CaptainBob
Well-Known Member
I've installed a Racor Duplex fuel filter before my primary filter, and as a result also additional flexible hoses. At the same time I also installed a priming bulb before the Racor, and had Pirtek replace the final hose (using original compression fitting connectors and copper pipe stubs) which runs between the engine mounted final filters and the injector pump... so in essence I've re-connected all existing connections, and added a load of new ones.
Had some air issues a week ago (air seemed to build up over time when engine not in use) so re-bled, and re-tightened everything, than had flawless running for all of about 4 or 5 starts and short runs.
Yesterday had our first proper run of the season - 3 hours on the engine at good revs - engine nicely up to temperature.
Went to fire it up and no joy. Tried again, hit and miss then stop.
Without opening anything up or bleeding anything I operated the priming bulb - managed a good 4 pumps before it was too hard to pump - and then tried the engine again. It fired up immediately.
2 things I can't figure...
1. Fuel tank level is not far off the same as the high point of the injector pump so I can't work out why air seems to build up over time while the engine is not in use.
2. Why could I, without opening anything up, manage to pump the priming bulb - even with a large air bubble upstream it surely wouldn't allow 4 pumps before offering resistance.
I had a priming bulb on a previous engine (Beta Marine) which had no fuel issues whatsoever and can recall I could pump that one also which surprised me. Am I just filling up the engine lift pump or something perhaps?
Also - the Racor duplex system draws fuel from halfway up itself, so if air was getting in before that, I think it would just create a bubble at the top, under the spin off lid, and not get into the system, so do you think I can assume the problem is downstream of the Racor?
I will remove and re-seat all of my connections one by one and re-bleed. Is it worth using some kind of sealing compound as I do so instead of just rubber-to-copper and copper olives in the compression fittings? I have some Loctite 577 to hand, any good?... but if some got _in_ do I run the risk of it blocking the injectors?
Sorry for the long post. Thanks for any tips you can offer.
Had some air issues a week ago (air seemed to build up over time when engine not in use) so re-bled, and re-tightened everything, than had flawless running for all of about 4 or 5 starts and short runs.
Yesterday had our first proper run of the season - 3 hours on the engine at good revs - engine nicely up to temperature.
Went to fire it up and no joy. Tried again, hit and miss then stop.
Without opening anything up or bleeding anything I operated the priming bulb - managed a good 4 pumps before it was too hard to pump - and then tried the engine again. It fired up immediately.
2 things I can't figure...
1. Fuel tank level is not far off the same as the high point of the injector pump so I can't work out why air seems to build up over time while the engine is not in use.
2. Why could I, without opening anything up, manage to pump the priming bulb - even with a large air bubble upstream it surely wouldn't allow 4 pumps before offering resistance.
I had a priming bulb on a previous engine (Beta Marine) which had no fuel issues whatsoever and can recall I could pump that one also which surprised me. Am I just filling up the engine lift pump or something perhaps?
Also - the Racor duplex system draws fuel from halfway up itself, so if air was getting in before that, I think it would just create a bubble at the top, under the spin off lid, and not get into the system, so do you think I can assume the problem is downstream of the Racor?
I will remove and re-seat all of my connections one by one and re-bleed. Is it worth using some kind of sealing compound as I do so instead of just rubber-to-copper and copper olives in the compression fittings? I have some Loctite 577 to hand, any good?... but if some got _in_ do I run the risk of it blocking the injectors?
Sorry for the long post. Thanks for any tips you can offer.
