Black on transom
#11
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91 454's rochester 4 quadrahejets. Gill silent choice exhaust, premium fuel. Engines were rebuilt before I had them about 60hours ago.. Its more of grey film underneath than black but is definitely exhaust stain. Carbs are being rebuilt as we speak.
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I must add the exhaust pipes themselves arent black with soot. Could the oil pump be pumping to much? I did lost about 1/2 to 3/4 qt of oil after most of the summer of boating, but I dont think thats to off base
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On a Quadrajunk...I mean Quadrajet there are two screws in the base on the front of the carb that are the idle mixture screws. Back in the 70's/80's when I messed with them we would use a baseline of running them all the way in and then backing them out one and a half turns. We would then adjust in or out from there.
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its the same advice i always start with... start with the simple stuff... is the timing correct at idle ? are the temps too cold, have the plugs ever been changed ? all the simple stuff first. has the carb ver been looked at and jetted by someone that actually knows what they are doing and not just watched 3 episodes of hot rod TV ? how about cleaning it virgin and doing a complete trip and never use the silent choice and see if that answers your question ... i suppose it just comes down to how much it bothers you vs how wrong it really is that will determine how much time and effort you spend chasing it... but if it IS legitimately rich, then you are wearing out the motor prematurely for sure...