Mystery engine issue i cant solve

S

Squirrel Master

Forum Newbie
Hello everyone!

(Pictures attached)

I'm trying to fix my neighbors mower for him. He just got a used Ariens zero turn with a Briggs motor. Its in great shape but we cant get the motor to run right. Below is the list of new parts we've put on...

- new carb set to factory specs
- fuel pump
- fuel filter
- spark plug
- filter
- oil and filter
- air filter

The mower is near-impossible to start when cold. The choke/throttle has to be all the way OFF and it backfires through the muffler and carb constantly until it warms up all the way. It WILL NOT start with the choke/throttle up even a little bit. If we can even get it started, once it warms up it runs halfway decent but not perfect. We've fiddled with the carb adjustment screw a lot and nothing seems to make it any better, only worse. We're running out of parts to replace and ideas to fix it. Hence, the forum post. Any ideas or suggestions would be greatly appreciated!

Please let me know if you have any questions or need any additional details. Thanks in advance everyone!
 
Wow! Thanks for the speedy reply! Sorry for not including that. The valve cover doesnt seem to have it listed. Theres a spot for it but its blank. Does that serial number help? (See attached)
 
How old is the fuel ? Dump ALL the fuel (tank, lines & carb) that came with the mower. Install new fuel.

Put the old stuff in your car... it doesn't care.
 
The gas is new. I know thats not the issue. I havent messed with the valves yet. I'll give that a go in the next couple days. Any other ideas before i get into adjusting valves?
 
Got the valve cover off and the exhaust valve rocker is VERY loose. Im going to measure and adjust but need to make aure im doing it right. I should adjust the valves when they are conpletely closed correct?
 
Squirrel Master said:
Got the valve cover off and the exhaust valve rocker is VERY loose. Im going to measure and adjust but need to make aure im doing it right. I should adjust the valves when they are conpletely closed correct?
Click to expand...
With the Valves Closed, correct.
I've always set them with One valve completely open, and adjust the one that is closed. so if the Intake is down, adjust the Exhaust.
 
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