Satoh S650G Running Rough

   / Satoh S650G Running Rough #1  

KevinKutolowski

New member
Joined
Jul 12, 2003
Messages
6
My Satoh is running rough, missing, trying to backfire and tries to cut out. I have replaced the points, cap, rotor and plug wires and set the timing. This started about three weeks ago when cutting the grass. It ran fine then it heated up and started to run rough, back fired especially under load. after that it would run fine until It heated up. Now after I replaced all the above it runs rough all the time. Any suggestions? I do have the shop manual.
 
   / Satoh S650G Running Rough
  • Thread Starter
#3  
A little gray at start up, then clears
 
   / Satoh S650G Running Rough #4  
<font color="blue">...It ran fine then it heated up and started to run rough... </font>

Head/head gasket check... /forums/images/graemlins/frown.gif
 
   / Satoh S650G Running Rough #5  
<font color="red">Head/head gasket check </font>

I hate to say it, but I think John may be right. /forums/images/graemlins/frown.gif. How hot did it get when it started acting up? REAL hot? Are you losing any coolant? First thing I would do is with the motor cool, pull off the radator cap. Fire it up, and let it warm up. Do you see any bubbles forming in the coolant? If so looks like you got some tear down to do. If no bubbles, it's time for a compresson check. If you don't have a compression gauge, they are not THAT expencive, or some parts stores may rent them out. If you have low pressure in a cylinder, or most lickly two cylinders next to each other, you have a problem.
 
   / Satoh S650G Running Rough #6  
The poster stated that the exhaust was a little grey at startup, then cleared. I'd go with the head gasket too. However, I'd first do a radiator pressure test with the engine cold. If the head gasket is perforated, it's either getting compression gasses in the radiator or coolant in the oil. I wonder if the crankcase oil is milky?
 
   / Satoh S650G Running Rough
  • Thread Starter
#7  
I just checked the compression is 150+ on all cylinders, the manual lists 145 as the right compression. Also the oil is clean no water in the oil. I really don't think it over heated. I'm talking normal heat up, after about 15 to 20 minutes of running under load (grass cutting 4' bushhog).
 
   / Satoh S650G Running Rough #8  
Being the diesel dummy that I am, and the fact that the only 4 stroke gasoline engines I have are on my lawn tractor and pressure washer, I overlooked an obvious fault for which I apologize.

In your quest for finding the problem you said you replaced the points, wires, plugs, etc. Did you replace the capacitor with the points set and the ignition coil. Sometimes, ignition coils will loose their dielectric strength with heat and will internally short. The same thing applies to the capacitor in the distributor.

Again, I apologize, I should have read the post and assimilated it for what it was.
 
   / Satoh S650G Running Rough #9  
You're right, it sounds like a coil or condenser. Ask for a condenser, if you ask for a capacitor you're going to confuse the parts person. They are the same thing though. Also, make sure the little ground strap that runs between the breaker plate and the distributor body is in good shape and the connections are clean, bright and tight.
 
   / Satoh S650G Running Rough
  • Thread Starter
#10  
The condenser is the one part that NAPA had to order and it did not come in yet. That was my first thought. I haven't checked the coil. Does anyone have a cross number for a coil?
 
 
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