boovuc 1,090 #1 Posted June 26, 2012 Hey guys, I have an old 4HP manual push LawnBoy mower that starts right up but will quit within 2 to 5 minutes of use. (Shuts down as though you let go of the safety bar with a few hard spits and sputters). If you let it sit until it cools, it will fire right back up only to shutdown again. I have tried a new fuel mix, changed plugs, tore the carb off and cleaned it though it was very clean and checked the gas cap and the tank screen. This is a solid state ignition on this model. (S19ZPM 4 HP 2-cycle). (Model 680542). I've owned this for 15+ years and I love it but as my only push/trim mower, I can't use it. Any ideas? Thanks, Share this post Link to post Share on other sites
bowtiebutler956 649 #2 Posted June 26, 2012 Sounds like a bad coil to me. I always liked the old aluminum deck, 2 stroke Lawn Boys. They were a great machine, nothing like the Tecky powered, thin, flimsy steel deck ones they sell at Home Depot these days. Matt :flags-texas: Share this post Link to post Share on other sites
dodge78 90 #3 Posted June 26, 2012 I say coil also. Easy test, mow until it dies then check for spark. No spark, its the coil. Share this post Link to post Share on other sites
boovuc 1,090 #4 Posted June 27, 2012 I need to get a book for this puppy. You'd think after almost 2 decades that I would have looked for one but it really has never ever left me sit. God I love these old Lawn boys! If anyone has a manual or blowup of this model, let me know. Thanks, Guys! Share this post Link to post Share on other sites
gwgdog66 23 #5 Posted June 27, 2012 I need to get a book for this puppy. You'd think after almost 2 decades that I would have looked for one but it really has never ever left me sit. God I love these old Lawn boys! If anyone has a manual or blowup of this model, let me know. Thanks, Guys! Have you cleaned out the exhaust ports lately? I seem to remember they would clog up sometimes, gradual power loss then die. The Solid state ignition would also go out on them, be running fine then just quit. I really like the old OMC engines they used to put on them. Share this post Link to post Share on other sites
dodge78 90 #6 Posted June 28, 2012 https://support.lawn...nualsResultPage Hit the search button. There is an online manual, parts lookup and specs. Share this post Link to post Share on other sites
boovuc 1,090 #7 Posted June 30, 2012 Thanks, Dodge! Good info on this mower on the online manual. I also found it on another sight after digging a bit! I may be all wet but for those suggesting a coil, this is an electronic ignition and it doesn't have a coil to the best of my knowledge. If there is something I'm missing, please pipe in. I was suprised to learn that this model was made in the early 90's. I thought it was older. I guess I got a real good deal on it since it was only about 4 years old when I got my hands on it. I paid about 60 bucks for it then. I did manage to get it to run while I cut grass at camp without it shutting down. (It was a cool day on Tuesday though). I threw out the new Champion plug, (CJ14), and replaced with a new autolite, I cut a new foam air filter and I mixed brand new 50 to 1 high test with stihl 2 stroke oil. I did take the muffler off and cleaned the carbon per what the manual stated. It was not plugged up though. We'll see what it does in this humidity and heat on Sunday. Thanks, Share this post Link to post Share on other sites
bowtiebutler956 649 #8 Posted June 30, 2012 Electronic ignitions still have coils. Sometimes they are built together as one unit, but they always have a coil. Matt :flags-texas: Share this post Link to post Share on other sites