check my KT17 trouble shooting

[GWGAllisfan 142]

 I was mowing with my GT17L, (KT17 series II) and toward the end of the mowing, it started to be low on power and really run rough with vibration when heavily loaded.  I was able to finish, but then after cleaning the grass and dust off, I was trying to figure out what was wrong. a primitive cylinder misfire test (spit on each exhaust pipe and judge the sizzle) showed the right cylinder was cooler than the left. I removed that plug and it looked normal.  Swapped the plugs, and it still ran the same, so unlikely to be bad plug.

 I pulled the right plug wire it would run slightly weaker, but still run.

Pull the left plug wire. it would sputter to a stop.

At this point I thought it could be the cylinder,  But decide one more test. I swapped the plug wires at the coil. The problem swapped sides... So I'm thinking this is a bad coil. Before I spent the 100 for a new coil, I thought I would ask the experts.

Opinions? Anyone?

Edited June 5, 2018 by GWGAllisfan
Grammar issues

[Brettw 1,020]

It is my understanding that both plugs fire every time the coil fires.  So if you do have a cylinder running well, and one not, and it's not plugs, it may be the plug wire?  I could be wrong about the both firing, but I believe this is correct.  can the coild wire be replaced and save you some big bux?  I would try that if possible, first.

[GWGAllisfan 142]

I can try new plug wires, but how would that explain the observation that swapping the plug leads at the coil moves the problem from one side to the other?

[PhanDad 3,251]

3 hours ago, GWGAllisfan said:

how would that explain the observation that swapping the plug leads at the coil moves the problem from one side to the other?

Problem following the bad plug wire.

[MikeES 417]

VOM the coil.  Primary 4-5 ohms, Secondary 9500-11,500 ohms.

[GWGAllisfan 142]

I bought a coil, while I had a 20% off online coupon, , but also checked the old coil with the ohmeter. Primary around 4.7.  Secondary i could not get to read at all, no matter what setting I put the meter on.

 I’ve installed the new coil, and it runs much more even. We’ll see what happens at full temperature after mowing.

Edited June 9, 2018 by GWGAllisfan

[Kenh 35]

The points condenser can have a huge effect on how the engine runs.  A poor or bad condenser can have a detrimental effect on the coil.  Usually a bad condenser will show up at high RPM or heavy load on the engine.   If swapping plug wires and the problem follows the wire then the wire is the problem.  It's the same as swapping spark plugs and the problem follows the bad spark plug.  

 

Ken

[GWGAllisfan 142]

OK Guys,  you have me confused and concerned now.

With the old coil: If I swapped the plug wires at the coil, the problem moved, not with the wire, but with the coil tower. This was no matter which spark plug was on which side. I just don't see how that could be a wire issue.

With the new coil:  The engine runs much better, no missing or vibration to speak of, and if you remove a plug wire , either of them, the engine runs rougher, but the same degree of rough on each side. It has new wires so that rules the wire issue out.

I mowed the entire yard, except 150 feet, since PTO belt broke, but there was none of the issue I had felt before.

Also the new coil must have hotter spark, since I got shocked pulling the plug wire while running (using insulated plug pliers) with it on the engine, and didn't with the old one.

 

[PhanDad 3,251]

2 hours ago, GWGAllisfan said:

OK Guys,  you have me confused and concerned now.

Don’t be.

My bad.  I didn’t read your words closely enough.

You originally wrote: “I swapped the plug wires at the coil. The problem swapped sides...”

Brain missed the “at the coil”.  Makes a big difference.  

True communication can be very difficult at times.