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Never seen one like this at shows!

ronny p 148

I have a Koehler model K91EP it’s very hard to start will not start unless I take plug out spray shot of starting fluid in plug hole and pull on it till Blue. Take plug out intermittent spark once it fires can’t ask for better running engine generator runs perfect ant info would be helpful ! HP year ??

ronny p 148

Neither external points and condenser like I said once it starts doesn’t skip a beat !! Just starts harder than hell!

ronny p 148

It’s mag behind flywheel external points like I said very hard to start spark not ther all the time when you remove plug and ground but when it finally starts never skips s bday !

Andrew Mackey

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Check the points gap first. Should be .018". Make sure the points are clean by placing a white paper business card between the points and draw out slightly. Open points and remove card. it should come out clean. Any gray or black residue on the card, and points will have to be cleaned. If your spark plug has been wet with gas, replace it. Gas will make the plug misfire under compression. If that does not work, Try replacing the points and condenser. If then you stll have inconsistant spark, chances are the mag is bad. Does not happen often but:shrug: Make sure all connections are clean and tight. be sure the condenser lead is not near the engine block or points cover:eek:


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Get an ignition spark tester. Just grounding the plug while cranking doesn't always give an accurate picture of what is going on. They are just a few bucks.


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As another thought you might pull plug and check clearance distance between top of piston at TDC and length of plug. Since it sounds like you don't have a manual, is maybe possible someone in past installed a shorter plug. That would maybe explain reluctance to start.

Rich Mc

Check the "E" core magneto gap at flywheel, It should be about 0.008 to 0.010. A wide gap would make slow(starting) rpm spark plug voltage low.


Too much metal swarf stuck or jammed in the gap can cause problems too. The metal surfaces should be clean.



The K91 refers to the ENGINE type, not the genset model.
The engine type for this vintage tells displacement and cylinder quantity. K662 was a 66 cubic inch opposed twin. A K361 was a 36ci single. The K341 was a 34ci single. A K301 is a 30 cubic inch single cylinder. A K241 is a 24 cubic inch single. The K161 was a 16ci single, A K91 is 9 cubic inch, single cylinder.

The K662 was 24hp, K361 was 18hp, k341 was 14hp, K301 was 12hp. The K241 was 10hp. The K161 was 8hp , the K91 was about 4hp.

Contact points are a common source of issues with K-singles. aside from being oil fouled or pitted, the springs and ground connection can be a challenge. On battery-coil ignitions, it's not unusual for the engine to stop with closed points, and thus, have battery current flowing continuously through the points. The way the points are designed, point current (ignition coil primary current) flows through the points, through the breaker arm, then THROUGH THE SPRING, to the base, and block ground.

Running battery current through the spring while the engine is actively RUNNING is not a problem, but leave the points closed, and the spring warms up rapidly, eventually causing the spring to get incredibly soft, hence, flaccid. If the breaker point pressure is too low, they will not operate properly- you get intermittant ignition and weak spark.

Check the condenser, too- they go bad.

The coil is NOT an 'ordinary' coil... it's special- designed not only for high vibration, but substantially long coil-'dwell'. If your engine has an automotive coil, it is probably burned internally from being overheated by same circumstance (key left on) or just because it was not designed to handle the G-forces of the single's vibration.