2007 DF140 stalls in idle

[macedonia]

This was formerly "2007 DF140 stalls when shifted into reverse"

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 jof 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.

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.

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 rpm (spec is 700 +/- 50). The port engines idles at approx. 700 rpm.

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?

Thanks!

[Solarman]

It could be something like dirty map sensor, dirty/ sticking IAC valve, maybe dirty fuel filters? Do you add any fuel additive/ cleaner to your tanks each fill up?

Good luck, post back if you find anything.

[macedonia]

Solarman, thanks for the reply and ideas. We had previously swapped the IAC valves between engines due to a 3-1 code on the starboard engine. The code has cleared and the port engine (which has the previous starboard engine IAC valve) continues to run nominally. And the code has not reappeared on the starboard engine.

I purchased the boat one year ago. The previous owner used ethanol fuel but I switched to ethanol-free marine fuel.

I've been using Sta-bil additive but due to this issue I switched to Sta-bil Performance for the cleaner part. I've run about 30 gallons through the aft tank since (15 gal per engine) Perhaps a different additive/cleaner is better?

We've put about 30 hours on the engines since the last oil change, racor (3213 with plastic bulb) water/fuel separator replacement and low pressure fuel filter replacement. I've got the boat in the water so when I take it out I'll check the low pressure filter. The high pressure filter is due for replacement soon according to the service manual (1000 hours). We're closing in on 900 hours per engine.

Will work on figuring out the map sensor as a potential issue.