# half of engine cold



## LawnAmbush (Jul 4, 2014)

My dear deere (john deere 316) began running rough. I cleaned the bowl of the carburetor and the jets but not the lower portion of the carburetor that controls idle. Upon restart, same symptoms. to dig into the lower portion of the carburetor I tore back into the engine but noticed half the engine was cool and the other half hot.

Previously I had pulled the plug wires off one at a time and the engine died. I thought this meant both cylinders were firing. The half cool condition means half isn't firing...but why would removal of the non-firing cylinder plug wire cause the engine to die? are the plugs connected electrically even if one isn't firing?

Thanks for any help!
What's the next step?


----------



## Country Boy (Mar 18, 2010)

I'd do a compression test on both cylinders and see if they are even. You can buy a gauge at an auto parts store. Pull one plug, screw it in the hole and crank it over (disconnect the other plug wire first). Then, do the other side. If the pressure varies by more than 10-20lbs from one side to the other, then you have some issues to deal with. Could be a stuck valve, bad rings, etc.


----------



## Mickey (Aug 14, 2010)

Both plugs are connected to the same coil. Both plugs fire each revolution. Pull a wire and neither plugs get any fire.


----------



## LawnAmbush (Jul 4, 2014)

Thanks for the input. I appreciate the knowledge about the coil. I've took your advice and checked the compression cold, and then checked it hot. both cylinders were within a couple pounds of each other. I swapped a plug that I was having poor spark. Both plugs are sparking well. the motor starts ok and runs with minimal hiccup for 5 mins and then trips up aggressively once it gets hot. the carburetor spits gas out of the top (into what would be the air filter if I reinstalled it) The single adjustment screw on the carburetor has no affect on the run condition. Do you think its time to tear into the bottom half (the idle control) half of the carburetor? When is it time to begin praying? thanks again.


----------

