2007 VP 4.3 GXI Stalling when shifting from forward to Neutral

Topcat2vin

Cadet
Joined
May 13, 2010
Messages
16
Hi,

Looking some advise. I have a VP 4.3 GXI with an SX-A leg. The boat runs great and idles fine but sometimes it will stall when changing from forward to neutral. It a real PITA when docking. Engine recently services, fuel pump cleaned - (its a little noisy but working fine)

Any ideas of what the issue could be. Note, the boat idles at about 600 RPM and will idle fine when warm.

Ideas - cable to shift interupt switch (if it has this)?
Injectors etc. - as its generally running fine I thing these would be OK?
anything else?

Thanks for the help.
 

alldodge

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Staff member
Joined
Mar 8, 2009
Messages
40,582
GXI ?

In most cases a noisy fuel pump means there is a restriction before the pump. Check the antisiphon valve which the rubber fuel line connects to the tank. Its a barbed fitting

No interrupt switch on VP

Test fuel pressure
Could be a few things idle air control, fuel pressure regulator, MAT/MAP

What was done during last service?
 

Topcat2vin

Cadet
Joined
May 13, 2010
Messages
16
Servie was basic. Oil impeller and belts. The boat was running rough so the tank was drained and I believe the fuel pump was inspected.
 

QBhoy

Fleet Admiral
Joined
Mar 10, 2016
Messages
8,286
Bad fuel, idle air control valve and perhaps just as likely...rotten exhaust/risers letting water in...would be in my top 3 suspects.
Pull the plugs to check for signs of water ingress.
 

Topcat2vin

Cadet
Joined
May 13, 2010
Messages
16
I will check the plugs but the engine has only around 70hrs so I am hoping the risers are OK. They look great externally.
Fuel is good, idle control valve - I am not sure about but my feeling is mechanic would have adjusted it if required.

Fuel pressure regulator screen is a possibility. Any photos or videos showing where it is located. (I assume as the end of a rail) also can anyone advise where to measure fuel pressure incase this is an issue.

Thanks for the help
 

Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
11,802
If the boat was running badly enough to have to clean out the tank, I'd say you should look at the anti-siphon valve at least and remove the fuel filter and dump out the contents into a large Mason jar. Let settle and see what turns up on the bottom.
There is a V/P service bulletin on the 'net floating around that details how to remove that screen I think.
Looking at the plugs is a good idea, they should be clean but still worth a look to make sure there is no oil fouling or water getting in a cyl (not likely but I still check every season). Do you see any seepage or water rust trails coming from your joint between the exhaust manifold and exhaust elbow? Those gaskets have been problematical and VP has changed them at least once to a completely different style of gasket.
 

Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
11,802
The dumping of the fuel in the mason jar is one of my favorite diagnostic tests lol. You see what's really going on in there.
as you can see no water in this fuel.....Click image for larger version  Name:	 Views:	7 Size:	140.2 KB ID:	10819643
 
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