Scooby074
Super Member
I have a older Craftsman 18Hp Lawn Tractor with the 18 HP Horizontal twin engine Model 422707.
This mower hasnt ran in at least 5 years. Originally i was having a problem with the mower blades hitting, see thread here : http://www.tractorbynet.com/forums/lawn-garden/144894-craftsman-garden-tractor-mower-blades.html
After fixing the blades, i noticed that the mower was running rich and was down on power when mowing heavy grass.
After troubleshooting, i noticed the RH cylinder had no spark and the plug was only warm, while the other cylinder had spark and the plug was hot. Unplugging the RH has essentially no effect on engine performance, but unplugging the LH plug ill result in a stalled engine.
I rotated plugs left to right and still the RH cylinder was dead, so i replaced the coil ($90)
Today i have a good spark on both plugs, but the RH cylinder still isnt firing.
Compression is good at 120PSI per side, so that rules out any cylinder or valve damage.
Ive checked the valve clearances, LH side is perfect, RH side is a little off.
RH Intake is 0.0085" , spec is 0.006" ; Exhaust is 0.010", spec is .009". Would the 0.0025" out of spec on the intake cause a no fire or intermittent fire situation??? I dont think so, so id like to know before i tear the cylinder head off and try to reduce that gap.
I cranked the engine, with the valve covers off, and all valves are opening smoothly.
Both plugs are getting very carboned up after a short (3-5 min) run. Of course the LH side is much more carboned up than the right. Neither plug smells like raw fuel.
The carb has been thoroughly cleaned.
After the last run of the day, when i shut the machine off, i noticed quite a bit of white smoke coming out of the carb. This lasted about a minute or 2.
Could a blocked exhaust pipe on the RH cylinder be the source of my issue? Putting my hand in front of the muffler, it feels like there is plenty of exhaust coming out.
This mower hasnt ran in at least 5 years. Originally i was having a problem with the mower blades hitting, see thread here : http://www.tractorbynet.com/forums/lawn-garden/144894-craftsman-garden-tractor-mower-blades.html
After fixing the blades, i noticed that the mower was running rich and was down on power when mowing heavy grass.
After troubleshooting, i noticed the RH cylinder had no spark and the plug was only warm, while the other cylinder had spark and the plug was hot. Unplugging the RH has essentially no effect on engine performance, but unplugging the LH plug ill result in a stalled engine.
I rotated plugs left to right and still the RH cylinder was dead, so i replaced the coil ($90)
Today i have a good spark on both plugs, but the RH cylinder still isnt firing.
Compression is good at 120PSI per side, so that rules out any cylinder or valve damage.
Ive checked the valve clearances, LH side is perfect, RH side is a little off.
RH Intake is 0.0085" , spec is 0.006" ; Exhaust is 0.010", spec is .009". Would the 0.0025" out of spec on the intake cause a no fire or intermittent fire situation??? I dont think so, so id like to know before i tear the cylinder head off and try to reduce that gap.
I cranked the engine, with the valve covers off, and all valves are opening smoothly.
Both plugs are getting very carboned up after a short (3-5 min) run. Of course the LH side is much more carboned up than the right. Neither plug smells like raw fuel.
The carb has been thoroughly cleaned.
After the last run of the day, when i shut the machine off, i noticed quite a bit of white smoke coming out of the carb. This lasted about a minute or 2.
Could a blocked exhaust pipe on the RH cylinder be the source of my issue? Putting my hand in front of the muffler, it feels like there is plenty of exhaust coming out.