Spark Plug Insulators-Broken

[Bugsy's Baits]

Found three of these in my 2000 225 EFI Merc. All pics of same plug. They show insulator thats broken and moved up and down center electrode. The pic where I bent the metal gap piece shows a circular wear mark on the bottom matching the shape of ceramic insulator.

Note.....when winterizing i did disconnect primer bulbs on both motors and run them out of fuel and i did two restarts on each motor. Could this cause erractic pulses to break insulators or did a sudden lean condition do this. Or is this a bad batch of plugs?

Motors have 330 hrs on them.

I will do a compression test in the spring when i move my boat out of storage.

Bugsy<o:p></o

[patchesII]

Detonation will break insulators. Could've done it when they ran out of fuel and had a real lean condition

[Dave Strong]

Could just be bad plugs. Running VST dry is very hard on the fuel pumps.

Dave

[Bugsy's Baits]

Ok thanks for tips. Didnt know running vst out of fuel was a bad thing. Should i just leave the fuel in the lines and vst.

patchesii/erik....have you seen broken insulators before?
Bugsy

[patchesII]

Yes I have. One time was written off as a bad batch of plugs. Other times were detonation. Dave is probably right, bad plugs

[Bugsy's Baits]

Do you think it's worth sending couple the plugs in to champion so they can look at them? it doesn't look like any big fragments came apart when the insulator broke....do you think I need to bore scope the tops of the pistons or the cylinder walls?

thanks again!

Bugsy

[Bugsy's Baits]

a lot of technicians that I talk to, as I am one myself, say a lot of bad things about Champion spark plugs.I would assume the other brands do this as well.

This pair of outboards are many comments or tips are much appreciated. Should I be changing spark plugs every season with only 20 to 50 hours of seasonal operation? I am very meticulous with my equipment but maybe I need to be more meticulous with spark plugs.....the only issue that I had with one of the motors was the lift pump diaphragm kit. That was about 2 seasons ago and I think it switch from a black rubber diaphragm to a white plastic Teflon diaphragm.....ethanol resistance.

I have spoken to Jay Smith JSRE a couple of times for some tech tips and for some oil recommendations.that man is a true gentleman and also very nice to talk to.

I am basically reaching out to the guys on this forum that have way more experience with outboards then i do. perhaps I'm doing a few things wrong and don't mind being told that I am....


I have a 30 foot trophy hard top that I use for salmon fishing in the Great Lakes region and I fish on Lake Michigan I do a lot of 2 mph trolling on one engine.

[pointer]

Personally, at 20 to 50 hrs a season I see no reason for new plugs.

I've had insulators break - too lean. I got lucky and had no detonation damage. I was tuning on the edge and knew it. At high RPM I could hear the miss.

pointer

[Bugsy's Baits]

Pointer.....could low speed....low rpm idling cause detonation which may be the cause. Does that plug look lean....not to me. Shows a lot of oil deposits...or ash residue.

Thanks !

Bugsy

[Dave Strong]

Never been a Champion plug fan but there are some applications they do work better than others.
Electric fuel pumps rely on fuel for cooling and lube somewhat. Most VST's have a drain screw on them.

Dave

[Bugsy's Baits]

Dave, now that's a good tip for the VST having a drain plug......duh!!! Lol

Thanks!

Bugsy

[Capt.Insane-o]

When you open a box of Champions look down the insulators and check out how many are actually centered in the shell. ;)

[XstreamVking]

I have had the center come out of a NGK plug on a 2.5 and it lunched the piston top. Just a bad plug. Never saw it before, or since. Lucky for me it was under warranty. 3 of them at once would make me suspicious.

[Bugsy's Baits]

Suspicious of bad plugs or engine cal/detonation issue.......

Could the low speed trolling cause this?

BUGSY

[XstreamVking]

That I don't know.....Could just be bad plugs, but I would check it out carefully when it's running again. I wouldn't think trolling would cause it.

[Bugsy's Baits]

How about an overdose of mercury quickleen......ive put it twice a season for the past 4 seasons.

Bugsy

[XstreamVking]

I use it in all my motors regularly, even my old stroked camaro. Not had a problem with quick clean. I wonder if someone may have been rough when setting the gap? Prying on the electrode to open the gap, instead of using the correct tool. Just my 2cts...