Carbon Buildup on my ZDZ 80
 

Mike:

A little while back I emailed you about the carbon buildup on my ZDZ 80. I think you said that some carbon was normal but that it shouldn't be building up around the exhaust port. Anyways here is a picture of my engine with the muffler removed. Note the buildup around the exhaust port. The piston has a light buildup. The top of the piston has considerable build up. The cylinder wall is clean. The engine has always been run on Mobil MX1 2T (30:1 for break in and 40:1 since). I'm surprised at the amount of buildup given that I only have about 10 gallons through this engine. The engine runs great, starts easy, idles well and has lots of power. I'd like to keep it that way. Please let me know what you think. Is this a normal buildup? If not does it indicate a hot running engine? Your help is most appreciated.


sschwell

RE: Carbon Buildup on my ZDZ 80
 

What you are showing me could be a hot running engine, and it appears your muffler is loose with alot of leakage?? Be sure the carb has a cool air supply(no ram air!) and the exit air opening uses a spoiler. Typical CHT should range from 190-220F.
Keep me posted.

RE: Carbon Buildup on my ZDZ 80
 

Thanks Mike- much appreciated.