Need help with motor issues

[Mat Perucci]

So I put the new coil in, checked my connections every wire is in good shape all the connections are good. But, still not producing great spark. I have the b212 and b112 both have identical engines and the b112 has a spark about 5 times hotter. On the b212 I have the electronic igniton. I got it to run. Then ran it with my 46'' blade. Has good power but about 15 minutes after it gets running it starts bogging down and runs like garbage and the longer it goes the worse it gets until it shuts off. I know that the carbuator is good and clean and it has a full tank of gas. Let it cool off for an hour.. tried to start it again and it would fire a couple times but I ended up pushing it back to the garage. Does anybody have a clue whats up with this motor??

[Scott Salmons]

Is the electronic ignition the Magnatron conversion or the Nova module that replaces the points. If its a module I wonder if the heat is to much? I sympathize with you on the problem, I have been going through the wringer with my B-112. I have replaced all of the ignition.

[Bunky]

Mat did you check the spark when it quit?? if there was spark I wonder if you don't have a Valve too tight or sticking, I have seen this same description on mowers before and they would run good for a few minutes, then as the heated up it would take the clearance out of the valve and Tappet and hold the valve open making it loose compression and eventually quiting, then after it cooled it was good for a few more minutes.. just a thought.. If you had spark then I would try a Battery ignition on it just to test it..

[Mat Perucci]

That sounds like a good idea to check the valves or maybe replace them.

[MrSteele]

Replacing the valves will do no good, either, if the valve lash is not set when that is done. A valve becomes 'too long' with wear, and does not seat properly, making many pull their hair out, or throw the engine away. I have received many junk engines that wouldn't run when hot. Simply remove the head and valve cover, remove the intake valve and grind the stem to about .020 clearance and reassemble. While you have it down that far, I'd go ahead and check the exhaust, as well. Valves without enough clearance tend to grow as they heat up, closing the gap between the tappet and the stem. Let them cool a bit, and the engine runs again. I'd check the valves if I were you.

[Tasbrus]

Yup, I've also bought a tractor with a newly rebuilt motor that would only run when cold. Checked the valve clearance and it had none. Ground the valve stems to proper clearance and it was fine.