Volvo Penta 5.7 over revs when starting

NAIA2

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Jul 25, 2014
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16
when starting my 5.7 GXi-C VP it over revs and sucks air loudly. Throttle is in neutral. Replaced fuel pump last year, had problem with connection on it this year but re-wired it and ran well for awhile. Now when I start it it revs to about 2500 rpm. ? fuel pressure regulator or?
 

NAIA2

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Jul 25, 2014
Messages
16
Add: can't find any vacuum leak. runs fairly smoothly but won't idle less than 2500 RPM. Throttle linkage appears grossly normal in closed position, sucking air loudly into throttle body, I presume cuz getting too much gas? is there a choke or feedback mechanism or something resulting in too much gas flow? Recently there was a leak from the raw water pump [I replaced it], but it did result in a lot of salty ocean water misting over the front of engine as it was running, including the fuel pump. This resulted in the breakdown of one of the "quick click" connectors to the fuel pump which I rewired. It ran OK after that Maybe there is corrosion inside the fuel pump resulting in pumping too much? Any ideas?
 

alldodge

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Mar 8, 2009
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Appears our VP guys are not around so I'll give a go at it. Extra fuel going in the intake will not cause the engine to idle faster, it will actually do the opposite. Start by disconnecting the throttle cable going to the throttle body on the motor. Once disconnected, open close the throttle body a few times to see if it is not hanging up and moves freely.

Start the motor with the cable disconnected and see if it still idles at +2000 RPM
 

NAIA2

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Jul 25, 2014
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thanks for your posts. I pulled out the IAC valve and manually extended the pintle, [it was all the way in] and put the valve back in and the boat started and idled properly. I think it is broken or faulty, so will replace. Any problem with using a GM [Delphi] part from an auto parts store versus a "marine" part? They look identical and $30 vs $230.
 

alldodge

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thanks for your posts. I pulled out the IAC valve and manually extended the pintle, [it was all the way in] and put the valve back in and the boat started and idled properly. I think it is broken or faulty, so will replace. Any problem with using a GM [Delphi] part from an auto parts store versus a "marine" part? They look identical and $30 vs $230.

No problem, the GM part is the way to go
 
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