Volvo Penta 3.0L Carb throttle shaft leaking

[fcawth]

I ran my 3.0 GSP-A volvo engine today (on muffs). I cranked it for a short time and it didn't start at first, so I went back and looked things over. I noticed a drop of fuel coming out at the throttle shaft. I disconnected the throttle cable, and the shaft moves around quite a bit in the hole (i.e. there is play). There is also some fuel (not enough to drip) on the other side of the shaft (under the electric choke). I think the fuel from pumping the accelerator pump a few times ran along the throttles and along the throttle shaft through a failing seal.

I see a warning in the manual that says not to clean the throttle body in carb cleaner because you can eat the teflon bushings. Perhaps a previous owner did this... Are these bushings replaceable?

I also have a hard time getting a low enough idle, and I am thinking that there is air getting sucked in around the throttle shaft. The throttle cable has some slight pressure pulling back, but I can back the idle screw all the way out and I get around 1000RPM in neutral. I can push it around by hand to get down to 800 or lower, but I think I am changing where the air leaks in (i.e. above or below the throttle). The engine is also a bit hard to start cold (again sucking air in would reduce choke effectiveness)

It is a Holley carb, and it has 3857981 80316-3 and 2270 stamped on it.

A new carb is really expensive, but do I have any options here? Is it possible to get just the throttle body? Volvo lists 3857982 for the part number of the carb, and there is no 3857981 listed. Should I be concerned about this?

I can't find any of the numbers on the Holley site.

Is there anything else I should check? There is only one vacuum line going over to the choke, could this leak enough to cause the high idle?

Thanks.

Fred

 

[fcawth]

Re: Volvo Penta 3.0L Carb throttle shaft leaking

I have been digging around trying to find my options but I could really use some help here. Should the throttle shaft be fairly "tight"? Could a loose throttle shaft cause inconsistent and high idle? Do I have to get a $700 volvo carb to replace this one?



Thanks,
Fred

 

[Maclin]

Re: Volvo Penta 3.0L Carb throttle shaft leaking

Yes, the throttle shaft bushings can leak enough air to cause a high idle due to the "vacuum" leak.

I have only fixed one or 2 carbs like that, but they had metal bushings and the guy helping me just had stuff like that laying around.

As far as parts, I am sorry I cannot help there.

 

[fcawth]

Re: Volvo Penta 3.0L Carb throttle shaft leaking

Thanks for the reply. I am going to get a refurbed marine holley carb and not mess with the one I have. I believe that the throttle cable was not adjusted properly and was putting way too much pressure on the linkage and vibration caused the wear. Since I can change the idle by several hundred RPMs by just moving the linkage around (while against the idle stop), I'm hoping the new carb solves the problem. It is amazing how a fairly small amount of slop in the throttle shaft can make such a big difference in setting the idle.

Thanks again - it's really great to have people that know what they are doing help us "regular folks" with stuff like this.

Thanks,
Fred

 

[JustJason]

Re: Volvo Penta 3.0L Carb throttle shaft leaking

Yep your only option is to replace the carb. It does not take much unmetered air to throw the idle all off.

 

[Bondo]

Re: Volvo Penta 3.0L Carb throttle shaft leaking

Should I be concerned about this?

Ayuh,... Glad to hear you found a Cure,.... Definitely needs attention...

As noted,... Carb bodies can sometimes be brought back for the Dead,...
But,.. It takes a Very Well equiped Shop to do it...
Like the place that Refurb'ed the 1 you're getting....