JINMA224XR
Gold Member
- Joined
- Feb 27, 2005
- Messages
- 464
- Location
- Alabama Gulf Coast
- Tractor
- 2004 JINMA 224XR, (1990 SHINNIU 254/sold)
<font color="blue">If I run them at higher RPM's (mowing) but don't let it idle for a few minutes before shutting them off, they let off one heck of a backfire. </font>
Hey bczoom,
Explosion in the exhaust is a result of unspent fuel, hitting the hot exhaust.
It may be a result of the carburetor being set too rich. Or a dirty air filter. I would pull the plugs on a cold engine and inspect the Sparkplug insulator's color. Perfect color is slightly tan. Too rich and the ceramic insulator will be dark. If so, make sure that your air filter is clean and/or adjust your Fuel/Air Mixture.
On the bigger engines, it may also have something to do with the Exhaust Emission System as well. On some Motorcycle Engines, there is a fresh air inlet valve that leads into the exhaust chamber to fool the EPA EXPERTS, into thinking that the engine is burning cleaner, but in actualality, it is just diluting the unspent gas with more air. /forums/images/graemlins/smile.gif When that air inlet valve leaks a little bit, upon shutdown, it will provide fresh oxygen to a little bit of unspent exhaust gase and cause an explosion as well. On my Motorcycle, I stuffed a bearing up into the hose just prior to the air inlet valve going into the exhaust side of the head. It took me a long time to figure that one out. /forums/images/graemlins/smile.gif
At any rate, an explosion in the exhaust system is not helpful to any engine and a remedy should be found, before noticeable engine damage results.
Have a nice day,
Joe/forums/images/graemlins/cool.gif
Hey bczoom,
Explosion in the exhaust is a result of unspent fuel, hitting the hot exhaust.
It may be a result of the carburetor being set too rich. Or a dirty air filter. I would pull the plugs on a cold engine and inspect the Sparkplug insulator's color. Perfect color is slightly tan. Too rich and the ceramic insulator will be dark. If so, make sure that your air filter is clean and/or adjust your Fuel/Air Mixture.
On the bigger engines, it may also have something to do with the Exhaust Emission System as well. On some Motorcycle Engines, there is a fresh air inlet valve that leads into the exhaust chamber to fool the EPA EXPERTS, into thinking that the engine is burning cleaner, but in actualality, it is just diluting the unspent gas with more air. /forums/images/graemlins/smile.gif When that air inlet valve leaks a little bit, upon shutdown, it will provide fresh oxygen to a little bit of unspent exhaust gase and cause an explosion as well. On my Motorcycle, I stuffed a bearing up into the hose just prior to the air inlet valve going into the exhaust side of the head. It took me a long time to figure that one out. /forums/images/graemlins/smile.gif
At any rate, an explosion in the exhaust system is not helpful to any engine and a remedy should be found, before noticeable engine damage results.
Have a nice day,
Joe/forums/images/graemlins/cool.gif