removing corroded spark plugs

[joker111]

1996 Evinrude 6hp
should i use wdl 40
any tips

 

[bruceb58]

Re: removing corroded spark plugs

Soak with pb blaster.

 

[4JawChuck]

Re: removing corroded spark plugs

Do it with the engine warmed up on the muffs, not hot off a WOT throttle run. If they don't budge (be careful!) warm the area around the plug with a torch or hot air gun once the water clears out of the block off the muffs and give the plug base a shot of "Super Cold" to shrink the spark plug base shell, you may have to do it many times to break the corrosion bond. Once they start to move I like plain diesel fuel or A9 cutting lubricant but "Liquid Wrench" is a great wicking lubricant you can get off the shelf.

To be honest if you have never done this before I recommend you take it in and have an experienced professional marine mechanic or machine shop do it for you, stripped head plug threads are no fun and not cheap to fix unless you take the heads off yourself...and if you have an integral block (like my Merc 90HP) you would be in serious trouble.

I have a 100% success rate with the cold treatment and torch method and I have done hundreds of frozen plugs this way, the last set I did came out of a flathead Ford that sat in a farmers field for 40 years...I got them all out without stripping the threads but it took me most of a day to get all of them but those were steel plugs in badly corroded cast iron. The frozen pistons took another half day to get out without destroying the block or machining them out although I did drill a couple of relief holes in them.

Aluminum is very fragile and takes an experienced hand to do successfully, think about the investment you have in your motor before you attempt it yourself.

 

[wellsc1]

Re: removing corroded spark plugs

PB Blaster, PB Blaster, PB Blaster. I recommend PB Blaster. That's my subtle suggestion. It works when no other penetrant does, including Liquid Wrench and WD40.

When all the subtle solutions fail, then get incrementally more drastic - like the hot and cold method or pneumatic impact wrench on lowest torque setting. Worse case, you ruin the head and have to install heli-coils or replace the head.

After fixing it, periodically replace the plugs - more often if used in saltwater.

 

[wire2]

Re: removing corroded spark plugs

Once they're out, a dab of anti-seize on the threads of new ones will prevent the problem in the future.

 

[Splat]

Re: removing corroded spark plugs

WD40 is NOT a penetrant!

PB Blaster, or OpenShut, is what you'll want to use.

Bill

 

[joker111]

Re: removing corroded spark plugs

pb blaster did the trick - thanks

 

[stylesabu]

Re: removing corroded spark plugs

i have also used tap-a-socket, on bleeder screws for brakes.i this application,used the next smaller size socket. this will sit on top of the sparkplug nut. then tap on it with a small hammer, thr vibration breaks the bond between threads,and make sure you have sprayed pb buster first.this always works. if you can fin d the right size tap-a-socket it works even better as you can put a little pressure on sparkp[lug nut while tapping socket.glad you got it loose.

 

[Texasmark]

Re: removing corroded spark plugs

Since you got it fixed I would assume that you will not return to this post. But if you do, go to AutoZone and get a little pack of "plug anti-seize" (about $1) and apply some to the threads then reinstall.

I use PB Blaster too on rusted farm machinery and it works great. Also use Kroil which is excellent but not available in consumer stores.

Mark

 

[1946Zephyr]

Re: removing corroded spark plugs

Hmmmm, never had this problem before I change plugs periodically and it prevents it. Did you pick up this motor recently after sitting for years?

 

[F_R]

Re: removing corroded spark plugs

Hmmmm, never had this problem before I change plugs periodically and it prevents it. Did you pick up this motor recently after sitting for years?

Just what I was thinking. How in blazes did they get corroded in? There shouldn't be any water in there to cause corrosion. If there was, he has a lot more problems than just corroded plugs.

 

[1946Zephyr]

Re: removing corroded spark plugs

well, from my experience, a little oil will typically work itself around the spark plug threads from running and that should keep them from seizing to the plug holes. Like you said F_R there's a good chance that this motor could have been submerged and water got in the cylinders. Next question is, does the motor turn over freely? As a rule, a 1996 motor shouldn't have any plugs corroded in, unless water got in the cylinders.