daemon_555
New member
"Engine: Mercruiser 3.0 on Ba
"Engine: Mercruiser 3.0 on Bayliner 175 - 2006
Symptoms:
October 2008:
Idle was rough (sputtering and jumping, would sometimes calmly die). Did not notice the original idle RPM, but increased RPM – idling became “smoother” (but faster). When we were on the water, noticed idle (not in gear) was about 1210 RPM.
For reference, expected idle RPM in gear is 700 according to the manual.
Winter 2008-09:
Starting is hard (too many rotation before starting), even with “priming” the engine (pushing throttle forward into gear and back 3-4 times before starting / cranking the engine). Sometimes need to crank in 2-3 sessions (about 5 seconds each with 10 seconds between cranking) before it starts.
Each time, on the very first acceleration during the day, the boat would pick up RPM and the boat would start accelerating well, but about 15 seconds into acceleration, boat speed would drop dramatically (for the car, this would when the gears shift) for 2-3 seconds (with passengers often being thrown forward a bit). I would reduce the throttle to low and the re-accelerate – the boat picks up RPM and speed and runs solid through the end of the day.
April 2009:
When accelerating away from the boat launch after exiting the no-wake zone, boat lost acceleration for a couple of seconds as above, but then re-accelerated fine. I put the boat under some stress with towing a tube hard.
When the engine was turned to idle (RPM drops to idle = 1210 RPM), then stopped (even when the key is taken out of ignition!), the boat keep running – without the key or ignition – for another 10-12 seconds (sputtering). The boat is in idle, key is out, lanyard switch moved to OFF state, but the engine keeps “running” and jumping. Seems like gas keeps detonating even without a spark. After the engine stops completely, flame arrestor emits a single puff of smoke (smells like oil smoke).
As a separate symptom, during high acceleration, boat seemed to lose power. While the engine’s RPM is very high, the boat seems to lack power – as if it is stuck in the low gear (using a car analogy).
Diagnosed the first symptom as dieseling, reduced RPM back to about 700 idle (measured when not in gear). Was testing with flushing assembly, could not put boat in gear (outside of water) or accelerate hard, but would guess the dieseling problem went away.
Problem:
Now idle is rough again – sputtering and coughing (not too bad, but clearly not a completely smooth idle).
What could be causing this problem?"
"Engine: Mercruiser 3.0 on Bayliner 175 - 2006
Symptoms:
October 2008:
Idle was rough (sputtering and jumping, would sometimes calmly die). Did not notice the original idle RPM, but increased RPM – idling became “smoother” (but faster). When we were on the water, noticed idle (not in gear) was about 1210 RPM.
For reference, expected idle RPM in gear is 700 according to the manual.
Winter 2008-09:
Starting is hard (too many rotation before starting), even with “priming” the engine (pushing throttle forward into gear and back 3-4 times before starting / cranking the engine). Sometimes need to crank in 2-3 sessions (about 5 seconds each with 10 seconds between cranking) before it starts.
Each time, on the very first acceleration during the day, the boat would pick up RPM and the boat would start accelerating well, but about 15 seconds into acceleration, boat speed would drop dramatically (for the car, this would when the gears shift) for 2-3 seconds (with passengers often being thrown forward a bit). I would reduce the throttle to low and the re-accelerate – the boat picks up RPM and speed and runs solid through the end of the day.
April 2009:
When accelerating away from the boat launch after exiting the no-wake zone, boat lost acceleration for a couple of seconds as above, but then re-accelerated fine. I put the boat under some stress with towing a tube hard.
When the engine was turned to idle (RPM drops to idle = 1210 RPM), then stopped (even when the key is taken out of ignition!), the boat keep running – without the key or ignition – for another 10-12 seconds (sputtering). The boat is in idle, key is out, lanyard switch moved to OFF state, but the engine keeps “running” and jumping. Seems like gas keeps detonating even without a spark. After the engine stops completely, flame arrestor emits a single puff of smoke (smells like oil smoke).
As a separate symptom, during high acceleration, boat seemed to lose power. While the engine’s RPM is very high, the boat seems to lack power – as if it is stuck in the low gear (using a car analogy).
Diagnosed the first symptom as dieseling, reduced RPM back to about 700 idle (measured when not in gear). Was testing with flushing assembly, could not put boat in gear (outside of water) or accelerate hard, but would guess the dieseling problem went away.
Problem:
Now idle is rough again – sputtering and coughing (not too bad, but clearly not a completely smooth idle).
What could be causing this problem?"