Who Can Diagnose THIS Total Mystery? Win A Prize?

[RichPA]

Without reading through all the threads again, did you try new plugs? They do strange things sometimes and cleaning and gapping doesnt help.It fixed mine, but mine was not as severe as you are describing. It would be an inexpensive try.(A little less than an engine).

[sgwilson904]

Originally Posted by RichPA

Without reading through all the threads again, did you try new plugs? ...

Checked all plugs in the last couple of weeks. They looked good but we replaced them anyway, just in case. That didn't help, either.

[Gary WA]

Originally Posted by sgwilson904

Checked all plugs in the last couple of weeks. They looked good but we replaced them anyway, just in case. That didn't help, either.

Resolved the same problem with the Service truck!!! The filter in the carb, Zenith was a micro filter totally plugged but could not tell till you blew in it by mouth. Also the stand up filter in the tank if you have one may be a micro filter not good!!! Hard to tell if plugged. Use screen type only! Especially with the ethanol gas. Left original right Micro

[sgwilson904]

Originally Posted by Gary WA

Resolved the same problem with the Service truck!!! The filter in the carb, Zenith was a micro filter totally plugged but could not tell till you blew in it by mouth. Also the stand up filter in the tank if you have one may be a micro filter not good!!! Hard to tell if plugged. Use screen type only! Especially with the ethanol gas. Left original right Micro

Yes, Gary, someone else alerted me to this issue on your other thread. I checked and found my Zenith did NOT have the micro filter and the screen filter SEEMED okay. I replaced it anyway, just because of warning it's hard to tell and it did seem to be a plausible cause of my symptoms. Sadly, and like all the other plausible things I've tried and failed, the new/clean screen filter did not resolve the issue.