Well, scratch clogged exhaust as cause of engine failure. Dave Stragand has recommended using the scientific method when things get tough. Things passed tough weeks ago. Using the notes he supplied me with, I have stated the problem, the symptoms, or observations and as many hypotheses (reasons for failure) as I could come up with, and the experiments I performed to prove them. Some experiments were enough to rule out certain causes. Some were not. For instance, I still haven't used a pressure gauge to -measure- compression. I've only felt it by hand. I will post the Word file of my procedures to the "files" section of the list under folder "#5335". If you see a test I've missed that I could try, or a hypothesis I haven't thought of please let me know. I only have a few things left to try... Rich