VP AQD40 turbo boost query

[symondo]

thats a pretty small filter for an engine. I have something similar to that supplying just a generator. Well worth upgrading as per VP when possible. That style of filter isn't very good at separating water out either. Given the size of it and your empty tanks, old fuel, age etc, although they have recently been replaced it may well already be bunged up.

will investigate as per suggestions on upgrading the filters. We just assumed they were fit for purpose due to already being fitted.

will also look at this pre filters and basically explore the system a little bit more to understand it better.

 

[symondo]

Didn't get a chance to check the filters today however, we did fire up both engines and let them warm up.

At this point we left them in neutral and tried revving them to see if we has the same boost issue while moored, both engines ran upto 3400rpm with no problems, no vibration or odd noises and also on bringing the revs down you could hear the turbo spooling down on both engines.

 

[Divemaster1]

Remember that the load on a diesel engine, and thus fuel draw, in neutral is virtually nothing compared to when she is under load (in gear and propeller driving the tonnes of boat forward displacing water).... so your problem could easily be related to fuel restriction... I'd check the filters again... easy that an empty tank, refilled again will have caused a lot of crud to be stirred up and drawn in to the filter... clogging it.

 

[symondo]

Remember that the load on a diesel engine, and thus fuel draw, in neutral is virtually nothing compared to when she is under load (in gear and propeller driving the tonnes of boat forward displacing water).... so your problem could easily be related to fuel restriction... I'd check the filters again... easy that an empty tank, refilled again will have caused a lot of crud to be stirred up and drawn in to the filter... clogging it.

Yeah i thought that would be the case. I figured to try this in neutral while not moving would eliminate the throttle cable positioning, any issues with the engine as it would replicate the problem or flag up something else. However all seemed ok on those departments so i also reckon its down to fuel supply.

 

[Divemaster1]

Yeah i thought that would be the case. I figured to try this in neutral while not moving would eliminate the throttle cable positioning...........

Sorry it won't eliminate the cable positioning .... in neutral, you'd easily obtain full RPM with less than half the throttle movement.... Only way you can eliminate cable is to push throttles all way forward (not on running engine) and go down to engine to see if the leaver on the fuel pump can move further ... basically dis-connecting the cable and see if the cable actually can push the pump to WOT....

 

[symondo]

Sorry it won't eliminate the cable positioning .... in neutral, you'd easily obtain full RPM with less than half the throttle movement.... Only way you can eliminate cable is to push throttles all way forward (not on running engine) and go down to engine to see if the leaver on the fuel pump can move further ... basically dis-connecting the cable and see if the cable actually can push the pump to WOT....

hmmm this boat malarky definately is a never ending chapter of little things to look for lol

Ok, i shall take note for my next visit