View Single Post
  #20 (permalink)  
Old 01-19-2019, 11:47 AM
Phx Mike's Avatar
Phx Mike Phx Mike is offline
CC Member
Visit my Photo Gallery

 
Join Date: Apr 2016
Location: Phoenix, AZ
Cobra Make, Engine: Kirkham 427 s/c with Pond block 482 FE built by Craft Performance Engines
Posts: 705
Not Ranked     
Default

I have dealt with this a lot over the years - factors contributing to dieseling or run-on include

- increased compression ratio
- increased idle speed
- low fuel octane
- excessive ignition advance at idle
- carb rich
- hot spots (in particular fouled plugs)

Try lowering your idle to around 750-800 rpm, and advance to around 12 degrees max at idle, and make sure you are running unleaded premium fuel.
Reply With Quote