Spark plug problem

[TheSkinny]

Just to let you guys know how my lawn tractor adventure came out. Actually everything worked. I got everything finished and the tractor reassembled yesterday and the mower now runs better than new! I'm surprised since this was about my first foray ever into fixing a lawn tractor.

I do have some troubled thoughts about one aspect of the job and I'd like your comments.

When I chased the threads in the engine block my plan was to use a brush to clean out any metal shavings. I also planned to only do 1/8 turn at a time and back the tap out. First, it wasn't so clear cut since the tap never went smoothly in the hole and I was never quite sure where the problem started and where the threads straighted out. So I got a lot of shavings. The main thing I wonder about was the fact that I overestimated the size of the spark plug hole and the brush I used was too large. I have a feeling I probably pushed metal shavings into the engine when I put the brush in. I then got a smaller brush but figure it was too late.

However, I did get a lot of the shavings out with the smaller brush --- and at least for now the tractor is running beautifully.

I dont' really know for certain that I did push any shavings into the block but I'm just surmising I did. Questions-- If I did push a few shavings in how long would it take for me to start seeing problems with the engine? Anything I should do in the meantime to diminish any problems? Is this an inevitable problem? Should I just not worry about it since the engine is now running well and maybe I won't have any problems from this after all?

Thanks in advance for any comments,
Richard

 

[Fish]

Yeah, that grease on the chaser really works pretty good, you should have tried it.....Hell, Vaseline, butter, Crisco...... Better than metal shavings anyday....

 

[exotion]

Air compressor or dentist vac works good.

 

[TheSkinny]

Update on my lawn tractor situation:
I've used the mower twice now and it continues to run well. However, I have had a mysterious little episode that some of you might be able to comment on. The last time I was using the tractor I suddenly got a puff of thick blue smoke that I think came out of the muffler -- I'm not sure as the muffler comes out the front of the mower and I was sitting on it at the time. It seemed to be up front of the engine but it surprised me and I couldn't tell for sure. The smoke went away as fast as it appeared. The engine kept running and it seemed fine. About fifteen minutes later it happened again. Again the engine continued to run fine. It may have labored a second or so when the smoke appeared, but then everything seemed okay again.

It has never done anything like this before. Any ideas?

Thanks in advance.
Richard

 

[exotion]

Carbon deposits coming loose?

 

[motoman]

Skinny, Tips . Aluminum should not be heated. At 390F it softens and will not hold valve guides in place and threads will pull out. Carbon is depositied in the spark plug bore at the chamber side and works its way outward . This can be felt when screwing in a plug by hand. Sound like your situation was damaged threads. I NEVER START ANY FASTENER WITH A POWERED DRIVER OR A CRANK HANDLE. If the threads are ok , square up and slightly reverse the normal screw- in motion until you feel a slight drop. Then continue by hand clockwise (rt hand thread) until you feel the threads are engaged properly.

The experts tell us not to use a tap to chase threads because the tooth profile is too agressive and will weaken the threads. Of course I use taps, but it is like chiseling with and striking a screwdriver (I do this too)-don't do it if possible. A chaser is best. I put it on a socket and extension and try to complete the clean out by hand without a handle. Observe plug torque (e.g. 10-20 ft lbs ??) and reduce the torque if you lubricate. The galv surface is a lubricant itself . I usuallly squirt WD 40 onto the threads and dry the threads with rag.

Over the years I have often cut or ground on an engine with risk of entry. Sometimes you can plug (rag) and vacuum. The effect of chips dropping may not be catastrophic as some may have left on the first few engine cycles thru the exhaust port. Let's hope.:thumbsup:

 

[TheSkinny]

Yeah, that grease on the chaser really works pretty good, you should have tried it.....Hell, Vaseline, butter, Crisco...... Better than metal shavings anyday....

You're right. I should have tried that.
Richard

 

[TheSkinny]

Air compressor or dentist vac works good.

Interesting idea. A friend of mine told me (after the deed was done) a magnet works well. I'm sure that's a good idea with a steel engine. However,, I don't think aluminum is attracted to magnets. I'll have to try it.
Richard

 

[TheSkinny]

Carbon deposits coming loose?

You might be right. I would think this would be the most benign possibility. - Richard

 

[TheSkinny]

Skinny, Tips . Aluminum should not be heated. At 390F it softens and will not hold valve guides in place and threads will pull out. Carbon is depositied in the spark plug bore at the chamber side and works its way outward . This can be felt when screwing in a plug by hand. Sound like your situation was damaged threads. I NEVER START ANY FASTENER WITH A POWERED DRIVER OR A CRANK HANDLE. If the threads are ok , square up and slightly reverse the normal screw- in motion until you feel a slight drop. Then continue by hand clockwise (rt hand thread) until you feel the threads are engaged properly.

The experts tell us not to use a tap to chase threads because the tooth profile is too agressive and will weaken the threads. Of course I use taps, but it is like chiseling with and striking a screwdriver (I do this too)-don't do it if possible. A chaser is best. I put it on a socket and extension and try to complete the clean out by hand without a handle. Observe plug torque (e.g. 10-20 ft lbs ??) and reduce the torque if you lubricate. The galv surface is a lubricant itself . I usuallly squirt WD 40 onto the threads and dry the threads with rag.

Over the years I have often cut or ground on an engine with risk of entry. Sometimes you can plug (rag) and vacuum. The effect of chips dropping may not be catastrophic as some may have left on the first few engine cycles thru the exhaust port. Let's hope.:thumbsup:

These are good tips. I;m keeping them until I change my next spark plug. Thanks-Richard