mercury 1150 grayish plug

[fishdog4449]

hi yall. ran the 1150 for the first time since water pump change. ran fine, idled nicely. pulled the plugs to be sure all ok there.1,2,4,5,6 were all fine. number 3 had a grayish substance on the outer electrode. that felt like oil, but was gray in color. please tell me this is something other than water getting into the cylinder. if so, how could it be getting into just one cylinder?

 

[emckelvy]

Re: mercury 1150 grayish plug

Sounds like either the inner exhaust port water jacket cover or the exhaust baffle is leaking and spraying water into #3 cylinder.

 

[fishdog4449]

Re: mercury 1150 grayish plug

Is that something that needs to be fixed asap or will the motor run for a season or so like that? Also, is that something that requires disassembly of the powerhead?

 

[Benny1963]

Re: mercury 1150 grayish plug

yes you dont want water damage run a comp check to see if all your cyls are good

 

[fishdog4449]

Re: mercury 1150 grayish plug

here are compression results
1=121psi
2=135psi
3=130psi
4=135psi
5=135psi
6=135psi

well i was initially worried about the number 3 because of the odd looking plug...but seems number 1 may have some issues!

can one of you inline experts give me some feedback on these numbers?