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Hank F.
Hank F., Technician
Category: Small Engine
Satisfied Customers: 14440
Experience:  Certified on Onan and Generac generators
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Hi, I have an onan b43e-gao16 in a Lincoln welder.

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Hi, I have an onan b43e-gao16 in a Lincoln welder the motor suddenly starting sputtering and quit. Ive checked the fuel lines and carb. (fresh fuel and filter installed prior).Checked plugs no spark. Gap set at 0.035. Checked coil primary and secondary, they are within limits. but has 8 or 9 volts into and out of it. Checked points, irattic week spark(yellow-ish). Replaced condensor.Still poor spark. Points gap was approx 0.026. found two online manuals, one said set them at 0.021. The other said 0.016. this one said the plug gap should be 0.025. Can you tell me the correct specs for this motor and what the voltage should be in and out of the coil? could this be a circut board gone out. or voltage regulator?

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The plugs should be gapped to .025", not .035". This is probably a lot of the problem.

The points should be gapped to .016"


This will not be a voltage regulator, it only controls output voltage.


There is no circuit board on this engine.

It should get voltage from the start switch ignition circuit.

Voltage should be around 12V, but 9 or 10 is usually all that is needed.


Customer: replied 5 years ago.
Hey Hank, thanks for the specs. set points and plugs as suggested still nothing. Spark at points still seems way to weak. what should I try next, new points, starter solenoid, (looks like old ford type). Could it be the problem? How do i test it? This welder does have a "Idler pc board", along with an auto idle switch, idler solenoid (has power an seems like its working) and oil pressure switch.

The auto idle will have nothing to do with the quality of the spark.

Likewise, the starter solenoid will have nothing to do with the spark, either.


If it has been awhile, it sure would not hurt to change the points.

But at a minimum, give them a good cleaning and a thorough examination.


If you are sure the coil is good, the 3 most likely suspects here are:

Bad points.

Bad plug wires.

Low voltage going to the coil.

Try jumping 12V directly from the battery to the positive terminal of the coil and see if this makes a difference.


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