Briggs 5hp Issue

[qtband]

This 5hp Briggs wouldn't idle. It also had a very carbonized plug. I bought a new carb and installed it. It idles and runs well but there are 2 issues.
1. When you rev it up and release the throttle, it dies. It starts right away again, but does the same thing.
2. After I clean the plug and run it for a couple of minutes, the plug is black again.

Any answers?
The carb only has an idle adjustment.

Everyone likes pics, so here's one....

 

[landuse]

Are you running it without the air filter?

 

[Kansaskart]

Wouldn't cost much to start with the easy stuff. See what a new spark plug does. Probably not much lol. Also, is that a brand new carb, or just new to the engine? Before getting carried away might check the compression, or find someone that can. That carb runs off a diaphragm if it's low it won't run right. Knowing if the ole boy is worn out and needing rebuilt will save you a lot of time and frustration. I learned that at age 10 when I had every new external part possible on my 2hp Briggs before someone told me about compression and that I had near zero.

Also, that carb does have another adjustment I see it in the pic. Turn it all the way in, don't tighten just till it stops, then back it out 1 turn. That and a plug would be easy and cheap to try.

 

[Kentucky Boy]

The old Briggs might need the valves cleaned and re-lapped. If the plug gets black that fast I'd say it's running very rich or the rings are shot.

 

[qtband]

Thanks for the ideas. I'm taking it off the kart and putting a new Ironton on it. In the winter, I'll tear it down and rebuild it.