Post by ltdhpp on Aug 9, 2013 11:33:15 GMT -5
Or is it just signal-or-no-signal?
Ive been pulling my hair out over this thing, and have tried/tested everything including a brand new carb.
Whatever is happening, it will re-create the symptoms fine while it runs on the stand, then will magically clear up and run as good as ever, for no apparent reason.
When it acts up, it doesn't want to rev up, and if you try it will stall, then not want to restart for a bit. According to my tach (and a spark test) I have spark as soon as I can crank it after it shuts off - I have no indication of loss of spark, unless it comes back that quick. It acts the same with the blue CDI and the stock one. I put the stock coil wire back on and have all but abused it trying to make it act up, and it doesn't
Then on the other hand (this is well after it's warmed up) it will randomly run and rev up fine after doing/touching nothing. It revs just as good as ever, and sure enough if I shut it down when it is 'good', it will start right back up just fine. Then about the time I think about putting it back together to go for a ride - it won't rev up anymore, after doing nothing.
Its got fresh gas that's been running fine in my mower - no vacuum leaks - valves are spot on - compression pumps up to almost 200psi. There is plenty of fuel flowing into the carb.
So, if I have spark, fuel, and compression, all that leaves is timing, right?
It behaves exactly the same with the new carb as the old one. I was able the get the a/f screw and idle set while it was 'good'
It sort of makes sense in my head... ignition needs to advance when it revs up, right? So if it doesn't, or if timing is way off, the fuel wont burn, loading it up and making it extra rich? maybe making it flood out? When it is 'bad' and shuts off, it does act like a carb thats flooded, it takes a little time and nursing the throttle to start it back up.
I have a replacement trigger on the way, but I'm not looking forward to replacing it, since one of my fan bolts has a head rounded off....
Ive been pulling my hair out over this thing, and have tried/tested everything including a brand new carb.
Whatever is happening, it will re-create the symptoms fine while it runs on the stand, then will magically clear up and run as good as ever, for no apparent reason.
When it acts up, it doesn't want to rev up, and if you try it will stall, then not want to restart for a bit. According to my tach (and a spark test) I have spark as soon as I can crank it after it shuts off - I have no indication of loss of spark, unless it comes back that quick. It acts the same with the blue CDI and the stock one. I put the stock coil wire back on and have all but abused it trying to make it act up, and it doesn't
Then on the other hand (this is well after it's warmed up) it will randomly run and rev up fine after doing/touching nothing. It revs just as good as ever, and sure enough if I shut it down when it is 'good', it will start right back up just fine. Then about the time I think about putting it back together to go for a ride - it won't rev up anymore, after doing nothing.
Its got fresh gas that's been running fine in my mower - no vacuum leaks - valves are spot on - compression pumps up to almost 200psi. There is plenty of fuel flowing into the carb.
So, if I have spark, fuel, and compression, all that leaves is timing, right?
It behaves exactly the same with the new carb as the old one. I was able the get the a/f screw and idle set while it was 'good'
It sort of makes sense in my head... ignition needs to advance when it revs up, right? So if it doesn't, or if timing is way off, the fuel wont burn, loading it up and making it extra rich? maybe making it flood out? When it is 'bad' and shuts off, it does act like a carb thats flooded, it takes a little time and nursing the throttle to start it back up.
I have a replacement trigger on the way, but I'm not looking forward to replacing it, since one of my fan bolts has a head rounded off....
jet
