Model: 100202 0180
Type: 01
Serial: 6606141
Off a 1965-ish Simplicity S4 snowblower - A golden machine by the way.
The engine starts fine, runs at idle very well. Rev it up and it spits and quits immediately. A gradual increase in RPM also yields the same. I have tried several different Pulsa Jet carbs (I have many), still the same result.
It is as though timing changes at rev-up-?. The key is good. The starter clutch is tight-in. The points are at exactly 0.02 as the book mentions. What could be going on here? Starving of fuel upon more demand? No high-speed adjustment on this carb, only idle pin on the side.
At 56 years old don’t you also start to spit, sputter and cough when some one wants you moving at full speed? Now with that out of the way I have a few questions and suggestions. Questions first; have you tried changing the points and condenser? Have you replaced the diaphragm on the carb? Have you checked that the auxiliary tank has not been damaged? Here’s why I ask these questions. Pitted points or an old condenser can contribute to this problem, especially the condenser, which will allow arcing at the points. You can try setting the point gap at .018”, which I’ve found does help as engines get old. A diaphragm which has been sitting around will not pump properly and cause this problem. The auxiliary tank is the small area inside the main tank which acts like a float bowl. I’ve see these damaged, where they can no longer keep the proper amount of fuel in them.
#3
skippymud
Hey Rivets,
Thanks for the cool introduction and your speedy return!
I have replaced and/or made the following changes this week:
New Points and Condenser set to 0.02 initially per spec, now at 0.018 per your recommendation
New Diaphragm
New Low-speed (idle) pin assembly
New CJ8 Spark Plug and pre-set to 0.03
Carb cleaned 100%, all holes and ports, etc.
Reset the Magneto to 0.012 per 2-leg 0.01-0.14 spec
The strange thing that I noticed just tonight is that it will run at top RPM fine and strong with the idle mixture screw at a bit lean (SCR in). But that setting is too lean to run at idle. Any ideas? Bad gas? The gas is treated and about 4-5 months old. All of my other machines run fine on this gas.
Ken
#4
skippymud
Hey Rivets,
So I set the idle screw where it works for high-speed and turned the idle RPM screw to where it will run well. I think it's good!
