1977 Chrysler 135 - is spark plug too clean -possible gasket issue

[seattle scott]

I'm getting 120 PSI compression all cylinders and have run the motor for a couple of hours on the boat, probebly 3/4 the time in the no wake zone so low RPMs. Runs perfect at WOT but has a periodic hickup, mabe every minute, when running slow ( no tach) and idles OK. But all the plugs are staying "clean", no soot, just a liquid film and that wipes off. I have heard that this is a sign of being "washed" by water/steam caused by a gasket leak. Should I do a gasket replacement? Is the fact that all plugs look the same odd or indicates not a gasket problem?

 

[tater76]

Re: 1977 Chrysler 135 - is spark plug too clean -possible gasket issue

Number two pic looks very normal, number one?? It doesn't look pressure washed/steam cleaned, but not quite dirty enough for me. You can pull the head and see if there is any moisture in that cylinder. If there is the exhaust gasket may have failed on this cylinder. The real PIA is that i'm sure your exhaust plate is home to MANY corroded stuck bolts. In the perfect world you could take the exhaust plate off and inspect the gasket. Like I said though, take the head off after running it and you may find water inside??

 

[seattle scott]

Re: 1977 Chrysler 135 - is spark plug too clean -possible gasket issue

Number two pic looks very normal, number one?? It doesn't look pressure washed/steam cleaned, but not quite dirty enough for me. You can pull the head and see if there is any moisture in that cylinder. If there is the exhaust gasket may have failed on this cylinder. The real PIA is that i'm sure your exhaust plate is home to MANY corroded stuck bolts. In the perfect world you could take the exhaust plate off and inspect the gasket. Like I said though, take the head off after running it and you may find water inside??

the photos are of the same plug, I just ran my finger across the "dirty" plug and took another photo. All the plugs are identical.

 

[bman1bpm]

Re: 1977 Chrysler 135 - is spark plug too clean -possible gasket issue

if thats the case your plug looks fine. A few hickups at idle are fine, its better to have your motor run rich at idle than it is to have it lean out and melt pistons from detonation at WOT

 

[seattle scott]

Re: 1977 Chrysler 135 - is spark plug too clean -possible gasket issue

I guess I worry too much. I am new to this whole 2 stroke machine.