white powder around spark plug

[so]

hi,

got my first boat and the outboard is a 83 v4 evinrude 90 hp. I want to change the spark plugs.

When pulling out the spark plug from cylinder 1, I saw some white powder around the outer area where the plug sits on, is this normal or is it from overheat? the ceramic around the center electrode is the normal grey color but the top of the thread surrounding the ceramic shows black flaky deposits, plus the threads are a little sooty with oil, does that mean it's running too rich? it has vro.

cylinder 2 to 4 don't have the white powder in the outer area but have a little bit of oil. Plus, the original paint around head gasket on #1 and #3 is completely gone and shows a little bit of corrosion while #2 and #4 still have very good paint. is this overheat indication? why the difference bwtn the two banks?

p.s., It ran pretty good when I took it out few weeks ago.

any guidance is appreicated. thanks.

stan

 

[Solittle]

Re: white powder around spark plug

Since this is a new engine to you I would start by doing a compression check. That will give you a pretty good idea of what is going on inside. Then put the new plugs in, run it a time or two and pull the plugs again and look for differences between them. They should all look pretty much the same. Is this a salt water engine?

There are a bunch of other things you should do to that engine if you want to keep it in top condition - - like decarb, water pump, tstats, gear oil, check the temperature alarm, general lube and so on - -

 

[F_R]

Re: white powder around spark plug

Some oil on the plugs is expected. It is the oil that is being injected by the vro to lubricate the engine. If there were no oil, then you have a problem.

Don't know about the "powder" offhand. Has it been run in salt water? Probably some sort of electrolysis corrosion.

Paint peeling at the gasket line is fairly common, especially on a salt water motor.

Burned or discolored paint is a sign of severe overheating, doesn't seem to be a factor here.

 

[so]

Re: white powder around spark plug

thanks for the reply from both of you.

Yes, the previous owner had run it in saltwater and that's the environment I'll using it as well.

Should have mentioned I will (or attempting to) change the gear oil (drain plug is frozen though) and the impeller also. any do's and don'ts during the working process?

I'll need to purchase a compression tester to do compression test. are these testers any good, seems like a good price.
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=92720
how do i ground the plugs, is grounding the electrode onto the engine block good enough?

just go the manual-on-cd for the outboard, but it's rather generic, any suggestion on a better manual?

thanks

s o

 

[Chris1956]

Re: white powder around spark plug

SO, You may use a hand impact driver on the LU plugs. It works very well. when you reinstall them, use new gaskets on the plugs to keep them from corroding up again. Also, use the impact driver to snug them up.

usually, we jump the starter solenoid (positive primary winding to battery side of secondary winding) to make the motor spin for a compression test. Then there is no need to ground the plug wires.

 

[so]

Re: white powder around spark plug

chris1956, lost me here "positive primary winding to battery side of secondary winding", what/where is primary winding and secondary winding? Is primary winding the coil that connects to the spark plug lead? thanks

Stan

 

[F_R]

Re: white powder around spark plug

I think what he is saying is that you can actuate the starter by touching a jumper wire from the positive battery cable to one of the small terminals on the starter solenoid, the one that isn't grounded. That way, you can leave the key switch turned off to avoid sparking or the necessity of grounding the wires. If you are electrically challenged, use the key switch to crank it. But read what I am about to say-

While it may not be necessary to ground the plug wires, I must say that it is highly desireable that you do so. 1, it provides the spark voltage somewhere to go rather than challenging the insulation in the coils, if perchance you have left the key on or there is a fault in the kill circuit. 2, it prevents sparking near the open plug holes which are spewing forth with atomized fuel. A very present and real fire danger. Simply put something up into the boot and contact it with the head or some other major metal part. A 1/4" diameter bolt works well. Or a piece of wire with allegator clips if you want to get real.

Concerning the fire danger, I speak from experience. Nearly set a boat and myself afire one time. The cylinders were flooded and sprayed fire about 10 feet as it came belching out. If I had been in the line of fire, I wouldn't be here to write this.;