mower starts only when spark plug connection is removed but near (picture attached)

[stevenisam]

By holding the spark plug wire at a distance, in effect, you have created a "booster gap" spark plug:

Thank you, that's a good read.

 

[stevenisam]

Modern fuel, which is nothing like petrol , is very conductive at cylinder pressures.
Thus the spark will run down the side and ground out at the bottom of the insulator rather than jump the gap.
Holding the lead off the plug forces the voltage to build up to a higher amount before it can get to ground through the plug thus when the higher voltage hits the electrode it will jump the gap & fire the engine.
If your carb is flooding the engine then the plug will always be wet.
An old adage goes
Most ignition problems start in he carburettor
Most carburettor problems start in the ignition.

A magneto does not produce a fixed voltage, the voltage varies with the speed the magnets pass the coil .
Most of them will spark well before peak voltage is reached.

Thank bertsmobile, that's a sound explanation. Will keep this in mind about spark plugs.

 

[stevenisam]

Steven can you post a pic of the mower it's on ??? I remember the old Yazoo mowers with the horizontal Briggs on them.......

Great bullet proof mowers......

Plus Tard Mon Ami ~!~!

here is the picture.

 

[Boudreaux In Eunice La.]

Wow you got a good one right there... I love those old reel mowers.... My non'c had one when I was a small kid and couldn't push it..... It was a self propelled of course... That means by your self and no engine......

He bought that thing in the 40's after he got out of WWII........... I wish I had it today.............

 

[stevenisam]

That is because you have either the wrong plug or the plug has gone bad.
Run the engine for about 10 minutes then cut off the fuel supply to stop the engine.
Replace the plug lead & try again.
If no joy double check the plug.
Most engines with a hall effect triggered magneto take a resistor plug where as points ignitions generally use a plain plug ( no R in the grade ).

You were right, looks like the plug has gone bad. I changed it to another CJ8 plug and it did start with starter fuild. it was still emitting black smoke. I removed the air filter and the smoke disappeared. So looks like the air filter is blocking inflow of air and the gas is not getting enough air to burn. I couldn't find a replacement air filter locally, so went ahead and cleaned it for now. I also looked at the engine replacement parts and found that it needs a RJ19LM plug, so changed the plug to First Fire FF-10 which seems to be the replacement plug for RJ19LM. It still needs a starter fluid when cold but it started on first pull once warmed up.

Like mentioned in this forum, the carb might need a clean up but I am afraid to touch it, so if it works with starter fluid, I will continue to use it.

Thanks again to everyone who pitched in.

 

[Boudreaux In Eunice La.]

Please don't use starting fluid in your engine... Just use some carb cleaner...... It's easier on your engine....... A kit is cheap and easy to replace .......

Plus Tard Mon Ami ~!~!

 

[Boudreaux In Eunice La.]

You were right, looks like the plug has gone bad. I changed it to another CJ8 plug and it did start with starter fuild. it was still emitting black smoke. I removed the air filter and the smoke disappeared. So looks like the air filter is blocking inflow of air and the gas is not getting enough air to burn. I couldn't find a replacement air filter locally, so went ahead and cleaned it for now. I also looked at the engine replacement parts and found that it needs a RJ19LM plug, so changed the plug to First Fire FF-10 which seems to be the replacement plug for RJ19LM. It still needs a starter fluid when cold but it started on first pull once warmed up.

Like mentioned in this forum, the carb might need a clean up but I am afraid to touch it, so if it works with starter fluid, I will continue to use it.

Thanks again to everyone who pitched in.

An update would be nice....... How is it running for ya ?????

 

[sgkent]

put the old plug back in and see if it will run with that.