Engine Stalling

A

argus1

Member
Apr 12, 2015
196
Apollo Beach, FL
Boat Info
2011 350 Sundancer
Engines
MerCruiser 377 MAG ECT w/Bravo III Drives, Axius
I have a 2011 350 Sundancer with 377 MAG DTS Bravo III Sterndrive, Axius Joystick with about 453 hours on the engines.

The last time I took my boat out, it started fine but the port engine kept turning off. It seem like the rpms would drop until the engine stalled out. Several times I was able to start it again, the last time it stalled I had to wait about 10 minutes before I could start it again. After the last time it stalled out, I held the RPMs below 3000 and was able to back in without the engine stalling (about 45 minutes). Also there a no alarms. I have VesselView Mobile; it shows no faults in the history. I read the posts about the Gen III Cool Fuel Modules, the problems that I am experiencing are similar but my boat is a 2011so it should have the newer CF3? Any ideas?
 
Could be an issue with the throttle body or the throttle position sensor which is an integral piece in the throttle body.

Idle speed is controlled by the electric motor that moves the throttle plate. No more Idle Air Control motors on the DTS system.

With no faults stored, and I assume the ecm is getting good info on coolant temperature, You could swap throttle bodies from one motor to the other and see if the issue moves to the starboard motor.

If the coolant temp sensor is reading a higher that actual temperature, that could cause the stalling on a cold motor.

Also check for carbon build up around the throttle plate. It could just need a good throttle body cleaning.
 
Thanks for the response. I will take a look tomorrow; if it is more than build up that I can clean then I think a trip to the dealer will be in order. I checked; the price of a throttle body is over $700 and I have no idea of what I am doing. The engine does not stall when it is cold. I warm the engine up at the dock before I go out and I have about 15 - 20 minutes in canal where I can only run at low speed - no wake zone before I get to open water; by then both engines are at 150+ degrees. The boat runs fine for a while at 3500-3800 RPM and then suddenly the port engine stalls out.
 
could possibly be a clogged vent for the port fuel tank....next time it happens try removing the filler cap for the port fuel tank....if the problem goes away the vent for that tank is clogged....this will cause the engine to starve for fuel and shut down after running the engine at a higher rpm for a while...

good luck....
cliff
 
argus1 said:
Thanks for the response. I will take a look tomorrow; if it is more than build up that I can clean then I think a trip to the dealer will be in order. I checked; the price of a throttle body is over $700 and I have no idea of what I am doing. The engine does not stall when it is cold. I warm the engine up at the dock before I go out and I have about 15 - 20 minutes in canal where I can only run at low speed - no wake zone before I get to open water; by then both engines are at 150+ degrees. The boat runs fine for a while at 3500-3800 RPM and then suddenly the port engine stalls out.
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Ok. That is slightly different than what I though your were describing in your first post.
 
I just remember that my passenger was sitting on the port side of the boat when it stalled and she said she smelled gasoline. I couldn't smell so I dismissed it. Don't know if this has any bearing or not?
 
Will cost you nothing to put a fuel pressure gauge on it while its happening
 
Service Tech from dealer came out; he thinks that I got water in my fuel and they are recommending that I get the fuel polished and replace the fuel filters.
 
argus1 said:
Service Tech from dealer came out; he thinks that I got water in my fuel and they are recommending that I get the fuel polished and replace the fuel filters.
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did the 'Tech' inspect the contents in the port side fuel/water separator filter to confirm this?....if the contents are poured into a clear container and allowed to sit for a period of time any water in the fuel will separate from the fuel and this separation can be clearly seen through the walls of the container...

if he did not do this he is just 'guessing' at the cause of the problem and spending your money needlessly...

i assume the fuel in the starboard side fuel tank came from the same source as the port side fuel....if so why is it not causing problems with the starboard engine?....

cliff
 
CliffA said:
i assume the fuel in the starboard side fuel tank came from the same source as the port side fuel....if so why is it not causing problems with the starboard engine?....
Click to expand...
My thoughts also. He did pull out the filter in the Cool Fuel Module and found water in the cup. I live in Florida, boat is stored on a lift and due to work travel been sitting on the lift for about six weeks with both tanks around ½ full. If there is water in the tank need figure out how it got there. I am told the need to fuel polish is common here.
 
Is there anything around the boat that may let water into the tank? Preassure washer or lawn sprinkler pointed towards the fuel tank air vent?
 
Ethanol will suck water out of the air. May be cheaper to let the water settle and syphon it off the tank bottom.
You should probably maintain your filters more often. Starboard probably not far behind with same problem.
 
scoflaw said:
Ethanol will suck water out of the air. May be cheaper to let the water settle and syphon it off the tank bottom.
You should probably maintain your filters more often. Starboard probably not far behind with same problem.
Click to expand...

All fuel in brought at well used marina - that only sells ethanol free gas. So, if there is water in the tank I need to figure out where it came from. So, I am headed to the boat now to look around.
 
scoflaw said:
Ethanol will suck water out of the air. May be cheaper to let the water settle and syphon it off the tank bottom.
You should probably maintain your filters more often. Starboard probably not far behind with same problem.
Click to expand...

true but i doubt he is running fuel with ethanol in it....most marinas only sell ethanol free fuel....

cliff
 
Update - I had both fuel in both tanks "polished" and some water was found in both tanks which I am told happens a lot in Florida due to condensation. The dealer told me to add a fuel addictive to deal with the water in the tank and keep the tank full when leave the boat on the lift for weeks at a time when I travel for work; which I did. Also both fuel filters and the round filter at the bottom of the CF3 module were replaced. However the problem did not go away. The port engine is continuing to stall about when running above 3500 rpms. It may run 30 minutes at 3500-4000 RPM before stalling. It will immediately start again and run another 30 minutes at 3500-4000 RPM with no problem. Once running at 1200 RPM it stalled when I powered up to make a turn. It only happens on the port engine. As I said both engines had water in the tank.

I read online in another forum, that a bad alternator could be causing the problem. But I don't want to be guessing and spending money unnecessarily; polishing the fuel was $450 plus a ridiculously high service/diagnosis charge from the dealer. Would an Engine Scan tool be helpful in this situation?
 
scoflaw said:
I'd get a fuel pressure gauge on it while this is happening.
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Not sure how this is going to work; it only stalls at above 3500 RPM which means that I would have to have the hatch open going 25 - 30 miles an hour?
 
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