What does this spark plug tell you?

[Solittle]

I am in the process of trying to get my 1988 1.6L V-4 OMC crossflow back in service after sitting for over a year. I put new plugs in it and went out for 45 minutes or so at 1500 rpms and 5-10 minutes at WOT. I pulled the plugs when I got back and on the starboard bank the upper plug looked OK. The lower does not. Here they are - what do you think?

 

[kenmyfam]

Re: What does this spark plug tell you?

Just my opinion but to me it looks like it is running hot, lean or both.

 

[Benny1963]

Re: What does this spark plug tell you?

look lean and the litle bit of rust is funny is that aluminum on that plug.
and by the way how are ya

 

[jtcarter]

Re: What does this spark plug tell you?

Lean

 

[ezeke]

Re: What does this spark plug tell you?

Looks like water sat there for a while.

Can't see, but if it were overheating the electrode should be deteriorated somewhat. If you were running lean, you would probably see some sign on the piston face in addition to aluminum on the electrode.

 

[jtexas]

Re: What does this spark plug tell you?

hotter than a 2 dollar pistol.

could that be pre-ignition?

 

[samo_ott]

Re: What does this spark plug tell you?

Hard to believe that plug is less than a hour old! Sure looks hot and/or lean.

 

[Solittle]

Re: What does this spark plug tell you?

look lean and the litle bit of rust is funny is that aluminum on that plug.
and by the way how are ya

Lets get to the funny looking plug first. I did a compression check this morning and the news ain't good. That hole has ZERO compression so from the looks of the plug and no compression I guess I got a hole in the piston. What I did not mention in my post was this engine got hot at WOT.

I'm not sure on what I'm going to do yet as I don't know if I'm up for doing a rebuild. I'm going to get a price from a locqal shop and check some other options. I would like to repower but the cost may be a lot more than I want to get into. This engine is one of a pair of 1988 SeaDrives I have on my 23' center console. For grins I got an estimeate at the Miami boat show for a repower. By the time you get the bracket, glass work, instruments, rigging and engine I would be looking at around $20K.

Benny1963 - You asked how am I - - I kinda thought that most guys who post here would have long forgotten about SoLittle as I have not posted much in the last 1 1/2 years so thanks for asking.

Last year I had to deal with lung cancer, the operation, the chemo and the recovery. I am back on my feet - sorta - now and the cancer has not spread so far. I was hoping to get back to boating fairly regularly and was on a test run when this problem came up. I retired in December 2007 and found out about the cancer at the same time. The cancer put my plans on hold to spend long weekends on Biscayne Bay and down to the Keys.

Life is a challenge!!!!