View Full Version : 12.5 Briggs won't run
bubbandmargie
Sep 26, 2006, 06:45 PM
I posted a question earlier about a Murray mower wiring problem. Thanks for the info. I found the coil was dead and traced all the wiring. Now I am getting fire and gas, but it will not run - or even sputter. The key isn't sheared, and as far as I can tell the bottom end hasn't been opened, but it acts like the timing is off. If I spray starter fluid in the head, it spits back through the intake. I have taken of the head and checked it. Has 100 lb. compression. I've run out of ideas. Do you have any?
thebriggsdude
Sep 26, 2006, 07:30 PM
Oem or aftermarket coil? Course its getting spark now?
"as far as I can tell it hasn't been opened"... meaning you got this used? 100lb. Comp sounds really good.. but I'd take the head off and make sure (turn the engine through all the cycles) that the valves are operating freely basically and not sticking.
bubbandmargie
Sep 27, 2006, 12:02 PM
Yes I did get it used. The main pully had supposedly broken and was missing, but according to the previous owner was running at that time. I've already pulled the head and checked - even pulled the intake valve to further check. Everything is going completely up and down, opening and closing on time. I had put a coil from an '82 model 11hp Briggs to check it with.
thebriggsdude
Sep 27, 2006, 02:10 PM
Coil off a 82 briggs... was it a magnetron coil? Briggs did switch them all to magentron igntions after 83.
bubbandmargie
Sep 27, 2006, 07:49 PM
I'm not familiar with the difference. The 84' coil had a pin in the bottom of the coil for the kill-switch wire. The '82 originally had points, but I had modified it years ago with a chip that fit between the coil and the plates. On the '82 mower the black wire on it was run to a post on the throttle linkage with a yellow wire from there to the switch. It seemed to be firing well on the 12.5 and looked the same. Are they functionally different?
thebriggsdude
Sep 28, 2006, 04:11 AM
You know I'm not a 100% on that, sure I've converted them but never used a coil built for points on a engine built to use a magnetron coil... You can just cut the wires to the points and put a magnetron coil on the one with points.