85 Bayliner Carb adjustment

[hank3rd]

Hello all,

I have an 85 Bayliner Capri with a Penta AQ125b motor. I bought and installed new gaskets and overhauled the carb. I screwed in the adjustment screws after cleaning them and need to know what each one is. The boat runs then stalls and I am going to try to adjust it this week. I know the rule of the 1 11/2 turns out, but I there are two screws at the top if the unit and one at the bottom (that has a spring).

Can someone tell me what each one is to help me with the adjustment. I tried to locate a manual or picture, but could not.

Thank you for the help.

 

[captmello]

Re: 85 Bayliner Carb adjustment

I looked at the owners manual, which you can download at the following link. Just type in aq125b in the engine type box and scroll down.

http://www.volvo.com/volvopenta/global/en-gb/marine_leisure_engines/parts_service/publication_search/publication_search.htm

from what I could see the is one air screw towards the bottom. all the way in and then back one turn. It also showed the idle adjustment by the throttle linkage.

Good luck!

 

[hank3rd]

Re: 85 Bayliner Carb adjustment

Thank you! I will look at it as soon as I put the new starter in tomorrow. I think there is three screws, but I could be wrong. If I have any further trouble, I will post some pics of the carb. At least I know how to adjust two of them.

 

[hank3rd]

Re: 85 Bayliner Carb adjustment

I had the vessel out this weekend and it starts up, but keeps stalling. I know that the carb is not set right and there is a screw at the top that when I adjust it outward, will allow for the engine to run when I push the throttle. When the screw is all the way in it will bog and stall. I noticed as I run it, the screw tightens itself. I think there may have been a spring on the needle valve, but is now missing. I am going to pick one up.

The question I have is what does each screw do? There is on at the base, that is alone and has a spring on it. I am thinking it is the idle? Then there is on on/near the throttle linkage which I though was the idle, but the before mentioned screw seems to do that as well. Then there are two screws near the top of the carb, near the plate that the air cleaner rests on. One of which is the one I mentioned in the top paragraph. So there is a total of 4 screws and all of the research I have done calls for three and the manual linked here shows 2. I was hoping that someone might know this and help me out. I was going to try to take pics but it is in an awkward area.

 

[captmello]

Re: 85 Bayliner Carb adjustment

Sorry I have not worked on that carb before. Have you studied the parts breakdown to see if your missing a spring?

from the VP parts site:

http://www.volvopentastore.com/CARBURETOR_841533/dm/*******.486029580--**********.564576332--store_id.366--view_id.327284

#26 looks like the Idle adj.
#24 Look like the idle air adj.
# 7 listed as an adjuster screw

Did you replace the diaphragm in the accelerator pump?

Let us know what happens.

Good luck.

 

[Robj]

Re: 85 Bayliner Carb adjustment

That carb looks similiar to mine. It looks like number 24 is the mixture screw. Turn it in all the way and back it out 1.5 turns. Start the engine, slowly turn the screw in until the engine starts to run poorly, then back it out 0.5 turns. If the engine is still not running right, I would check your ignition timing.

Have a great day

Rob.

 

[hank3rd]

Re: 85 Bayliner Carb adjustment

I found a repair manual for an AQ125A and I have a B, but looks the same. I think it sais that #7 holds in #6 "fitting" and does not play a role in the settings. There does not appear to be a spring for #11, but I bought one this morning. Hopefully that will help with the screw turning back in.

I am starting to get an idea as to what I need to adjust now and hope that I can tune it soon. I was doing it willy nilly the other day and now have more info. I will report back.

thanks for the help!