I have a 24 hp briggs & stratton els 725 motor that started backfiring yesterday. i checked the valves'cleaned the carburator,changed the air filter,changed the fuel filter. the backfiring occurs...
The engine ignition can be interupted by a safety switch (seat) out of place or adjustment, or a carburetor fuel solenoid that is loosing it's supply of voltage.
1) Check the wiring at the starter area, looking for a main engine wiring harness plug-in.
Check for connections that are burnt or loose.
2) If you can locate the 'kill' wire connection at the main harness, disconnect it, and retry the engine.
3) If the engine continues to fail to run properly: you might replace the plugs first, then I have listed a few things to check. They may not all aply, but this may help with an idea or two to try.
1) Determine that there is spark?
2) Have you used a type of spark tester?
3) What is the condition of the plug. Brown or dark brown is OK. Black or silver is NOT Ok.
*If you do not have a spark tester,
a) remove the plug, and with it connected to the wire,
b) find a portion of metal around the cylinder that you can ground it on, and then pull the rope.
c) If the plug is black, you may see spark, but you should replace the plug.
*** PLEASE NOTE ; if there is excess fuel in the cylinder or on spark plug,
it can catch fire, so be carefull to cover the hole with a heavy rag so that any fuel
cannot be exposed to spark plug durning test !!!!
Get back with me on how this issue works out.
Fuel Related issues that take a certain amount of time to appear
Depending on make and model of mowers:
a) Fuel tank outlet plugged (some have a screen filter,
some are 90' angle and plug with rust and debris inside the corner of fitting)
b) Fuel lines collapse when they are routed thru fasteners and between frame and seat decks
c) Fuel cap vent clogged
d) Fuel filter clogged
e) any fitting that has an orifice that can trap debris or rust will eventually become clogged
f) fitting on the side of the carburetor
g) some systems have a filter inside the line at the opening of the carb inlet
h) fuel pump
i) vacuum hoses to fuel pump
j) debris under inlet needle/seat on carb
Fuel Starvation - Float Bowl Carburetor
1) remove air filter assembly
*be cautious of tearing the mounting gasket. If it does tear, you HAVE to replace it. It is part of the priming system
2) remove the float bowl fastener. This is the main jet
3) carefully remove the float bowl, the rubber o-ring/gasket will not be able to be used if it is removed, you WILL have to replace it
4) using a spray 'carb cleaner'
spray up thru the center of the carburetor
spray and clean the main jet with cleaner and 'tag' wire
(tag wire is very thin, and can be used to clean the hole in the center of the main jet)
5) clean any debris from inside the bowl or carb body
6) re-install bowl and center bolt, air filter assembly
*if you need gaskets, your Briggs dealer can supply. The kit is cheaper than individual gaskets, and all the parts needed to finish the above repair are in the kit.
Nov 22, 2009 |
Craftsman 24 Hp 48" Deck Yard Tractor