Im having trouble with my 12hp briggs starting.

Hello there guys. i am currently building a mudder/offroad tractor. i used it all of last week with no problems then 2 days ago. it was running amazing still yesterday i did not use it. but then today i went to go out for a ride. it would not start. it cranks good, theres good spark. i cleaned the carb, checkd valves. everything seems to be ok. but i think that the intake is not letting gass go into the intake to fire the engine. but there is a good gas flow. it is new gas aswell. Help needed. thanks

Check the gas line and if theres a fuel filter- check that as well. If theyre old, change em. I had a curious issue with my one dynamark- kept having fuel issues, turns out the port from the gas tank ( where fuel line hooks) was crushed when i used a hose clamp on it- i took the tank off, put a small piece of copper tubing in there and it fixed the issue.


As a fluke- disconnect the magneto kill wire and see if it starts- if it does, the ign switch might be bad ( that happened as well on the same tractor).

Make sure there's no water in the system, that always seems to be a silent killer. And check the flywheel key- is that's broken you'll get your spark but at the wrong time.

good point- forgot about those things - i had a RER with a broken flywheel key - thing was 180 degrees off, would suck in air thru the muffler and exhaust thru the carb .... water in the gas is another annoying issue as well .

UPDATE:
Thanks for everyones help, it was none of those tho, i tryed all of them and none of them worked and everything was ok. so i said **** it and i grabedd the gas tank n filled the carb up to the top n turned it overr. she turned on and stayed running for over 30 mins and i turned it off and on high revs low revs. so i am guessing the day it sat.. all the fuel got outta the system and the choke may not be working properly? but i got it going just by given her a prime thanks for everyones help (Y)

SoaresMudder94 wrote:

UPDATE:
Thanks for everyones help, it was none of those tho, i tryed all of them and none of them worked and everything was ok. so i said **** it and i grabedd the gas tank n filled the carb up to the top n turned it overr. she turned on and stayed running for over 30 mins and i turned it off and on high revs low revs. so i am guessing the day it sat.. all the fuel got outta the system and the choke may not be working properly? but i got it going just by given her a prime thanks for everyones help (Y)

Yeah, some times old briggs don't like the cold, if the choke wasn't working then it never would have started without a prime.