Spark Plug Opinions

[Propflux01]

90 hours. I've never had to add oil. Plugs look a bit rich to me. FS600V. Choke fully retracted. Runs seemingly normal. No smoke (black or blue) when running or accelerating. Thoughts?

 

[txmowman]

No, these plugs look typical for the most part. Overheated, if anything, not rich. Rich running would be dark black soot (unburned fuel), all over the porcelain and threads, that could be wiped off.

 

[Propflux01]

No, these plugs look typical for the most part. Overheated, if anything, not rich. Rich running would be dark black soot (unburned fuel), all over the porcelain and threads, that could be wiped off.

The one on the left I could see, but the one on the right shouldn’t be that black, should it?

 

[Auto Doc's]

I would replace the plugs with new ones (I prefer genuine Champion plugs from a parts store, not Amazon). If it's been running good keep going. A V-twin Kawasaki is a good engine.

 

[txmowman]

Agree with @Auto Doc's, replace them if you are in question.

 

[Propflux01]

They will be replaced. I was mainly concerned with their appearance.

 

[Auto Doc's]

The one with the whitest porcelain could mean a condition that is a little lean on the fuel mixture. The darker one is an indication of incomplete fuel burn and glazing, that usually ends up being an issue with the spark plug heat range or the resistor in the plug is starting to give out.

Are both plugs the same part number? What brand are they? Is this a single throat carburetor or a dual throat?

If it is a dual throat carburetor, manufacturers typically install 2 different main jets for reasons related to proper cylinder cooling and power balance.

On a maintenance note, it is very important to remove the top cover and any shields on occasion and blow all the dirt and grass chaff out of the cylinder fins. Plugged up cooling fins is a quick way to create overheating damage on small engines.

 

[Propflux01]

Yes, both NGK BPR4ES. Single throat carb.

No FOD in the cooling fin area.

 

[Auto Doc's]

Yes, both NGK BPR4ES. Single throat carb.

No FOD in the cooling fin area.

FOD? Wow! That is a military term I have not heard for a while.

Like I mentioned earlier, I would use Champion plugs. They should be RN12YC but double check the application number.

 

[Propflux01]

FOD? Wow! That is a military term I have not heard for a while.

Like I mentioned earlier, I would use Champion plugs. They should be RN12YC but double check the application number.

Comes back to haunt ya! lol!

Will do. Is there any reason you prefer the champs over the NGK's?