warren@ihnss.UUCP (Warren Montgomery) (06/04/84)
(net.auto readers who are not mechanics can type 'n', sorry). My el cheapo Briggs & Stratton powered rotary mower has developed a familiar disease that I don't know how to cure. I have seen the same disease in other 4 cycle mowers over the years and never seen it really cured. Anybody know what to do for it? Here are the symptoms: 1) It's very fussy about starting. It starts best with the throttle just bearly open, and must be a allowed to chug along a while before opening it up. 2) It stalls very easily under load. Apparently, it has no torque with the throttle open at slow speed. This makes it unstable. Opening up the throttle can stall it, but backing off will re-start it if it's still spinning. Likewise, I can sometimes recover from a stall induced by heavy grass by backing out AND reducing the throttle. I have recently tuned it, including replacing and adjusting the points, adjusting the aramature gap, replacing the plug and adjusting the mixture screw to specs. (Though it is less unstable with a richer mixture, even though it idles much rougher and slower with this setting). All of this helped, but not much. I can't find any relevant information in the service manuals for this motor, but it must be a common problem. Any help would be appreciated. -- Warren Montgomery ihnss!warren IH x2494
wookie@alice.UUCP (Keith Bauer White Tiger Racing) (06/06/84)
Sounds like the poor thing is a little worn and probabky needs a valve job. I would first lap in the valves to see if that helps as this is a simple procedure on that engine. If that doesn't help the compression may be down and must be restored with new rings and maybe a bit of a honing job. I assume you have thoroughly checked out the carburetor for dirt/varnish buildup etc. It may also be that the carb is worn out allowing air to leak in around the throttle shaft or perhaps the idle jet is worn allowing to much fuel to flow at lower speeds. The carb certainly could be suspect as you say the mixture is richer at lower speeds. Let us know what you find! Keith Bauer White Tiger Racing
ron@brl-vgr.ARPA (Ron Natalie <ron>) (06/07/84)
Air filter?