New coil, New plug, no spark?

[forrest]

Howdy,

My neighbor has 2001 snapper riding mower with a Briggs and Stratton 18HP V-twin Vanguard engine model number: 350777-1143-E1.The left cylinder stopped working so he bought a new coil ( briggs and Stratton part number 492341) he installed the coil and a new plug but the cylinder still isn`t firing. He said the plug wire on the new coil gets too hot to touch after running the engine for only a few minutes.He said he put the old coil from the right cylinder on the left cylinder and it fired fine,he also said that when he touched the hot plug wire on the new coil he got shocked.
I haven`t confirmed any of what he said yet but I do know that he got the correct coil part 492341 so I don`t think the problem is from the wrong coil.
I thought maybe the problem is with the kill switch or the kill wire on the coils but why would one coil fire and the other one doesn`t?
He said he pulled the plug and connected the new coil wire to it and started the engine but didn`t see the plug sparking.He claims the coil works because when he touched the plug wire while the engine was running he got a shocked I told him to adjust the plug gap and check the gap between the flywheel and the coil.He said he checked all that and it still won`t fire.

When he gets home I`m going to go over there to see exactly what`s going on with the mower because it just doesn`t seem possible that one coil could be working while the other coil (the new one) doesn`t work.

Any ideas?

 

[ILENGINE]

There is a single wire kill wire that goes to both coils. There should be a diode between the coils. If that diode goes bad you will loose fire. Try running it with the wires disconnected from the coils and see what happens.

 

[forrest]

There is a single wire kill wire that goes to both coils. There should be a diode between the coils. If that diode goes bad you will loose fire. Try running it with the wires disconnected from the coils and see what happens.

I went over there today to take a look at it and basically everything he told me was incorrect, lol.

The first thing I did was remove the plug and connect the coil wire to to the plug, then I started the engine and surprise, the plug was firing fine,even on a bright sunny day like today I could clearly see a nice blue spark in the plug gap. The wire didn`t get hot, and I didn`t get shocked when I touched it.The new plug was black with some unburned gas on it and there was a lot of smoke coming out of the muffler that smelled like gas.
My first thought was(stuck exhaust valve) so I pulled the cover off the valves and immediately noticed that the exhaust valve was stuck wide open.We removed the head and had to use a punch and a hammer to pound the valve out.There isn`t any noticeable bend in the valve stem but it was wedged in there pretty good so I ordered him a new valve.

I learned a valuable lesson today, never believe what people tell you always check things out first hand.Now I`m left wondering if he actually checked the things I told him to check or if he was so convinced that it was the coil that he didn`t even bother to check anything else.
I guess I shouldn`t be so hard on him he`s 70 years old and might be getting senile but damn! how could he be so wrong about everything that he claimed?

 

[ILENGINE]

Now take all the information that you just discovered about what had been done or not done, and then apply that to the average customer we deal with on a daily basis, and consider that as part of warranty, and then you discover why dealers don't believe what there customers are telling them happened.

 

[forrest]

Now take all the information that you just discovered about what had been done or not done, and then apply that to the average customer we deal with on a daily basis, and consider that as part of warranty, and then you discover why dealers don't believe what there customers are telling them happened.

I definitely have a lot more respect and sympathy for the dealers and repair folks now.