Difficulty bleeding CAV DPA fuel injection pump

[sanibel sailor]

Engine is a Westerbeke W30, AKA 4-91. Was running fine, but had an annoying fuel leak from the pump.
I just removed the fuel injection pump to reseal it, replaced the O ring between the housings as well as the other gaskets. I have reinstalled it and am having trouble getting the pump to bleed. I have an electric pump which I can run independent of the ignition switch. I hear fuel return to the tank when the pump runs, I get fuel dripping from the bleeder on the rear (tranny side) housing as well as from the pressure switch bleeder on the front. However, when I crank it, I have no fuel coming out the top bleeder on the anti-stall device. I even removed the entire anti-stall (9/16" hex) to see if that would do it, but I get no fuel there or out the lines to the injectors, which I had completely disconnected.

Fuel hoses from filter are correctly connected, kill cable in correct position, throttle at half. Oriuentation of pump to crankcase is correct, but even if wrong, that should not prevent it from bleeding.

After fooling with it for a couple of hours in midday heat, I decided to give it a rest to adjust our respective attitudes. I am recharging the batteries overnight and plan another try tomorrow.

Anything I may not be thinking of? Possibly a stuck plunger? I have considered that I may have damaged the sensitive innards but I was quite careful and clean and the thing only assembles one way with everything keyed together.

[model 10]

This is why I paid the big bucks to have it done by a shop. Good luck.

[sanibel sailor]

Thanks for the response. I am emboldened by the fact I have a spare sitting on the shelf. Although I can afford it when required, I prefer skill building rather than check writing.

[Cuttyhunk]

Did that once, on a 1979 Westerbeke 30. Annoying little leak. Put it all back together oh so carefully. Unfortunately, not carefully enough. Fired it up, the diesel ran away and kept going even after we had closed the fuel,shut off. Finally it died just as we were jumping into the dinghy, as we were sure it was going to blow up any second.

We were lucky; it just blew the head gasket and (as we later discovered) weakened some freeze plugs and a temp sensor. We had plenty go time to take it to a shop and get it fixed while we waited for the new head gasket. Count yourself lucky it won't start...it could have been worse!


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[sanibel sailor]

Pulled the pump and brought it home for a closer look. Took it all apart and the plungers were not stuck, slide easily, sweetly tapping gently back and forth when rotated. Upon reassembly, I discovered the problem.

ENVELOPE PLEASE! (drumroll).....

survey says- stuck kill lever plunger. The plunger is forced down by the lever, then recoils by spring action (and perhaps fuel pressure in operation). Seemed to go together fine, but I pulled the anti-stall device off and looked inside, confirming it was not rising when the lever was placed in run. A squirt of WD40 on the plunger and in the hole (more to clean any microscopic grit than for lubrication), worked it back and forth a few times and now she's all better. Reassembled to engine, it bled promptly and fired right up. Did not even run away. Now we will have to wait to see if I actually fixed the leak or not, but total cost was $17 for the seal kit, probably a couple of bucks for paper towels/spray paint/gas to drive to the boat, etc. Remainder of those big bucks will go into the cruising kitty.

[model 10]

Way to go

[HappyMdRSailor]

I could have saved ya the anxiety, but discovering it yourself made ya a DPA guru...

Other clue for somebody in the future researching a problem... sticky stop mech not overcoming the spring tension...

Congrats man!