i have a tvt691 from 2001 twin carbs, popping back through cyl 1  carb, i have changed and gapped the plugs, changed and gapped the coil, readjusted the valves. all of this has slightly improved the problem but i am still popping back through carb#1 and am low on power. I have also bypassed all of the safety switches. any ideas????

https://www.partstree.com/models/tvt691-600401a-tecumseh-engine/
 
Sounds like a leaking/not sealing intake valve on that side/head.
 
You can do a "leak down test" to verify the intake IS leaking before tearing down.
(Combustion happens in the cylinder, valve not fully sealing, combustion comes back
out of the valve, then out the carberator). 
 
 
 
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Thanks, i will do a leak down test

Plz post back how it goes...
 
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you were correct, i had  a sticking valve, a lot of carbon buildup and carbs need to be cleaned again due to a loss of topend power.
 
Thanks for your help

Your welcome Jeff!
 
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