Found an incredible Prevost auction.

[mwilson]

Sno, what year is the engine in that conversion? Is it mechanical or DDEC?

Yes, good question. I made the assumption that it was not DDEC which may have been a mistake.There were some that were.

 

[Wayne M.]

In my marine years, I took care of a 90's 8V92 that was DDEC. it cooked a cam in a couple hundred hours.

 

[mwilson]

Here is a DDEC 6V-92 running with Valve Cover off. Non electronic versions have a rod where the solenoids are in the video.

https://www.youtube.com/watch?v=Zf7UG25i-EM

 

[mwilson]

Outside rockers are all exhaust. Center rocker is for the injector.

 

[mwilson]

The components of the mechanical fuel system. Very simple.

 

[mwilson]

Notice above that the rack has one screw and spring per injector. That is to prevent runaways as a result of a stuck injector. The spring allowed the rest of the rack to move in spite of a bound up injector.

The older style racks had two screws and no spring. If one injector stuck wide open all of the other injectors did as well. Got hairy at times.

 

[Wayne M.]

Yes. That's a DDEC. See the wires going to the injectors?
Heres a guy playing with his rack. Not following the book. I'm no expert with this, but it takes a brave man to start it afterwards.

 

[mwilson]

Yup, I've set many of those up. Injector "C" will bounce back up ever so slightly when properly set.

 

[SnoKing]

It is a mechanical I believe. I suggested an electric fuel pressure gauge past the fuel pump(s) to see if it was loosing fuel pressure. One the hoses in the engine compartment looked real old and suspect of problems internally. I recall that fuel for the tank which is may forward was carried in a pipe back to the "engine room". Fuel tank is big and old, who knows what might be in it. SNOKING

 

[Wayne M.]

Nothing easy about that diagnosis. Lots of hard yucky work.

 

[mwilson]

I'm hoping for his sake that it is a lazy fuel shut down unit. the alternative is indeed messy and smelly.....:{