possibly water in cly. and spark plug gap closed

[merc150]

So went to change my plugs on my 2003 150 v6 carb motor and when I pulled the number one spark plug out I noticed the gap was closed almost to 0.10 gap and also noticed a little bit of water/oil on the plug (prolly head gasket) I did not see any marks at all on the piston. We have been chasing a running hot problem (185 degrees at WOT for the past year also temp likes to go up to 190 195 at 1500 to 2500 rpms). My question is would water in the cylinder cause detination that will end up closing the gap?? The reason for changing the spark plugs is bc they have been in there for 2 years and has a little miss while getting on plane. The last time I took the boat out I notice a very little tapping/zapping noise sound at idle only (sounded just like a arcing plug wire but Ive checked all the plug wires and theres not any cracks of arcing going on). I definitly do not have any rod knocks at all. other than all that the motor has about 450 500 hours on it and it has not been beat on and is very well maintained and runs like a beast. Im hoping it just the head gasket causing detination closing the gap. What do you guys think? :facepalm:

 

[Faztbullet]

Re: possibly water in cly. and spark plug gap closed

I have never seen water in cylinder close a gap, usually some mechanical failure closes gap....

 

[Mi duckdown]

Re: possibly water in cly. and spark plug gap closed

^+1

 

[merc150]

Re: possibly water in cyl. and spark plug gap closed

Re: possibly water in cyl. and spark plug gap closed

^+1

Just talked to my merc mechanic he saying sounds like theres a exhaust leak which would cause water in the cylinder and also cause the overheating issue. He told me to change the spark plug and run the motor on the muffs for 10 minutes pull the plug back out and check it again so ill give that a try later today and see what happens opcorn:

 

[merc150]

Re: possibly water in cyl. and spark plug gap closed

Re: possibly water in cyl. and spark plug gap closed

Just talked to my merc mechanic he saying sounds like theres a exhaust leak which would cause water in the cylinder and also cause the overheating issue. He told me to change the spark plug and run the motor on the muffs for 10 minutes pull the plug back out and check it again so ill give that a try later today and see what happens opcorn:

well I went to my boat today changed out the bad spark plug with a new one. Ran the motor on muffs for 20 minutes shut it off pulled the plug and it was fine. I did this twice and revved the motor up a few times trying to see if the piston is actually hitting the plug and its not. Motor ran smooth and quite. I may have had a little water in the gas filled my tank a few weeks ago from shell and the gas smells stail:mad-new: im gonna take the boat out for a test run tomorrow and see what happens

 

[wired247]

Re: possibly water in cly. and spark plug gap closed

Only thing Ive ever had close a gap was errant pieces of the piston. Your mileage may vary.

 

[Dukedog]

Re: possibly water in cly. and spark plug gap closed

If it had enough water in it ta close tha gap ya woulda had a rod hangin' "outside" also! Pretty much had ta be put in that way........

 

[CharlieB]

Re: possibly water in cly. and spark plug gap closed

I seriously suspect that the plug gap was closed by someone mis-handling the plug prior to installation.

If the piston closed the gap you would know it as the motor would have a serious noise and tried to dis-assemble itself at WOT.

If you have water getting into a cyl, FIX IT.

Do not continue to run the motor as it WILL get more expensive to repair, and soon.

Never put off a water problem unless you are in the market for a new motor.

 

[merc150]

Re: possibly water in cly. and spark plug gap closed

I seriously suspect that the plug gap was closed by someone mis-handling the plug prior to installation.

If the piston closed the gap you would know it as the motor would have a serious noise and tried to dis-assemble itself at WOT.

If you have water getting into a cyl, FIX IT.

Do not continue to run the motor as it WILL get more expensive to repair, and soon.

Never put off a water problem unless you are in the market for a new motor.

Yeah Im starting to wonder if I forgot to gap the plug or I dropped it or something when I put it in 2 years ago because its running fine now theres no knocking or any strange noises. My water/fuel seperator has a clear drain cap at the bottom it was full so im thinking so water along with fuel/oil (I premix 50 to 1) went passed it and the plug could barely fire to burn it off.

 

[merc150]

Re: possibly water in cly. and spark plug gap closed

I got 50 gallons of weak watery gas from shell....gonna pump it with a electric holley car fuel pump

 

[CharlieB]

Re: possibly water in cly. and spark plug gap closed

If you are getting water into a cyl from a leaking exhaust gasket that new plug and the piston top should be 'steam cleaned'.

Inspect soon, as continued use with water in there will cause a problem with steel piston rings and the steel cyl sleeve.

 

[merc150]

Re: possibly water in cly. and spark plug gap closed

If you are getting water into a cyl from a leaking exhaust gasket that new plug and the piston top should be 'steam cleaned'.

Inspect soon, as continued use with water in there will cause a problem with steel piston rings and the steel cyl sleeve.

The top of the piston wasnt clean it had some normal carbon build up on it (about just as much carbon that all the other cylinders have). I ran the boat for 45 minutes ran good pulled the spark plug back out and it looked fine. I guess all is good. I also did a compression check the numbers are 123 123 123 123 124 126. Which is really good. Anybody ever hear of a piece of carbon breaking loose and hitting the plug? Thats the only thing I can think of that may have caused the original plug gap to close to 0.10

 

[Big Fish Billy]

Re: possibly water in cly. and spark plug gap closed

My guess from way out here is you or someone else dropped the plug before you put it in, happens sometimes....