Have an old xl12 saw. It had been setting up for some time I cleaned her up, rebuilt the carb and got her running. Problem, she runs for about 1-2 minutes then shuts off just like you hit the kill switch. Then she want crank again, till I pull and pull and pull. I've checked the kill switch (removed the kill wire), checked the fire, removed the flywheel checked the key, everything looks good. Plan on doing a leak test later on. Was wondering if the coil is going out but I check the fire as soon as it shuts off and it looks good. Any advise would be appreciated.
XL12 want stay running
- Thread starter ARayT
- Start date
EggShooterist
Member
Plugged tank vent?
Plugged vent- plugged filter or collapsing fuel line are possible.
Sometimes with age and funny fuels we don't get here- a fuel line will become soft and mushy, under vacuum it will suck flat and cut off the fuel supply.
If I was being completely honest though, I do not know a whole lot about old Homelites and if it has a coil- it could well be heating up and breaking the circuit- connecting again when cooled- but I would expect that to happen say 10 minutes or so in and progressively get worse.
Sometimes with age and funny fuels we don't get here- a fuel line will become soft and mushy, under vacuum it will suck flat and cut off the fuel supply.
If I was being completely honest though, I do not know a whole lot about old Homelites and if it has a coil- it could well be heating up and breaking the circuit- connecting again when cooled- but I would expect that to happen say 10 minutes or so in and progressively get worse.
Well, that all depends on the gauge you are using and how it reads on small engines.
If it is a standard automotive gauge it will not give a true reading- but if you have another known to run good saw and you test it to get the same kind of reading, odds are compression is okay.
With a proper small engine tester- minimum 120psi Id say for a two stroke to run- more ideal is 140-180 range, but have had some that still ran at around 100 psi.
EggShooterist
Member
Sure thing bud. If it's like some of the old Homelite saws I've messed with, it might be in the cap. Duck bill valve that can turn to goo. It was under a porous brass plug in those saws.
EggShooterist
Member
Like Mr. hedgecutter stated, thats pretty low if its s proper small engine compression gauge. It makes a big difference. As an example, on a saw I have, it tested a bit over 200 psi with an Echo small engine gauge but couldn't hit 90 with an automotive unit.
Thanks, The duckbill valve is in good shape. I was checking it w an auto gauge, never knew there was a difference. What's the difference, how can an input to a gauge w a sealed line know the difference? I'm not doughting what your saying just seems strange. Thanks Again for the advice.. I'll look into getting a different gauge.
Appreciate the help. Ray
Appreciate the help. Ray
Basically the differences lay in the volume of vapour available to the gauge per engine revolution and the pressure it is delivered at- the length of the tube from combustion chamber to gauge and the position/type of valve allowing the vapours to pass- and the springs and balances of the gauge itself.
EggShooterist
Member
Correct. Schrader valves are in the threaded ends of the small engine guages. Or should be anyway. My Echo guage also has a 10mm adapter for the small plug holes. It also has the Schrader valve in it.