reading piston tops 2.5 carb

**redsnapper386** · 04-01-2023, 07:48 PM

guys 1993 2.5 200hp carbs v6 after rebuild and break in im reading spark plugs and piston tops basic question is should they be clean looking or oiley and little black with carbs all adjusted no 2 piston shows up clean all other 5 are oiley and clean carbs are 11/2 turns out is no 2 too lean on that carb not sure here thanks for advice

**David - WI** · 04-01-2023, 08:46 PM

"Clean" is rich... the piston is too cool to burn the oil, so the gas just "washes" it off and no carbon builds up.

But, unless you have 20 hears of doing it daily, you can really only "read" the pistons after running wide-open and killing the ignition as soon as it's safe... not after idling up to the dock or onto the trailer.

**redsnapper386** · 04-01-2023, 08:58 PM

david can you suggest a safe setting on all carbs and then do a high rpm shut off this stuff is all new rebuilt dont want to burn also could the colder water be an issue and running no stats im running a gutted out stat

**David - WI** · 04-01-2023, 09:10 PM

I have no idea what your carbs need. You would have to check the service manual for your year & model. It usually depends on air temperature & elevation.

**David - WI** · 04-01-2023, 09:13 PM

I have no idea what your carbs need, my 2.5 is EFI. You would have to check the service manual for your year & model. It usually depends on air temperature & elevation.