Scanos
09-01-2006, 04:57 PM
This is my ongoing saga....1990 Mariner Mag II 150. I have an ongoing idle issue that has improved but is still a problem. I have rebuilt the carbs, adjusted floats, new needles seats etc. It runs well on top end and mid-range...it was really rough until I noticed a couple of pin holes in a couple of fuel lines between top carb and middle carb basically just sweating a little fuel...replaced all the fuel lines now idles better but still not right. Most of the roughness is gone but it seems to not maintain a steady rpm. I have an inductive Tach and all cylinders seem to fluctuate 100 RPM or so up and down all are the same no difference between them. Wondering maybe fuel pump diaphram? Also I ran today it wet fouled plug on cylinder #1 the rest were fine....may have an ignition issue with this plug as well...looks good at idle with inductive tach but maybe missfiring at highspeed? Would fuel pump cause RPM fluctuation like that? Is there anything else that could cause that? I have tried test fuel tank with no difference. Is there anything besides ignition that could cause #1 to wetfoul and not #2? Thanks in advance