side that was not getting had pressure of 150 psi set valves at .005
briggs and stratton 25hp valve cover not heating up evenly
- Thread starter ACF
- Start date
Just to confirm:
Are all of these confirmed?????
You say it appears the left cylinder is running cold and not producing power when you pull the spark plug wire? (I usually just slide the rubber plugs boot back and ground the spark plug wire tips with a insulated handle screwdriver)
You have changed the magneto and you also see spark at the spark plug?
You compared the right cylinder compression to the left side as close to the same????
You swapped the spark plugs or installed a new spark plug and still no power on the left side?
THE ENGINE DIES WHEN YOU PULL THE RIGHT SIDE SPARK PLUG WIRE?
You adjusted the valve lash per specs?
A IR thermometer is really handy for comparing cylinder balance by reading the exhaust temps of each cylinder. The weak cylinder will usually be colder as compared to the good cylinders on a small gasoline engine.
If the above are confirmed try adding little bit of fuel as suggested in post 18.
Are all of these confirmed?????
You say it appears the left cylinder is running cold and not producing power when you pull the spark plug wire? (I usually just slide the rubber plugs boot back and ground the spark plug wire tips with a insulated handle screwdriver)
You have changed the magneto and you also see spark at the spark plug?
You compared the right cylinder compression to the left side as close to the same????
You swapped the spark plugs or installed a new spark plug and still no power on the left side?
THE ENGINE DIES WHEN YOU PULL THE RIGHT SIDE SPARK PLUG WIRE?
You adjusted the valve lash per specs?
A IR thermometer is really handy for comparing cylinder balance by reading the exhaust temps of each cylinder. The weak cylinder will usually be colder as compared to the good cylinders on a small gasoline engine.
If the above are confirmed try adding little bit of fuel as suggested in post 18.
ust to confirm:
when throttle is increased the engine starts surging/hunting with both coils connected
with the left side plug wire disconnected the right side will heat up.
tried the spray of intake connection no change in rpm
did just do a check of ground wire and ground wire coming from the right side cold side has a connection or maybe diaode that has a protective coating on it and from both ends of this coating there small beads of rubber/plastic coming from it could this be the diaode, and with the melted rubber it be bad causing problems
sitting on the mower the compression on left side is130 psi hot side on the right side cold side it is 135 psi. mower has spark on both coils, with ground connected or not connected. mower starts with ground wire disconnected and will stop when key switch is turned off.
when throttle is increased the engine starts surging/hunting with both coils connected
with the left side plug wire disconnected the right side will heat up.
tried the spray of intake connection no change in rpm
did just do a check of ground wire and ground wire coming from the right side cold side has a connection or maybe diaode that has a protective coating on it and from both ends of this coating there small beads of rubber/plastic coming from it could this be the diaode, and with the melted rubber it be bad causing problems
Yes the kill wire wiring harness on the twin OHV's has blocking diodes in EACH magneto wire. If one DIODE is shorted the ignition will be upset.
First see if the engine will start with the right side plug wire off?
Another test is remove the air shroud and disconnect both kill wires at the MAGNETOS. Be aware if you start the engine with both kill wires disconnected you will have to pull plug wires to kill the engine. (choking will not always kill the engine)
Do not test run the engine over 15 seconds with the air shroud off or it WILL OVERHEAT.
First see if the engine will start with the right side plug wire off?
Another test is remove the air shroud and disconnect both kill wires at the MAGNETOS. Be aware if you start the engine with both kill wires disconnected you will have to pull plug wires to kill the engine. (choking will not always kill the engine)
Do not test run the engine over 15 seconds with the air shroud off or it WILL OVERHEAT.
engine will start with right side plug wire removed
engine will start and stop using key with both kill wires disconnected
You say:
engine will start and stop using key with both kill wires disconnected
Wow. It's possessed!!!!!!!!!!!!!!
www.merriam-webster.com
engine will start and stop using key with both kill wires disconnected
Wow. It's possessed!!!!!!!!!!!!!!
Definition of POSSESSED
influenced or controlled by something (such as an evil spirit, a passion, or an idea); mad, crazed; urgently desirous to do or have something… See the full definition
www.merriam-webster.com
Hammermechanicman
Lawn Addict
- Joined
- Jan 10, 2020
- Threads
- 65
- Messages
- 3,828
I overlooked the after fire solenoid for turning the fuel supply on off)
Did the engine run smooth with both kill wires disconnected from the Mags?
Or did you detect any change at all?
Did the engine run smooth with both kill wires disconnected from the Mags?
Or did you detect any change at all?
Last edited:
replaed the wiring harness and there was not any change the left side valve cover got hot and right side was just warm rechecked the valve clearance and they are within specs, not sure what to do now totally lost
changed the coils around placed the one on the right to the left side and the one on left to the right side. started both valves covers heated up but did have surging when throttle pushed passed half way point but when under load there is no surging,