Ed Kennell 41,403 #1 Posted September 5, 2014 This Briggs is in the MTD 700 I just adopted. If this post should not be here, please feel free to move it to non WH forum. I just thought I would get more help here. I put in a new battery and she cranks over real well...no starter/ solenoid problem, but no spark at the plug. Cleaned the flywheel and pick up and re installed w/ 0.010" gap...still no spark. Did some resistance checks. Open here Dead short here, also have dead short from flywheel to the wire coming from behind the flywheel that attaches to this lug. Help please......Thanks Share this post Link to post Share on other sites
tbarnhart 240 #2 Posted September 6, 2014 (edited) If that is a single cyl Magnetron ignition, all you should need is good magnets going past the poles and the small spade connector unhooked. If it still doesn't spark, get a new ignition. I forgot to ask, does that engine have points? If it does, what I said above does not apply. If it's a points engine, I would find a good magnetron off of a newer Briggs and simplify the whole system. The Briggs Magnetron was one of the best small engine ignitions for a long time. Edited September 6, 2014 by tbarnhart Share this post Link to post Share on other sites
Ed Kennell 41,403 #3 Posted September 6, 2014 It is a single cyl. How do I tell if it is a Magnetron ? The magnet on the flywheel feels real strong. Are you saying the wire coming from behind the flywheel should not be connected to the small lug where I have the black probe in the second picture ? Is 0.010" the correct gap ? How do I know if it has points ? Are they behind the flywheel ? Sorry I don't know much about the Briggs...I could not find a plate to get any info from. All I know is it's a 7HP in a 1969 MTD lawn tractor. 1 Share this post Link to post Share on other sites
Ed Kennell 41,403 #4 Posted September 6, 2014 C'mon gotta be some Briggs Gurus out there. Don't shun this Li'l green tractor. Share this post Link to post Share on other sites
tbarnhart 240 #5 Posted September 6, 2014 If that thing has a wire going under the flywheel and its the original 69 engine, then, yes it has points under the flywheel. I don't know that much about the briggs points system. Briggs had changed over to the solid state Magnetron ignition about the time I came along in small engine repair. The magneto unit is probably not bad, but I'm not sure how to test it. I'd would go looking under the flywheel at the points or consider getting rid of them and going with a solid state option. There are several different point replacement modules that can be installed (Atom, Nova, etc.) as well as a kit from Briggs that added the Magnetron trigger to your existing module. I remember installing a few of them back in the day. I don't know if they are still available from Briggs. I would just take the ignition that you got and go to your mower repair Briggs scrapyard and find an ignition from a newer engine that has the solid state Magnetron. If the mounting holes line up, the general curvature at the flywheel is close, and the lead is long enough to reach the plug, it should work. The Magnetron ignitions only have one small wire for a kill wire-ground it and it kills spark. Share this post Link to post Share on other sites
gwest_ca-(File Mod) 11,393 #6 Posted September 6, 2014 Here is an old sheet on the early conversions. I think the later coils that included this module look completely different in that it is concealed under the coating. There are 2 pages so download the file. Garry Adding - I think the flywheel can have only one magnet for this to work but not sure. Share this post Link to post Share on other sites
Ed Kennell 41,403 #7 Posted September 6, 2014 OK, both for the info. I just finished pulling the flywheel and this is what I found. The shaft / flywheel key was sheared so flywheel could have been in the wrong position. The points do not appear to open with shaft rotation. I can't see the lifter moving at all. Will check it later. Had to quit to watch Penn State game. TBC Share this post Link to post Share on other sites
Ed Kennell 41,403 #8 Posted September 6, 2014 (edited) Well, Comcast Cable lost all local Tv which carries the Penn State games, so I went back to the Briggs. The points plunger was working, I just did not turn the crank thru two revs. The points looked like they were just newly installed but they did not contact square. A little fine tuning by bending the bracket lined up the contacts. Set the points to 0.019" and mag to 0.010" gaps. Made a new key , and reassembled. Gave her a squirt of Starter fluid cranked her about 10 revs. and got the sweet sound of success. She's ALIVE. MVI_3428.MOV Edited September 6, 2014 by ekennell 1 Share this post Link to post Share on other sites
tbarnhart 240 #9 Posted September 7, 2014 good work Share this post Link to post Share on other sites
