Mercury Mariner 90HP Three cylinder 1991 s/n0D042985
by Bill Kyle
(Charles City, Iowa)
The engine starts and when idling away from the dock, is reluctant to take the throttle. It hesitates, acts like it is running on one cylinder, and sometimes quits. It starts right back up, and when it takes the throttle, runs flawlessly. Also, at 3000 rpm, the tach quits. It is running perfectly, just no tachometer.