dballardmacon
New member
I have a 1990 90 hp johnson. Ir runs great to 5000 rpm. Bad idle.
I rebuild the carbs, replaced a broken vac hose below the bottom carb. New spark plugs. Idled better but still unacceptably rough. Compressions 135 all cylinders.
Drained the gas, and replaced with new mix gas.
Installed new power pak, coils and plug wires.
I unplugged the gray fast start wire on the power pak. Cranked and checked the WOT timing, it was at 16, specs call for 28 BTDC. I increased the timing to spec. Cranks and idles at 2000 rpm. Verified throttle plates fully closed. Ran the timing back and the idle decreased to 1500, but surges. Hoever, runs smooth on all cylinders, just fast at idle. I do not see any loose vacuum hoses.
What to look for to get the idle back to 900?
I rebuild the carbs, replaced a broken vac hose below the bottom carb. New spark plugs. Idled better but still unacceptably rough. Compressions 135 all cylinders.
Drained the gas, and replaced with new mix gas.
Installed new power pak, coils and plug wires.
I unplugged the gray fast start wire on the power pak. Cranked and checked the WOT timing, it was at 16, specs call for 28 BTDC. I increased the timing to spec. Cranks and idles at 2000 rpm. Verified throttle plates fully closed. Ran the timing back and the idle decreased to 1500, but surges. Hoever, runs smooth on all cylinders, just fast at idle. I do not see any loose vacuum hoses.
What to look for to get the idle back to 900?