offthepath
New member
I have an 06 Crownline 240EX with a 350 Mag mpi bravo 3 (OW375597). I purchased the boat last fall and we have been having a nagging hard start issue.
The boat starts right up on the first start of the day, but after that the boat needs 1/4 throttle to start. It does not seem to correlate to engine temp, it can be 1-2 min of run time or hours and it will not (or very seldom) start without 1/4 throttle. If you don't give it 1/4 throttle, it generally acts like it is trying to start but will not catch. Once it starts there are no hiccups, rough idle, or any other problems while the engine is running.
Here's the kicker, it only does it on the water. When running on the hose I cannot recreate the problem. 1-2 seconds of cranking and it starts every time. Hot, cold, whatever, it will start all the time.
So far this is what I have done over the past year:
-New IAC and muffler
-New spark plugs
-New cap and rotor
-New fuel filters
-Tested coolant temp sensor
-Tested fuel pressure. All normal values. When turned off, the gauge bleeds off about 1psi every minute. I'm assuming this is fine?
-New 950cca battery and new 650cca deep cycle backup battery. These batteries have recently been load tested also.
-New battery cables
-New starter
-No decreeable voltage drop between cables, starter, etc. Shows around 11.6-11.7 while cranking.
From this question on another forum, I was told the engine needed to turn 300rpm to start. It appears the dash gauge is just shy of 300 RPM. Based on this, I started looking at the starting system which lead me to replacing the battery cables. After that, the boat started fine for 2 short trips, but now the same issue is occurring. I have pulled the cables back off, double checked and cleaned grounds (fresh water and no corrosion) and no change, so I went ahead and replaced the started, but still nothing.
At this point, I am guessing the cranking speed is the issue, but that is all assuming the dash tach is accurate. I have noticed that on the hose when you turn the key and it begins cranking the RPMs read 0 until it starts. When the starting issues occur, the RPM show just under 300 as the engine is cranking. Not sure if this is related.
Any help would be appreciated, I'm at my wits end with this boat.
The boat starts right up on the first start of the day, but after that the boat needs 1/4 throttle to start. It does not seem to correlate to engine temp, it can be 1-2 min of run time or hours and it will not (or very seldom) start without 1/4 throttle. If you don't give it 1/4 throttle, it generally acts like it is trying to start but will not catch. Once it starts there are no hiccups, rough idle, or any other problems while the engine is running.
Here's the kicker, it only does it on the water. When running on the hose I cannot recreate the problem. 1-2 seconds of cranking and it starts every time. Hot, cold, whatever, it will start all the time.
So far this is what I have done over the past year:
-New IAC and muffler
-New spark plugs
-New cap and rotor
-New fuel filters
-Tested coolant temp sensor
-Tested fuel pressure. All normal values. When turned off, the gauge bleeds off about 1psi every minute. I'm assuming this is fine?
-New 950cca battery and new 650cca deep cycle backup battery. These batteries have recently been load tested also.
-New battery cables
-New starter
-No decreeable voltage drop between cables, starter, etc. Shows around 11.6-11.7 while cranking.
From this question on another forum, I was told the engine needed to turn 300rpm to start. It appears the dash gauge is just shy of 300 RPM. Based on this, I started looking at the starting system which lead me to replacing the battery cables. After that, the boat started fine for 2 short trips, but now the same issue is occurring. I have pulled the cables back off, double checked and cleaned grounds (fresh water and no corrosion) and no change, so I went ahead and replaced the started, but still nothing.
At this point, I am guessing the cranking speed is the issue, but that is all assuming the dash tach is accurate. I have noticed that on the hose when you turn the key and it begins cranking the RPMs read 0 until it starts. When the starting issues occur, the RPM show just under 300 as the engine is cranking. Not sure if this is related.
Any help would be appreciated, I'm at my wits end with this boat.