6.2 Stalling

[Steve Craig]

Hi all,
I have a 6.2 Mercruiser with DTS & a B3 drive in an '07 260 Sundeck. Raw water cooling with new manifolds & risers last year. We use a non-ethanol fuel. Lots of oil in the crankcase. Engine running just fine, however, occasionally upon start-up it will run 5-10 seconds & cut out. I hear the alarm beep once as it quits. Starts easily initially & then restarts very easily.
Once restarted it runs fine. Stalled once coming into the berth but restarted again quickly.
Mechanic unsure at this point & neither of us are fans of simply throwing parts at it.
I'm thinking a fuel delivery issue but it's a guess.
Is there a plug-in port on the engine we could check for activity on alarms & shutdowns ? Perhaps something similar to a car engine ?
Are there absolute conditions the ECM will see & shut it down ?

Thank You for any help you can offer.

Steve C

 

[Espos4]

With DTS, there is no IAC valve, which is a common cause for stalling in engines so equipped.

Idle speed in our DTS engines is controlled by the throttle motor opening the throttle to let a small amount of air to enter.

An easy thing for you to check is the throttle plate itself. Carbon built up in the throttle body and on the plate will case stalling. Clean it up with carburetor cleaner, let it sit 30 minutes or so for the cleaner to evaporate, and see if that helps.

 

[Steve Craig]

Appreciate the reply. Think I'll head down to the berth & try it tonight.
I'll let you know what I find.

Thank You,
Steve C

 

[Steve Craig]

Just back from cleaning the throttle body as you suggested. There was a small ridge of carbon around the bore where the blade met the body. Got almost all of it with a can of throttle body cleaner, a tooth brush & some rags.
Started the engine 3 times & let it run a few minutes. All seems good tonight. I'll keep track of it & post again in about a week. Hopefully this ends it. Couple pics of before/after but you can't see the carbon ridge on the before.

Thyanks again

 

[Steve Craig]

Problem still with me.
Out today with the family. Stalled once just after a cold start but restarted easily & ran well on the way out. We were at anchor for a couple hours. Started easily & stalled after a minute. Restarted & ran well on the way home.

 

[Espos4]

Had your cool fuel module ever been replaced?

 

[paulswagelock]

Since it is so repeatable, troubleshooting is easier.
Put a gauge on the fuel rail and watch it when it stalls.

 

[Steve Craig]

I'll pick up a gauge & check the fuel rail as suggested.
Stalling is pretty random. We had new SeaDek flooring installed Friday & I was down Saturday AM having a look.
Stayed for a couple hours talking with slip neighbours.
Started it 3- 4 times over the 2 hours & it was fine.

Fuel rail hasn't been changed to my knowledge.
I'll report back.

 

[Steve Craig]

Update.
COVID hit me like a ton of bricks 2 weeks ago. Vaccinations & booster kept me out of the hospital I believe. Only time in my life I've ever felt worse is about 20 years ago when I had a bad case of blood poisoning from a cut on my hand.
Just prior I had the marina mechanic change the filters/elements on the fuel module. He was able to do it right at our berth. They hadn't been done in a long time by the look of them. This just on a hunch & I didn't want to pull the boat to trailer it to my regular mechanic.
Felt better late this week & was able to salvage a few days of a scheduled vacation. Ran the boat on 3-4 outings taking advantage of the good weather. Started & ran like a champ, no stalling at all.
I have a new cap & rotor to put on & a noisy idler to replace this week.
Appears to be resolved.

Thanks everyone.