Spark plugs 115TXRY

[aginsa]

I'm still tracking down my rough idle on my six year old motor. This motor was purchased used with little hours and NO maitenance. Anyways I changed the plugs last night and Oboy were they in bad shape. Completly black and what looked like rust. The owners manuel says I should use a ten second spray of YamaLube into each cylinder. Any suggestions?

[boats.net]

Yes spraying with fogging oil couldn't hurt. You can add a 50:1 oil mixture to gas tank until all checks out. Have you done a compression test?

[aginsa]

I have not checked the compression yet (waiting on the tester). The cylinder head gaskets look to be in poor condition. The motor runs great at speed, just stalls after awhile at idle.

I guess I've got issues because I'm enjoying working on the motor. Anyways I've replaced the fuel filter (both water seperator and inline micro filter). Idle speed was also adjusted to 700-800rpm.

Could the carberator be causing this problem, or is compression a more likely possibility.

[slim]

if its hitting on all 4 cyl's, you shouldnt have to clean the carbs. i have found that on a 115, a idle speed of 900-1000 in neutral sometimes helps. but what i would do is richen the carbs up about a 1/4-1/3 turn on each. is it coughing or popping before it dies? if so, this should take care of it.

[slim]

you also might try resyncing the carbs.