CliffA
Well-Known Member
- Dec 29, 2009
- 4,712
- Boat Info
- 2001 Sea Ray 340DA
Name: 'Happy Place'
4.5kW West. Generator
Purchased Nov. 2014
Fresh Water Use
- Engines
- Twin Merc. 6.2L (MPI)
640 hp (Total)
Raw Water Cooled
V-Drive Transmissions
long post but I want to give as much detail as possible.....
I went to my boat yesterday and decided to run my engines for a while...for information it had been several weeks since the last time I ran the engines and we have had sustained and extreme cold temps for this area this winter but my ER temp never got below 40*...
both engines stared fine without issues and settled into an idle speed around 650 rpms.....
after a few mins at idle speed both engines stalled at almost the same time....i looked at the temp gauges and they both had reached normal operating temp of 170*F.....it started me thinking that reaching normal operating temp triggered something in the ECM and caused the engines to shut down....
both engines started back up immediately and settled down once again into a smooth idle of 650 rpms and both were at normal operating temp of 170*....
when I tied to give the throttle a quick advance bringing the rpms up to around 2,000 and quickly moving the throttle back to idle position both engines would start to surge or 'hunt' for the correct idle by speeding up and slowing down the rpms and after a few seconds of this the engine would stall....both engines exhibited the same behavior.....
again they both stated back up immediately and would settle into a smooth idle...but every time I tried a quick increase in rpms they both would surge a few seconds and stall....if I did not advance the throttle the engines would idle fine....I could also advance the throttle slowly and both engines would accelerate as expected but once I brought the throttle back to idle position the engines would surge and stall...
this went on for approximately 15 - 20 mins until I finally decided to take the boat over to a nearby pump out station for a head tank pump out...I traveled at idle speed most of the way since the pump out station is very close...I let the engines idle while I pumped out the head tank without issue....
on the way back to my slip I blipped the throttle a few times and both engines settled down to a smooth idle without surging or hunting and no stalling....obviously by this time the engines had thoroughly warmed since they had been running for around 45 mins.....
my first thought is there is a problem with the IAC valve but chances of the IAC failing on both engines at the same time is very remote....
any suggestions as to the cause of the idle surging and stalling when the throttle is opened quickly and brought back to idle position?
thanks...
cliff
I went to my boat yesterday and decided to run my engines for a while...for information it had been several weeks since the last time I ran the engines and we have had sustained and extreme cold temps for this area this winter but my ER temp never got below 40*...
both engines stared fine without issues and settled into an idle speed around 650 rpms.....
after a few mins at idle speed both engines stalled at almost the same time....i looked at the temp gauges and they both had reached normal operating temp of 170*F.....it started me thinking that reaching normal operating temp triggered something in the ECM and caused the engines to shut down....
both engines started back up immediately and settled down once again into a smooth idle of 650 rpms and both were at normal operating temp of 170*....
when I tied to give the throttle a quick advance bringing the rpms up to around 2,000 and quickly moving the throttle back to idle position both engines would start to surge or 'hunt' for the correct idle by speeding up and slowing down the rpms and after a few seconds of this the engine would stall....both engines exhibited the same behavior.....
again they both stated back up immediately and would settle into a smooth idle...but every time I tried a quick increase in rpms they both would surge a few seconds and stall....if I did not advance the throttle the engines would idle fine....I could also advance the throttle slowly and both engines would accelerate as expected but once I brought the throttle back to idle position the engines would surge and stall...
this went on for approximately 15 - 20 mins until I finally decided to take the boat over to a nearby pump out station for a head tank pump out...I traveled at idle speed most of the way since the pump out station is very close...I let the engines idle while I pumped out the head tank without issue....
on the way back to my slip I blipped the throttle a few times and both engines settled down to a smooth idle without surging or hunting and no stalling....obviously by this time the engines had thoroughly warmed since they had been running for around 45 mins.....
my first thought is there is a problem with the IAC valve but chances of the IAC failing on both engines at the same time is very remote....
any suggestions as to the cause of the idle surging and stalling when the throttle is opened quickly and brought back to idle position?
thanks...
cliff