So how do these new style Techumseh gas caps actually work?

[legbuh]

I am helping a neighbor with his blower. I did a fuel vent test and it really slows to a trickle when the cap is tightened. I believe that is part of the problem with his blower. The cap is the newer Techumseh style like this:

Do these go bad? And how do they actually work? I don't see a hole or vent anywhere in the cap. Is it witchcraft? haha. Thanks!

 

[RandyT]

They work by venting through the thread spiral. If overtightened it will restrict the venting to the point that will stop of flow of fuel from the tank. That cap is supposed to be started on the threads, and then with a quick flick spin the cap down onto the threads and then don't touch it.

Was a Tecumseh dealer for years . A guess actually still considered a dealer for parts and service

 

[legbuh]

Makes sense. Thanks! Don't crank er down!

 

[RandyT]

Correct. Have seen this issue from various customers over the years. People want to tighten the caps down like you would any other mower fuel cap, but on the Tecumseh engines will basically cause an interference fit and stop tank venting.