Nissan NS5B gas cap

[ajcampbell31]

Question - 2003 Nissan 5hp NS5B - does the gas cap on the tank keep a vacuum? It seems that when I take the cap off, he engine seems to start to sputter and eventually dies. My tank cap threads are virtually non existant so I have to keep a bungee cord on the cap. But when I had to add fuel, I had to take the cap off, the engine bogged down in neutral and then quit. It did this both times. The first time i chalked up to coincidence, but twice seems to erase that thoery.

 

[Sea Rider]

If upper cap vent screw is open letting air in, working without cap or with screwed threads while in operation, should have 0 bogging down issues.. That's a 13 year oldie, clean all fuel related parts, remove tank, internal fuel mesh filter, large filter and carb as well. Install a new plug tip gapped to 1.0 mm tight, use fresh fuel...

Happy Boating

 

[pvanv]

No, no vacuum, unless the vent is shut.