"spark Plug"

[skillman]

Just winterized my boat. I have twin 250hp saltwater 2 strokes. The boat ran fine before i put her away,as I took the spark plugs out to spray a little fogging oil in one of the motors one of the spark plugs were completly clean.All the other plugs looked normal.Does anyone know what might cause this? Any info would be greatly appreciated...thx

 

[Laddies]

Re: "spark Plug"

It sounds like it's not running on that cyl, check for spark and compression

 

[gss036]

Re: "spark Plug"

Either not firing or water injestion from head gasket leak.

 

[Texasmark]

Re: "spark Plug"

Or both.

Mark

 

[skillman]

Re: "spark Plug"

Would a comp test reveal a leaky head gasket if it were around a water jacket? Its getting arc to the plug i checked it this morning

 

[j_martin]

Re: "spark Plug"

Anything that will "steam clean" a spark plug is harmful to your engine. Lean mix will burn a piston. Rich to the point of cleaning the plug will cost power, and maybe put too much flame in the exhaust chest. Moisture from a bad head gasket, or a pinhole in the cylinder wall, or even from a back spray from a leak in the exhaust chest will eventually cause failure from oxidation or poor lubrication.

This is an early warning. Service now will prevent a major overhaul in the near future.

To answer your question. A compression test may show up a bad head gasket. A good result on a compression test, however, does not mean that all is well.

hope it helps
John

 

[skillman]

Re: "spark Plug"

Thx John,
I could have been running it like that for awhile,didnt notice anything wrong with the motor everything ran normal.But thx for your opinion,i'm gonna have a mechanic look at it tomorrow I just wanted a few good opinions on what it might be before I get raped by the mechanic...thx

 

[j_martin]

Re: "spark Plug"

One common thing that happens is a pinhole in the exhaust chest divider pees a fine stream back into the cylinder. That's relatively minor to fix. The mechanic can figure it out pretty quick with some moxey and a borescope.

If yer worried about the mechanic cheating you, it's time to find another.

good luck
John

 

[skillman]

Re: "spark Plug"

Mechanic was over yesterday & we went over everthing together. Could not find anything wrong. Did a leak down ,comp test again,put new plug in that cylinder and let engine run for about 15 staight min,pulled the plug out and it looked normal. So either it's doing it under a heavy load,or mabye when i changed plugs last time mabye i didnt have the boot all the way over the plug on that cylinder.....hmmm! Kinda a mystery to me!

 

[Don S]

Re: "spark Plug"

Or a faulty spark plug, wouldn't be the first. What kind of plugs did you have in it?

 

[skillman]

Re: "spark Plug"

Champion, think the # is QL77 it's what the manual states