ThunderMax Hard Starting Issues Corrections User Manual
Causes and remedies for starting issues

Causes and Remedies for Starting Issues
If you are experiencing starting issues such as
Hard Start
or
Engine Kick-
back
, the first thing you should do is make sure you are running the latest
firmware version.
Although there are SEVERAL possible reasons for these problems, we have
had great success in fixing this issue by simply updating firmware to the
most current version. This should ALWAYS be your first step.
Other possible causes:
Low battery voltage
Weak or bad battery; Cabling or Corrosion problems
NOTE:
if your battery is over 2 years old, it is approaching the end of its useful life and may be not
delivering required power during start to the Thunder Max module.
Bad primary compensator
Harley upgraded all production models to the SE compensator in 2011 and up because of failing
compensators.
Engines 2006 and prior had little problem (smaller engines) with a different compensator.
We recommend this upgrade as a "preventative" upgrade if nothing else.
It provides better starting, smoother acceleration and better crankshaft life (We have updated our
entire R&D fleet, very pleased with the results)
This is a very common issue and has been found to cause "kick back" and nasty starting.