VP 170HP 3ltr 6cyl .... takes time to start and keep running.

[Refueler]

As you see with airbox removed - massive carburettors .....

That is the problem I think.

When boat has stood a while ... the carbs appear to drain ... so when I go to start .. I need to first crank on full throttle - she fires ... pull throttle back to about 5 - 10% and turn key - she fires again .. starts but peters out. I basically repeat this a number of times ... finally getting her to rev .. but need to keep revs up over 1200 for a while ... before she will idle.

My impression is those big carbs need time to be 'pumped' up by the lift pump ... those early starts are purely fuel collecting up - firing - then not enough to sustain running till carbs are full and engine warms a touch.

Suggestions please ? Inline priming pump ?

 

[spannerman]

I had the same problem with my Mercruiser V8, so I fitted an outboard motor primer bulb in the fuel line, a few pumps and I can hear the big twin float chambers filling up, she then starts at the first turn of the key. Saves wear and tear on the battery and starter.
If I recall there is no choke on your carbs, check that fuel squirts out of the curved nozzle visible in your pics, this is the accelerator pump and a few full pumps on the throttle squirts raw fuel into the carb this helps when starting from cold.

 

[Refueler]

I thought of the primer bulb ... what turned me away from it - the cockpit floor is a double affair, inner engine box insulated and real pain to open up to the engine.

So as I understand it ... if I give the throttle lever a number of full lever movements - I can squirt fuel in ... sounds OK ... that probably explains why she fires after full throttle movement I found.

 

[billskip]

If not fitted Fit electric pump (from car )..my guess is the float chambers are at a low level ...evaporation can be an issue in hot weather.....or possibly the diaphragm in the existing pump is knackered..

 

[stelican]

It was standard procedure on inline Volvo Penta engines 3 or 4 pumps on the throttle to enrich the mixture on starting

 

[Refueler]

It was standard procedure on inline Volvo Penta engines 3 or 4 pumps on the throttle to enrich the mixture on starting

Did that today ... moving the boat so cleaning co could 'clean' my home mooring channel.

Seemed to be better .... its obviously a trick I will have to learn for this particular boat !!