How to bleed air from a 2QM15 Bosch Injector pump

"I've got fuel getting as

"I've got fuel getting as far as the injector pump, but nothing coming out. This after dirty fuel ran into the system. I've cleaned everything up (tank, diesel, filter-separator, lines -- the works) and installed new filters.

Peter Compton's book suggests I "follow the service manual's instructions" on bleeding air from the pump. But neither the Yanmar service manual, nor a Clymer book (admittedly, covering the 2QM20, but not the 15, exactly) give instructions, and I don't think the pump (a "Bosch integral type") has any bleed screws.

So, before I take it apart and clean it out, I'd like to make sure I'm not missing a less invasive fix. Any help will be appreciated!"

"Ooops! Not "Clymer",

"Ooops! Not "Clymer", but "Chilton" ("Seloc"). Regardless -- it doesn't specifically cover the 2QM15, but does the 2QM20, which has a (seemingly) identical injector pump."

test

test

"Bleed the system and final bl

"Bleed the system and final bleed will be at the FI pump, you may have to get 2 12 mm packings when you loosen the banjo bolt at the pump. Once done it should self bleed to the injectors. Some install an outboard fuel bulb to PUSH fuel before the filters all the way to the FI pump. Good luck with it it"

"Thanks for that. Didn't

"Thanks for that. Didn't work, so now I've got the pump (carefully) disassembled for cleaning. (I've crossed the line -- there's no turning back!)

Re: outboard fuel bulb -- see my other post in "General Diesel Questions". It's a great idea to push fuel -- unfortunately, it had a side-effect in stirring up and pushing a bunch of watery, dirty sludge, too. So, the lesson I learned from this: if you take steps to increase the flow of fuel in an old system, clean everything out thoroughly before you start pumping!"

"Well, the injector pump clean

"Well, the injector pump clean-out and reassembly went very well. First time thru, the rack wouldn't move with only gravitational force when the pump was tipped on its side. Turns out one of the pump's piston/collar assemblies was (still?) binding. I cleaned 'em again, dried 'em off, and "lapped" them by moving the piston in & out repeatedly past the point of binding. That freed it up and then the pump behaved correctly when reassembled. Got the engine started again, so the whole fuel system clean-out is finished. (Whew!)

However, the engine is still starting reluctantly, so a compression test is next.

BTW, those few of you who may have the Yanmar service manual for your 2QM15 engine (and maybe others of similar vintage): The illustrations and text for the injector pump disassembly and reassembly instructions are obviously mismatched. Pay little attention to the pictures, follow the text, and you'll do fine.

(And, re my original question: There is no specific bleed screw -- simply loosen the nuts holding the injector supply lines at the pump until fuel starts spurting out without obvious bubbles, then tighten 'em down and move on the injectors.)"