Cummins 6BT Stalled and wouldn't restart when hot

[Keith Bachand]

I purchased a 1979 Trojan F26 that was fitted with an older Cummins 6BT. After many blown trailer tires (trailer is in bad shape) and a failed launch attempt (prop stuff box was leaking), I finally got it in the water to place her in a slip.

Motor was pumping good seawater, was a little slow to start cold, but it fired up. After leaving the dock and getting her up to 2000 RPMS there was some smoke coming from the exhaust manifold area (hard to tell exactly where since it was super crowded and I just needed to make it to the slip). The turbo was NOT spooling…And some black smoke (not super bad but it was there) was coming from the exhaust. Temp got to 130 degrees on the gauge.

I brought her back to 1500 RPMs and smoke slowed down from the manifold but still no whistle at all from the turbo and just didn’t sound like a normal Cummins. I brought down to almost idle and it stalled and would not restart (I was halfway to the boat slip). Cranked slow and acted like batteries were down but the gauge said 14 while the engine was running and after it cut off it was at 12. I, of course, made sure it was in neutral and all before restarting.

Details:
-Max RPM: 2000 (No turbo spool at all) **I could have gotten to higher RPM but was afraid when I saw the smoke from the motor from the manifold area**
-Max Temp: 130 degrees
-Exhaust smoke: Some black smoke but not pouring out just a few puffs here and there.
-Oil PSI was around 30 when underway (was 40 PSI when cold)
-Issue: Stalled and would not restart when hot. Slow Cranking with batteries at 12V (gauge showed). Was 14 while under power.

Any leads on what the issue could be? I have not attempted to restart since getting into the slip since I don’t want to cause any additional damage.

Of course, without an hour meter, my mind jumps to bad compression and needing a rebuild which I just don’t have the budget for.

Here’s a video of the motor idling on the trailer prior to launching. https://www.youtube.com/watch?v=__QkpS_nRkA

Topic

[Tony Athens]

urlLet’s see—. Zero coolant expansion tank. You expect this to work?? Next. Remove the exhaust mixer. I want to SEE inside your turbo.

Tony

[Bill Stenger]

Weak starter and or batteries? Hook up some jumper cables and start with basic no start testing. The manifold doesn’t look burned like it was hot or anything. Im not sure where this smoke is coming from. Maybe residual oil being burnt off? Or very possible that the turbo gasket is bad. And that was exhaust soot blowing out there? If that is the case coolant could have leaked from turbo gasket down into the cylinders. very unlikely while running though. Highly doubt an engine that was running good and sounded good at idle all of a sudden has such low compression it wouldn’t run. Low compression would make it easier to crank over then normal not more difficult.

You need to try and restart the engine and go from there. If you verify it will not crank over with good batteries and starter. Then it may have ingested water or coolant. And may be hydro locked. Which would require pulling the injectors and blowing or sucking out the water of the cylinders.

[Kevin Carlson]

The exhaust water injection that close to the turbo without a good rise seems suspect. Probably killed the turbo. This wouldn’t necessarily cause the hard start though.

[Keith Bachand]

Bump for good luck!

[Author]

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