more closed at full open. That will make them open later, retarding the timing a schosh. May take some of the bite out of starting.

 

[watsonr]

what is the air gap set at and the point gap? Having the air gap incorrect advances/retards the timing as does the point gap by a couple thou

 

[Eccentric]

what is the air gap set at and the point gap? Having the air gap incorrect advances/retards the timing.

Beat you by a minute Randy!

 

[watsonr]

barely beat me!

 

[sawnami]

what is the air gap set at and the point gap? Having the air gap incorrect advances/retards the timing as does the point gap by a couple thou

The coil legs are not exposed when the rotor is installed since the coil is under the rotor. Is there a method of checking with it in place? The coil has a fixed position other than the small clearance between the bolts and holes in the coil.


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[cbfarmall]

The coil legs are not exposed when the rotor is installed since the coil is under the rotor. Is there a method of checking with it in place? The coil has a fixed position other than the small clearance between the bolts and holes in the coil.


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Nothing you can do about this as fas as air gap goes. The coil will rotate within cast-in bosses. You can sometimes advance the timing this way but the air gap won't be adjustable. As a rule, I set the coil CW for maximum advance.

For what it's worth, I have sometimes found a kicking saw to be the result of a flooding condition. My 1020XP is a mean sucker to start sometimes and my 3100G will cop an attitude even once in a while.

Chris B.

 

[sawnami]

Well, I swapped the coil, condenser, and points from a known good running saw last night. This morning it started on the first pull and ran great!

Now that I look back, I'm suspecting the condenser even though it seemed to check OK. The spark with the original coil, condenser, and points seemed amazingly strong and wide. With the good setup the spark is a fine blue spark. I'm going to go through a process of elimination to pinpoint the culprit when I get some more time.

Thanks for the input guys!