still_bill
Contributing Member
Hello;
Been a while since I've been on this forum.
I have a 1990 Evinrude 120HP looper. It has been very well maintained, but has a lot of hours. Fresh water exclusively in last 12 years.
It was running great when parked 2 weeks ago, right after it was tuned-up with new plugs, water-pump, fuel lines, bulb and filter. Went to run it yesterday and it started right up and idled fine. However, upon acceleration it starts surging and shaking, and makes no power. Almost like ignition is cutting on and off. It will do the same thing in neutral using the warm-up lever, or even just moving the carb linkage.
Has spark at all 4 cylinders (at rest). Compression seems OK (thumb test, as my gauge just broke). Anyhow, I don't think it is a mechanical issue since it ran fine when parked 2 weeks ago.
Any thoughts about what it may be? Anyone ever hear of a power-pack going bad like this? My experience is that they are usually all-or-nothing.
Also - VRO was removed many years ago. Running on premix. Pumping bulb while running has no effect on problem.
The "surge" is almost violent, with a frequency of about 1-second. Revving up and down.
Been a while since I've been on this forum.
I have a 1990 Evinrude 120HP looper. It has been very well maintained, but has a lot of hours. Fresh water exclusively in last 12 years.
It was running great when parked 2 weeks ago, right after it was tuned-up with new plugs, water-pump, fuel lines, bulb and filter. Went to run it yesterday and it started right up and idled fine. However, upon acceleration it starts surging and shaking, and makes no power. Almost like ignition is cutting on and off. It will do the same thing in neutral using the warm-up lever, or even just moving the carb linkage.
Has spark at all 4 cylinders (at rest). Compression seems OK (thumb test, as my gauge just broke). Anyhow, I don't think it is a mechanical issue since it ran fine when parked 2 weeks ago.
Any thoughts about what it may be? Anyone ever hear of a power-pack going bad like this? My experience is that they are usually all-or-nothing.
Also - VRO was removed many years ago. Running on premix. Pumping bulb while running has no effect on problem.
The "surge" is almost violent, with a frequency of about 1-second. Revving up and down.