Solex PA44 Volvo Penta AQ131A Adjustment - Wont idle

Ed Idaho

Cadet
Joined
Oct 20, 2009
Messages
12
I rebuilt the Solex PA 44 on my Aq131a using Mikes Carbs video and parts.

No matter what I do to adjust the fuel mix and idle it just wont idle correctly. It seems to be fine but when I rev it up and then throttle down it takes forever to respond and idle down. Then it idles fine for a short time and then kinda roller coasters RPM until it starts coughing and missing and dies.

It will idle well at RPM that is above an idle it should be shifted at... cant seem to get it to idle at a low enough rpm to comfortably shift.

I recently replaced the fuel pump.

I tried running the engine using fresh gas by placing the fuel line in a new can of gas. No luck.

Any one know of a similar problem with a solution?

Thanks for reading...

Ed
Nothin works on an old boat except the owner.
 

PiratePast40

Lieutenant Commander
Joined
Mar 21, 2009
Messages
1,734
Re: Solex PA44 Volvo Penta AQ131A Adjustment - Wont idle

Someone on this forum once wrote "..not all carb rebuilds are successful". There are many things that can go wrong, including not completely cleaning some of the passages.

First thing that I'd check is if the accel pump is pumping gas through the 'candy cane', and then check for vacuum leaks. May need to verify that the accel pump diaphragm is installed correctly. Would be a good idea to verify the timing as well. That will have an impact on ability to idle.

That particular carb is relatively simple, but like anything else, it must be put back together correctly.
 

Alan Lloys

Petty Officer 3rd Class
Joined
Aug 16, 2012
Messages
99
Re: Solex PA44 Volvo Penta AQ131A Adjustment - Wont idle

I rebuilt the Solex PA 44 on my Aq131a using Mikes Carbs video and parts.

No matter what I do to adjust the fuel mix and idle it just wont idle correctly. It seems to be fine but when I rev it up and then throttle down it takes forever to respond and idle down. Then it idles fine for a short time and then kinda roller coasters RPM until it starts coughing and missing and dies.

It will idle well at RPM that is above an idle it should be shifted at... cant seem to get it to idle at a low enough rpm to comfortably shift.

There are some things that sounds a little odd to me here.
It should idle down pretty much immediately when you throttle back. You may have a sticky throttle plate so it takes a little while to close up.
Try to disconnect the cable and just move the throttle plate lever with your hand. Does it return by itself or is it sticking?

I just repaired an identical (dual) carb setup and it threw me off that the throttle plates were sticky. It would not idle down properly and once it finally did it would run at way too low of an idle and die.
Sounds somewhat similar to what you have.

Make sure you have the gaskets around the plate under the carb. On one engine I worked on the gaskets were bad and it sucked in false air. The engine would run great but would not idle.

Also remember that these engines are pretty cold blooded. You want to get the temp up to around 150+ before you can throttle down to idle and shift into gear. It is "normal" for these engines and it is in the instruction manuals from Volvo.
 

Ed Idaho

Cadet
Joined
Oct 20, 2009
Messages
12
Re: Solex PA44 Volvo Penta AQ131A Adjustment - Wont idle

I figured I would get an email letting me know some one replied to my question....guess I should investigate that
I finally decided to look! Thanks to both replies.

I thought same that the rebuild was wrong so basically went back thru the entire process and used some gasket goo to seal things better, I did not use it on the main new gasket between carb and engine I can try that

Same behavior after second rebuild. They are cold blooded! I know that for sure, even more so in North Idaho where the water just got done being ice!

I explored the linkage and sticky plate theory myself, when I throttle down by hand at the carb it does idle down quicker but still seems to be a delay. i shall explore that more. I dont know how to determine if I have a vaccuum leak... I shall explore that also. Vacuum to me is a Hoover you use on carpets. Thanks again for your replies

The carb is simple, that what irks me.
 

raven1978

Petty Officer 3rd Class
Joined
May 19, 2009
Messages
99
Re: Solex PA44 Volvo Penta AQ131A Adjustment - Wont idle

The easiest way to check for a vacuum leak is to spray some intake cleaner or brake clean around your mating surfaces. As you are spraying, listen for a change in rpm. If there is a change then you have a leak,if not then no leak.
 
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