Outer Limits 4x4 Board

My old farm ute is getting hard to start. I think the spark side of things is pretty good but I'm not very good with carbies and so am not sure what I can do in terms of testing or maintenance in that area. A bit of fuel straight down the carby usually gets the ute going, but I would rather fix the problem if possible. Any advice would be greatly appreciated. Thanks for reading.

Muz