Hey All. I'm new to the forum so please excuse me if I mess up on any posting rules...
I have a Husqvarna YTH24v48 with a Briggs & Stratton Intek V-Twin engine model 44N877-0003-G1 170815YG. I've been living with a persistent afterfire from the exhaust port on cyclinder 2 since August 2019. The lawnmower was purchased with a damaged steering assembly from a thrift store with almost no hours (9-11) on it. The engine seems to run strong under load but I can't seem to find the cause of the afterfire.
The issue seems to be almost identical to the following post on this forum and youtube video:
www.lawnmowerforum.com
When the engine runs on only one cylinder the afterfire goes away and it doesn't matter which cylinder. When both spark plugs are connected the afterfire returns only to cylinder 2. I have comfirmed the afterfire with the muffler off. The only difference between cylinder 1 and 2 is that cylinder 2 has higher compression by about 8%.
I have been through a bunch of engine tests, which I'll list at the end, but I haven't been able to see anything but a healthy new engine. I finally took the carburetor off for inspection based on the forum post above having the wrong carburetor. The only thing I found was slightly damaged float bowl gasket (698781) on a round section that did not seal anything. I replaced the gasket just in case, but it still continues to afterfire. The carburetor was very clean and nothing else seemed to be restricted or damage. I cleaned the carb anyway but nothing has changed. I plan on inspecting the fuel delivery, but I'm pretty much stuck except for invasive exploratory disassembly of the engine (cylinder head, camshaft.)
I would appreciate any help with this issue because I'm losing sleep over this. The only thing that stops the popping
and afterfire is running on one cylinder. Thanks in advance.
[Engine Tests Performed]
static compression test
dynamic (running) compression test
leak down test
cylinder contribution test with tachometer
ignition spark tester check
ignition diode check
ignition armature corrosion cleaning
ignition armature gap check
spark plug condition and gap check
ignition wire leak check
swap ignition coils
smoke test intake
smoke test exhaust cylinder 2
visual inspect exhaust valve chamber cyl 2
PB Blaster LMT Cylinder 2
Sta-Bil Fix It
Seafoam in Gas
PB LMT through Intake
Valve lash adjusment .005 Int/Exh
Valve guide check
Bent Push Rod inspection
Valve movement check with both covers remove
Flywheel sheer key inspection
New spark plugs, air filter, fuel filter
Clean emulsion tube with wire and carb cleaner
Clean main jet with wire
Blew transfer tube with compressed air
Cleaned air inlets of carb with wire and carb cleaner
Blew carb air inlets with compressed air
Checked backfire solenoid
Inspected float bowl needle
Clean idle circuit with wire and carb cleaner
I have a Husqvarna YTH24v48 with a Briggs & Stratton Intek V-Twin engine model 44N877-0003-G1 170815YG. I've been living with a persistent afterfire from the exhaust port on cyclinder 2 since August 2019. The lawnmower was purchased with a damaged steering assembly from a thrift store with almost no hours (9-11) on it. The engine seems to run strong under load but I can't seem to find the cause of the afterfire.
The issue seems to be almost identical to the following post on this forum and youtube video:
Briggs v-twin backfiring
I have a JD LA135 22HP BRIGGS V-TWIN model 407777-0188-B1. Initial problem was the fuel pump stopped working and I replaced. After replacing and mowing a few times it then started to pop/backfire. I replaced the carburetor but problem did not change. I have since replaced the gas, the gas cap...
www.lawnmowerforum.com
I have been through a bunch of engine tests, which I'll list at the end, but I haven't been able to see anything but a healthy new engine. I finally took the carburetor off for inspection based on the forum post above having the wrong carburetor. The only thing I found was slightly damaged float bowl gasket (698781) on a round section that did not seal anything. I replaced the gasket just in case, but it still continues to afterfire. The carburetor was very clean and nothing else seemed to be restricted or damage. I cleaned the carb anyway but nothing has changed. I plan on inspecting the fuel delivery, but I'm pretty much stuck except for invasive exploratory disassembly of the engine (cylinder head, camshaft.)
I would appreciate any help with this issue because I'm losing sleep over this. The only thing that stops the popping
and afterfire is running on one cylinder. Thanks in advance.
[Engine Tests Performed]
static compression test
dynamic (running) compression test
leak down test
cylinder contribution test with tachometer
ignition spark tester check
ignition diode check
ignition armature corrosion cleaning
ignition armature gap check
spark plug condition and gap check
ignition wire leak check
swap ignition coils
smoke test intake
smoke test exhaust cylinder 2
visual inspect exhaust valve chamber cyl 2
PB Blaster LMT Cylinder 2
Sta-Bil Fix It
Seafoam in Gas
PB LMT through Intake
Valve lash adjusment .005 Int/Exh
Valve guide check
Bent Push Rod inspection
Valve movement check with both covers remove
Flywheel sheer key inspection
New spark plugs, air filter, fuel filter
Clean emulsion tube with wire and carb cleaner
Clean main jet with wire
Blew transfer tube with compressed air
Cleaned air inlets of carb with wire and carb cleaner
Blew carb air inlets with compressed air
Checked backfire solenoid
Inspected float bowl needle
Clean idle circuit with wire and carb cleaner