85 'Rude 90hp...First run after rebuild

[Reggie08]

Took the motor out to the lake this afternoon and ran it for about 40 minutes. No glaring problems that I could tell. Definitely need to get the timing and idle set however as well as new plug wires (pulled two of em out of the boots trying to put cowling on). I did have one question however, pulled the plugs once we got the boat back on the trailer. First one (#2 cylinder) looked good. Oily with sort of a brass/gold look to it. Seemed fine to me. The other three however had some sort of crud on them. Wiped some of it off the plug and rubbed it between my fingers thinking (and hoping it wasn't) it was aluminum Didn't appear or feel like it was metal.

The stuff I'm seeing is black in color and left the piston heads speckled. Makes me think it could be carbon. But there was very little carbon to start with when I did the rebuild (new pistons, rings, rod bearings, etc) I also didn't run the motor at WOT since the manual said for the 1st hour of break-in, not to take it over 3000rpms or approx. half throttle. Don't have the tach installed yet but I kept it at no more than half throttle. Could this stuff be carbon from not running it WOT?

Motor didn't feel hot. I could keep my hand on the top of the engine for several seconds. Water stream was strong (checked temp of water while motoring around and it was cool). and I used fresh gas and Evinrude 2-cycle oil. All around, it seemed like it ran good. Just a little concerned about this stuff on the plugs/piston heads

 

[Benny1963]

Re: 85 'Rude 90hp...First run after rebuild

reggie did you set your timeing pointer before you timed it .
the crud could be crap from motor .clen your plugs reverify you wot timeing
the gray in color could be from water intrusion exhaust gasket .poss.
did you check your heads for flatness strait edge with feeler gauge .
when i put mine back i had a couple of cyls that grayed up had warped head
had them cut fixed prob ,if ya have to pm faztbullet he can help with these probs may take him a while to respond he working a lot
pm me if ya need and i will help ya .

 

[Reggie08]

Re: 85 'Rude 90hp...First run after rebuild

I didn't notice any gray coloring, just the black specks. I also had the heads machined to make sure they were flat and squared off then torqued the bolts to spec's. I'll try to take a picture of it tomorrow and post it. All 4 plugs were oily so it didn't seem like there was any lack of fuel/oil going thru.