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K91 Engine Engine

The K91 is an engine. It powers generator sets from Kohler, including the ES799.

Also known as: K91

Engine specifications

Generator sets powered by this engine

1

Common problems

15
  • Starter not engaging
    Fix: Drive pinion may be spinning. Automotive crank plants only
  • S1 to terminal t3 on regulator open.
    Fix: *Correct connections.
  • No outflow (no exciter voltage-into AC volts)
    Cause: Regulator relay RR could be causing overcharged or undercharged battery--check this after resistor check
    Fix: Check contacts of relay CC may not be closing to complete battery charging circuit. Check brushes, AC leads, and AC armature for open circuits
  • No build-up.
    Cause: L Open circuit between battery and field. l Battery discharged.
    Fix: *Make correct connections. *l Charge battery.
  • Load relay L dirty or open contacts
    Fix: Check for dirty or open contacts--replace relay if needed
  • Insufficient load
    Fix: A load of 60 watts or more is needed to start automatic plant. A remote switch can be added to test run these plants--check diagrams
  • Generator output erratic.
    Cause: L Regulator sensing terminals not connected properly.
    Fix: *Check terminals 5 and 6 (120 V. connection) or terminals 5 and 7 (240 V. connection). *l Correct connections.
  • Generator faulty on plants with automotive cranking
    Fix: Check for faulty DC generator--excessive resistance in R2 resistor. If overcharging occurs, R2 resistance may be too little
  • Dirty commutator.
    Fix: *Clean commutator.
  • Cranking reset trips during cranking
    Fix: Reset the reset button--if plant still does not crank, check for open circuit
  • Cranking contactor C contacts do not close when switch is moved to on position
    Fix: Replace relay C
  • Choke heater circuit failure
    Cause: The choke valve could ‘stick’ the air cleaner
    Fix: Check the Ohm value of the resistor with a Volt-Ohmmeter. If faulty and allows higher voltage, it could cause the choke for starting
  • Check field circuit for open shunt
    Cause: Open field resistor connection
  • Center tap missing on three wire automatic plants
    Fix: Check for loose leads or missing center tap
  • Battery not being charged properly
    Cause: Check condition of battery--may be sulfated or have cracked cell. Replace as needed
    Fix: Check charge switch if left in HAND CRANK position, battery will not be charged

Compiled from service & troubleshooting documentation across every generator set that uses the K91.

Common questions

Which generators use the K91 engine?

The K91 powers 1 generator set(s), including Kohler ES799.

What is a common problem with the K91 engine?

A commonly reported issue on generators using the K91 is: Starter not engaging. Fix: Drive pinion may be spinning. Automotive crank plants only.