Hi all! Someone recently gave me a 20' pontoon boat with a 60hp Mercury Outboard, a 2001. The engine sat for about 6-9 months over the winter prior to my being able to use it. I had it checked out by a Mercury service center and they said everything looked good, and the first few times out it seemed to run fine.
Last time I was out, we were cruising along for a while when the RPM's dropped from about 5000 to 3700 without touching the throttle. At the lower RPM's, the engine still sounded ok, just slower. Once I let off the throttle, the engine died, it wouldn't slow down, just died. It still starts fine, and idles well to about 1700 RPMs, then it shutters and dies. If I try to accelerate hard, it will get back up to 3700 RPMs, but it won't stay in the 1800-3600 RPM range at all. After the problem started, while trying to get off the lake, the engine did pop back up to 5000 RPM's a couple times but fell back to 3700 fairly quickly. Any time I let off the throttle at all, it dies almost immediately after a little shutter. When it dies, it usually emits a single short beep.
Spark plug #4 looked like it might have a little oil on it, and the oil level is right at the high mark on the dipstick. I'm about to change all the plugs and see if that has any impact, but I was hoping someone has seen a similar problem and can offer some advice.
Any ideas?
Last time I was out, we were cruising along for a while when the RPM's dropped from about 5000 to 3700 without touching the throttle. At the lower RPM's, the engine still sounded ok, just slower. Once I let off the throttle, the engine died, it wouldn't slow down, just died. It still starts fine, and idles well to about 1700 RPMs, then it shutters and dies. If I try to accelerate hard, it will get back up to 3700 RPMs, but it won't stay in the 1800-3600 RPM range at all. After the problem started, while trying to get off the lake, the engine did pop back up to 5000 RPM's a couple times but fell back to 3700 fairly quickly. Any time I let off the throttle at all, it dies almost immediately after a little shutter. When it dies, it usually emits a single short beep.
Spark plug #4 looked like it might have a little oil on it, and the oil level is right at the high mark on the dipstick. I'm about to change all the plugs and see if that has any impact, but I was hoping someone has seen a similar problem and can offer some advice.
Any ideas?
