new rings and spark plugs too clean??

[Alumarine]

Just fired up my newly re-ringed mercruiser 140.<br />Ran it for 15 minutes at 1500 rpm. Tried to bring it up to 2000 but had a slight miss. Oil pressure and temp ok. Timing ok. Pulled plugs and checked compression.<br />#1 150 psi plug was a nice tan<br />#2 150 psi plug was slightly black<br />#3 131 psi plug ceramic was slightly discolored electrode was silver - like new<br />#4 131 psi plug ceramic was slightly discolored electrode was silver - like new<br />I'm not too concerned about the compression of 3 and 4 after only 15 minutes of running but am curious why the plugs look like new?<br />I may not have adjusted the valves properly. I'm a complete idiot when it comes to hydraulic valves, all my experience has been with solid lifters.

 

[Dunaruna]

Re: new rings and spark plugs too clean??

Gotta give those rings time to bed in, 15 minutes just ain't enough time. Loading the motor helps (but not too much), on the water (in gear) with light and varied throttle.<br /><br />Carby clean? New fuel filter? NEW OIL?<br /><br />Aldo

 

[Alumarine]

Re: new rings and spark plugs too clean??

Why would plugs 3&4 still look like new?<br />Carb's clean, new fuel filters, new oil and filter. Yes, I think the compression will come up.

 

[Dunaruna]

Re: new rings and spark plugs too clean??

Rings not spaced the same as the other two cylinders, crosshatching not exactly the same, poor quality machining inside the manifolds (not 'tuned'), different length spark plug leads and therfore weaker/stronger spark, minute vac leak on one or two pots, dust got in, condensation got in, slightly binding valves/guides, cam lobes not worn evenly........................<br /><br />Don't worry about it, bed it in and then retest your comps.<br /><br />Aldo

 

[Alumarine]

Re: new rings and spark plugs too clean??

Thanks everyone. I'll run er some more and see how things are. May take it in to get the valves adjusted later although they sound good.