Problem with Volvo Penta 3.0l not returning to idle

[scb1712]

Hi,

I've got a 2000 Volvo penta 3.0l GS-PEFS engine. I'm not sure if this is a carb issue, an adjustment issue or a linkage issue. The engine runs well but once it is warmed up, it will not return to it's proper in-gear idle at 800 rpm. It tends to sit around 1000-1100 instead. If i lift the engine hatch and tug gently on the trottle assembly, it comes right back down to 800 and will stay there until i use the throttle lever again.

I'm hesitant to just back off the idle adjustment since it seems to idle at the correct RPM when i tug lightly on the throttle assembly. I have tried to adjust the idle linkage to "push" on the throttle assembly more when i pull the lever back to idle but that hasn't seemed to help at all.

Any thoughts??

 

[scb1712]

Re: Problem with Volvo Penta 3.0l not returning to idle

Any ideas? Anyone??

 

[Don S]

Re: Problem with Volvo Penta 3.0l not returning to idle

The idle rpm should be 650 to 700 rpm, not 800.

Disconnect the shift cable from the carb linkage and make sure when you pull the throttle back to idle that it puts a light pressure on the linkage to the idle position. Adjust the eye on the end of the cable as needed.
As the cables get older and worn inside, they develop more free play which changes the adjustment.

 

[scb1712]

Re: Problem with Volvo Penta 3.0l not returning to idle

Thanks Don. I've adjusted the linkage as you suggest, but i dont think i have much thread left. The badge on the top of my valve cover says 800rpm, but i'll try adjusting the RPM down to the range you suggest and see what happens. Just to be sure, you're saying in-gear idle at 700, not neutral. Correct??

 

[scb1712]

Re: Problem with Volvo Penta 3.0l not returning to idle

Okay - so the idle speed adjustment screw is backed out all the way and she still sits at 1100 rpm unless i tug on the trottle assembly. Also, i can't adjust the linkage any further as i'm out of threads. Does this mean that i'm going to need that carb rebuild sooner than i had planned??

 

[scb1712]

Re: Problem with Volvo Penta 3.0l not returning to idle

Hello? Any other suggestions out there??

 

[Don S]

Re: Problem with Volvo Penta 3.0l not returning to idle

Will it slow down to the proper idle and be adjustable if you disconnect the cable? A carb rebuild is not going to help you close the throttle plate. Post a picture of your linkage setup and how the cable is attached.

 

[scb1712]

Re: Problem with Volvo Penta 3.0l not returning to idle

Hi - was out of the country for a couple of weeks for work but am finally able to post pics. Tried to adjust things again but it always ends up with the same result. To answer your question - it does not return to normal idle even with the linkage disconnected, which leads me to suggest a carb issue. Just not sure what i can adjust.

Anyway - here are a few photos of the carb linkage as food for thought.

 

[newish]

Re: Problem with Volvo Penta 3.0l not returning to idle

Hi - was out of the country for a couple of weeks for work but am finally able to post pics. Tried to adjust things again but it always ends up with the same result. To answer your question - it does not return to normal idle even with the linkage disconnected, which leads me to suggest a carb issue. Just not sure what i can adjust.

Anyway - here are a few photos of the carb linkage as food for thought.

View attachment 159878View attachment 159879View attachment 159878View attachment 159880View attachment 159881

What about your return spring on the carb? does it have the holley on it? if so u can take the spring off and run to your local parts store and match one up!

 

[spanerhead4444]

Re: Problem with Volvo Penta 3.0l not returning to idle

hi looks lick sum W.D.40 & greas mite help

 

[dypcdiver]

Re: Problem with Volvo Penta 3.0l not returning to idle

You might want to check the security of the anchoring of the outersheath of the cable at BOTH ends. Also see an earlier post regarding where the anchor block should be secured on the engine mounted plate, just incase it has been assembled incorrectly.

 

[scb1712]

Re: Problem with Volvo Penta 3.0l not returning to idle

Thanks for the tips. I'll try cleaning things up and then double check the return spring. Hadn't thought of that before...

 

[Don S]

Re: Problem with Volvo Penta 3.0l not returning to idle

Marine engines don't have return springs.

If you disconnect the cable, start it up adjust the idle speed screw out while holding the linkage against the idle stop screw, will it slow down? If not, then you probably have a vacuum leak somewhere allowing air in.

 

[scb1712]

Re: Problem with Volvo Penta 3.0l not returning to idle

Thanks Don - i'll give that a try this weekend. Just to be sure we're on the same page, if i tug on the linkage to bring the idle down, it will then stay at the lower RPM. Would that still be indicitive of a vacuum leak?

 

[skydiveD30571]

Re: Problem with Volvo Penta 3.0l not returning to idle

Thanks Don - i'll give that a try this weekend. Just to be sure we're on the same page, if i tug on the linkage to bring the idle down, it will then stay at the lower RPM. Would that still be indicitive of a vacuum leak?

Probably not. So with your throttle cable disconnected from the carb, you can pull the linkage towards you and the idle comes down correct? But your issue is that the carb doesn't want to do it on it's own? What Don is referring to is an adjustment of idle speed. Since you've already determined that the carb can close to where it should be if you give it a little persuasion by tugging on the linkage, you just need to adjust the throttle cable so that it does the "tugging" for you when you move the controller back to idle. Remove the play in the line and adjust the eyelet piece on the end of the cable so that it just barely pushes the linkage closed when the controller is brought back to idle. Test it out, and if it needs a little more push, adjust it from there.

My carb is the same way, it almost returns to idle on its own, but just barely stops short (about 100rpm high). I adjusted the throttle cable to close it that last little bit and all is good now.

 

[Don S]

Re: Problem with Volvo Penta 3.0l not returning to idle

I think one of the reasons you are having problems is your throttle cable is out of adjustment in the throttle control itself. Has the cable been replaced.
If you look at this picture, you will see you have very few threads holding the end on at the carb. You need a full 9 threads (1/4") minimum of the cable end on the cable. You may have to readjust the cable in the control, or the cable itself is worn out and too much slop in it to be able to adjust it any more.

 

[scb1712]

Re: Problem with Volvo Penta 3.0l not returning to idle

You may be right Don. We've wound out the connetor at the carb end so that there are only about 2-3 threads holding it on in an attempt to get the cable to put more pressure on the linkage to bring the idle speed down, but it hasn't seemed to work at all. I'll have another look at the other end at the throttle control and see if i can make any progress.

 

[trophy boat]

Re: Problem with Volvo Penta 3.0l not returning to idle

Adjust the cable at the throttle control at the helm to get you some more cable. I had the same problem after changing out my cable last year.

 

[scb1712]

Re: Problem with Volvo Penta 3.0l not returning to idle

I'll start trying to adjust the thottle control end to see if we can make any progress. My throttle control is difficult to get at, but i think i can manage. Is there any benefit to removing the lever from the transom or should i just try to get my hands/tools up in there?

 

[comptre]

Re: Problem with Volvo Penta 3.0l not returning to idle

Sir: Did you ever resolve this idle issue. I have 2009 Volvo3.0 with same issue. Idle is good on start but returns to 1100RPM after running. Causes engine to diesel on shutdown. My carb has been removed and cleaned and the cable adjusted at Volvo shop. ILocal marina store has 88OCT non ethanol which I use. On mechanic suggestion I have gone to higher octane but seems to make no difference.