I was recently given two weedeater mowers, one a 5 hp high wheel model. The other a 3 1/2 hp mower. After priming, both will start briefly and then stop. Both have new plugs and fuel. I do not have a manual for either. And I do not understand the throttle system or lack there of a throttle.so I would appreciate any information you could give me in any way you can tell me how the throttle systems are supposed to work. Thank you very much

I think you are starting to realize why they were given away. Sounds like a fuel issue so dump the gas, drop the carb bowl and clean it. Refill with fresh gas but leave the cap off the tank for the moment.

Hi,
Wholeheartedly agree on cleanig the carbs, except they will be different. The 5 HP will have a bowl carb that is most probably plugged in the jet assy that holds on the bowl. While you are at it, hold it upside down with the bowl off; The float should be parallel with the rest of the body or it needs an inlet needle and seat.
The 3.5 HP will need the carb removed from the tank, the inlet screen cleaned and a new diaphragm.
Peace,
Clarke