2007 DF140 stalls when shifted into reverse

[macedonia]

When returning to the dock after running the boat about two hours, my starboard engine stalled when shifted into reverse. The engines had run great until then but we had not used reverse until docking. Mostly we ran at about 1400 rpm (5-6 knots) and at 4400 rpm (28-31 knots) with absolutely no issue.

The starboard engine had also stalled for one of the dock hands when he had used the boat recently. In fact this had occurred several times for me also. We recently got a 3-1 error code and had the IAC valve inspected and actually swapped between the two engines. The error code did not repeat for either engine so I don't think the IAC valve is the problem.

The folks at the marina think that the idle speed on the starboard engine needs adjusting.

Should we try adjusting the idle speed or consider some other issue?

Thanks!

[Moonlighter]

We had a similar problem a couple of years ago. It was the anti-syphon valve on the fuel tank.

Did you check the primer bulb when the engine stalls? If it was soft/empty:

Simply remove that anti-syphon valve and replace with on open elbow fitting.

As far as I know the idle speed is set and controlled by the ecu with input/support from the IAC valve.

[redlowrey]

When returning to the dock after running the boat about two hours, my starboard engine stalled when shifted into reverse. The engines had run great until then but we had not used reverse until docking. Mostly we ran at about 1400 rpm (5-6 knots) and at 4400 rpm (28-31 knots) with absolutely no issue.

The starboard engine had also stalled for one of the dock hands when he had used the boat recently. In fact this had occurred several times for me also. We recently got a 3-1 error code and had the IAC valve inspected and actually swapped between the two engines. The error code did not repeat for either engine so I don't think the IAC valve is the problem.

The folks at the marina think that the idle speed on the starboard engine needs adjusting.

Should we try adjusting the idle speed or consider some other issue?

Thanks!

...Don't adjust it, it's set at the factory and if you adjust it from the closed throttle switch it will bring the check engine light on. Pull the starboard cover off and check the neutral switch, the contacts are probably still closed in reverse when they should be open, it might need a small adjustment.

[macedonia]

Thank you for the replies.

Here's an update to the stalling issue:

I tested the starboard engine at the dock at idle and shifted the engine into gear (both forward and reverse). Regardless whether the engine was in reverse, forward, or idle it stalled after about 2 1/2 minutes. It seems that this test rules out shifting into reverse as the problem - I'm now thinking that it's just the fact that the engines are at idle speed when docking - sorry for any confusion.

But then the next day I tested the engine again and even after 41 minutes it would not stall (ran mostly at idle but also shifted into and out of gear, no problem). There does appear to be a small amount of sediment in the starboard racor fuel/water separator bulb.

As far as I can recall the starboard engine has not stalled when running over idle speed.

The port engine has never stalled.

This morning when docking, the starboard engine stalled when idling toward the dock. I then restarted the engine and it ran rough. I gave it a little reverse with a bit more rpm and it smoothed out. After docking and shutting the engines down I tried idling the starboard engine again. It stalled after about 2 1/2 minutes. It idles at about 750-775 rpm (spec is 700 +/- 50).

Thoughts?

[Harper]

I have a few questions.
1. You say you swapped the IAC to the other motor and did not get the fault code. Did you leave the valve on that engine, or swap it back? In other words, is the motor stalling now with the IAC that was originally on the port motor?
2. Has the 3-1 code repeated on the starboard motor since the first time?
3. Is swapping out the valve to the other engine the extent of your troubleshooting on that IAC valve? No resistance checks? No checks of the IAC air passage itself?

The attachment is from my DF150/DF175 manual, but the procedure should be very similar for you DF140. Have a look.

[macedonia]

I have a few questions.
1. You say you swapped the IAC to the other motor and did not get the fault code. Did you leave the valve on that engine, or swap it back? In other words, is the motor stalling now with the IAC that was originally on the port motor?

Yes, we swapped the IAC valves so the starboard engine is stalling with the IAC valve that was originally on the port engine. The port engine continues to perform nominally.

2. Has the 3-1 code repeated on the starboard motor since the first time?

No, the 3-1 code has not repeated nor has any other code.

3. Is swapping out the valve to the other engine the extent of your troubleshooting on that IAC valve? No resistance checks? No checks of the IAC air passage itself?

That is correct. That's the extent of the trouble shooting other than running at the shop. No sure about the air passage. Would need to check.

The attachment is from my DF150/DF175 manual, but the procedure should be very similar for you DF140. Have a look.

Thank you for the attachment. I do have the shop manual. I had this work done at a shop. I'm not sure if they followed the procedure from the shop manual.

Here are the other potential issues that other inquiries have uncovered: primer bulb, corroded battery terminal connectors, VST tank issues.

Here's the latest on the water test results:

I tested the starboard engine at the dock at idle and shifted the engine into gear (both forward and reverse). Regardless of whether the engine was in reverse, forward, or idle it stalled after about 2 1/2 minutes. It seems that this test rules out shifting into reverse as the problem (so I started a new thread) - I'm now thinking that it's just the fact that the engines are at idle speed when docking - sorry for any confusion.

But then the next day I tested the engine again and even after 41 minutes the starboard engine would not stall (ran mostly at idle but also shifted into and out of gear, no problem). There does appear to be a small amount of sediment in the starboard racor fuel/water separator bulb though I'm thinking this means that it's working.

As far as I can recall the starboard engine has not stalled when running at more than idle speed.

The port engine has never stalled (even after swapping IAC valves between engines).

My boat has two 60 gallon tanks. It doesn't seem to matter which tank I run off of, the starboard engine still stalls; the port engine does not stall.

Yesterday morning when docking, the starboard engine stalled when idling toward the dock. I then restarted the engine and it ran rough. I gave it a little reverse with a bit more rpm than idle and it smoothed out. After docking and shutting the engines down I tried idling the starboard engine again. It stalled after about 2 1/2 minutes. It idles at about 750 rpm (spec is 700 +/- 50). The port engines idles at approx. 700 rpm (maybe 690).

I tried again a few minutes ago and after 13 minutes, the starboard engine did not stall. I shut the engine down and then restarted and it stalled in about 2 minutes. After restarting several times the starboard engine stalled in approx. 1 to 3 minutes each time.

Any thoughts on where to go from here? Is this a problem that only a Suzuki dealer with a computer could diagnose?