Slow Starting - Air leak?

[bugs]

My volvo 2020 was starting perfectly before I changed my filters but very slow to do so afterwards. It takes a lot of turning over to get it going now. I found that no fuel was coming from the bleed screw on the prefilter/water trap when hand primed. This is the highest point of the system.
I removed and reseated the filter/bowl and rubber rings and immediately got fuel squirting from the bleed screw once primed. A few days later it was the same situation.
The second filter is bleeding fine.
I haven't loosened anything other than the filters and injectors nuts. The engine restarts promptly within an hour or so of starting, the problem seems to take a day to manifest itself.
Any ideas welcome thanks.

 

[Csail]

Think you have answered your own question. Must be air. Just get it running and crack each injector in turn and check filter seals. If they are spin on filters did you smear oil on the seals before fitting?

 

[ThereAndBack]

Sounds like an air leak to me too. The symptoms suggest a leak after the pump so that, when the engine is not running, air gets in and allows the diesel to 'drop back' in the system.

Probably a very small leak if the starting is OK for an hour or so, so you may not see diesel actually coming out of it.

Alan

 

[chamac]

Check the small copper washers on the bleed screws. They can get hardened and brittle from use and slowly let air into the system when its idle.

 

[pappaecho]

I have had the same problem which turned out to be the bleed screw in the water trap/primary filter. Same symptoms as you.

I think that you need to revisit the things which you have changed.
I also think that you need to leave the boat for a couple of days, and then bleed the system, and see if it starts instantly. If so, try the same "leave for 2 days test" and if it does not start, then you need to carefully check each and every thing which you distirubed when you changed the filters