Idle Problems: Solex 44PAI on a Volvo AQ125A

[Dr. Velocity]

I brought this up in an old thread, but I was instructed to make a new thread.

Here's the problem:

My brother bought an '82 Bayliner Capri with a Volvo AQ125A engine and Volvo Penta 270 stern drive. He took it to a shop who replaced the fuel pump and then recommended that the carburetor be rebuilt. They ordered the rebuild kit, but didn't know when it would arrive, so they took his boat off their schedule. When they received the rebuild kit, the boat went back on the schedule and they told him he would have it back in three weeks. My brother didn't want to wait, so he took the boat to a bunk-mechanic who said he cleaned and rebuilt the carb, but then flaked out. That mechanic said the spark-plug cables were shot also and that he couldn't find replacement cables.

So, now the boat is in my driveway and I'm trying to get it running. I purchased some Accel SuperStock spark plug cables and made them work for the Volvo distributor cap. They flow plenty of current just fine. I also replaced all four plugs and as far as I can tell, there is spark at all four cylinders.

I can fire the engine up and it'll run above 2000 RPM. Between 2000 and 2500 RPM, it hunts around +/- 200 RPM. Above 2500, it seems to run smoothly without hunting. Below 2000 RPM, the engine stalls. I've attempted to adjust the carburetor per the Volvo users manual for the AQ125A/270 engine stern drive combo, but I've had no luck.

Now I've got the carb off the intake manifold so I can go through and clean it and make sure none of the passages are gunked up. I've looked at the parts fiche available online, and I'm confused about one part. The accelerator pump nozzle is working fine, but what is the other nozzle for in this picture?

The other end of that nozzle sits in the float bowl and I've never seen it dump any fuel into the carb while the engine is running. It seems to be a superfluous nozzle. What is this nozzle for?

What size are the jets that were originally provided with this carburetor?

Besides carb issues, are there any other reasons this the engine would not want to run below 2000 RPM?

Is there a place online where I can find a Solex 44PAI manual?

 

[Don S]

Re: Idle Problems: Solex 44PAI on a Volvo AQ125A

I'l start by saying the 125's or any of the Volvo OHC 4 cyllnder engines are VERY picky about their tuneup. They like new points, they like the dwell to be from mid to hi part of the range, the timing has to be dead on. The advance weightes also have to work correctly.>>>> Then the carb has to work, with no air leaks.
Also make sure the timing belt is in good shape. Rusty pulleys eats them up in a hurry.
That tube sounds like it's a float bowl overflow to put the gas into the carb not out into the bilge should the float stick open...... It's a fire/safety thing.

One other note. The OEM spark plug wires have resistors in the ends that go on the spark plugs. Make sure you new automotive wires have them..... I doubt they do.
And make sure you are using the right plugs for that engine.
If you want to work on that engine, I would seriously suggest you find a Volvo Penta service manual. A brand new one from a Volvo dealer is about 20 bucks.

 

[Dr. Velocity]

Re: Idle Problems: Solex 44PAI on a Volvo AQ125A

One other note. The OEM spark plug wires have resistors in the ends that go on the spark plugs. Make sure you new automotive wires have them..... I doubt they do.

Well, you're right about the wires. I just measured 1.3 kOhm on the old wires - any idea of what resistance they should be? Or, any idea of how much current flows through the wires at what voltage? It'd be easy enough to put a 1.3 kOhm resistor inline as long as I knew how power it needs to dissipate.

The spark plugs are the correct spark plugs for that engine, according to the NGK catalog at the local parts dealer.

Is there a better distributor/ignition system available for this engine?

I'll order the service manual tomorrow. Any experience with the Clymer manual for that engine?

 

[Coors]

Re: Idle Problems: Solex 44PAI on a Volvo AQ125A

Well, you're right about the wires. I just measured 1.3 kOhm on the old wires - any idea of what resistance they should be? Or, any idea of how much current flows through the wires at what voltage? It'd be easy enough to put a 1.3 kOhm resistor inline as long as I knew how power it needs to dissipate.

The spark plugs are the correct spark plugs for that engine, according to the NGK catalog at the local parts dealer.

Is there a better distributor/ignition system available for this engine?

I'll order the service manual tomorrow. Any experience with the Clymer manual for that engine?

Bad experience.

 

[Don S]

Re: Idle Problems: Solex 44PAI on a Volvo AQ125A

Any experience with the Clymer manual for that engine?

The firing order is wrong.............
Never went any further. Was't worth spending 30 to 40 bucks for wrong information when the OEM info is only 20 bucks.

 

[Dr. Velocity]

Re: Idle Problems: Solex 44PAI on a Volvo AQ125A

Alright, I took the carb apart and cleaned it thoroughly. I have one question about the idle jet:

There are three horizontal holes and it appears there is one at the bottom of the jet. However, when I shoot carb cleaner into the bottom of the jet (the hole closest in the picture), it does not flow through. Is it possible that the idle jet is damaged? If so, is this a relatively standard jet that I can purchase at a local shop?

And lastly, as I understand the basics of carburetors, I'm still learning. The (vacuum, I assume) fitting here is connected via rubber hose to the fuel pump. What exactly is this doing?

Thanks,

Adam

 

[Scottaye]

Re: Idle Problems: Solex 44PAI on a Volvo AQ125A

I dont believe that's a hole in the bottom of the jet. Stick a small wire through to make sure. The way the inlet on the carb looks, it looks like it may be a fuel line, but surely you would have thought about that.

 

[Dr. Velocity]

Re: Idle Problems: Solex 44PAI on a Volvo AQ125A

I dont believe that's a hole in the bottom of the jet. Stick a small wire through to make sure. The way the inlet on the carb looks, it looks like it may be a fuel line, but surely you would have thought about that.

It is, in fact, a hole in the bottom of the idle jet. I cleaned it out with a pipe cleaner and it seems to be working fine now.

The carburetor is back on the intake manifold and I've ordered a cap and rotor for the distributor. In the mean time, I took some 800 grit sand paper and sanded the points a bit. Success. I was able to get the idle down to 900 or so RPM and it's running smoothly now.

I'd still like to know what this circuit does:

It's connected to the fuel pumper with rubber tubing, but I've never seen fuel flow through it.

If you want to work on that engine, I would seriously suggest you find a Volvo Penta service manual. A brand new one from a Volvo dealer is about 20 bucks.

I called my Volvo Penta dealer and got bad news. They said that the service manual is no longer in print and advised me to search the internet far and wide to find one.

As far as the spark plug wires go, I haven't put resistors in yet. The only thing I can think of is that be damaged with no resistors would the coil? If so, would I be able to use an automotive coil in the case that it fails? Otherwise I've gotta hack up a perfectly decent set of spark plug cables to put resistors in line, as I don't want to pay $140 for simple spark plug wires.

 

[Don S]

Re: Idle Problems: Solex 44PAI on a Volvo AQ125A

If the fuel pump diaphram should leak, instead of the fuel leaking into the bilge and becoming a fire/explosion hazard, the fuel will be sent thru that hose to that fitting and into the carb.
It's supposed to be dry at all times, if there was gas in it, you would need a new fuel pump.

 

[Dr. Velocity]

Re: Idle Problems: Solex 44PAI on a Volvo AQ125A

If the fuel pump diaphram should leak, instead of the fuel leaking into the bilge and becoming a fire/explosion hazard, the fuel will be sent thru that hose to that fitting and into the carb.
It's supposed to be dry at all times, if there was gas in it, you would need a new fuel pump.

That was what I was thinking, thanks for confirming it.

(You can probably tell, but I grew up with fuel injection and electronic ignitions )

 

[bobb2003]

Re: Idle Problems: Solex 44PAI on a Volvo AQ125A



It is, in fact, a hole in the bottom of the idle jet. I cleaned it out with a pipe cleaner and it seems to be working fine now.

The carburetor is back on the intake manifold and I've ordered a cap and rotor for the distributor. In the mean time, I took some 800 grit sand paper and sanded the points a bit. Success. I was able to get the idle down to 900 or so RPM and it's running smoothly now.

I'd still like to know what this circuit does:

It's connected to the fuel pumper with rubber tubing, but I've never seen fuel flow through it.




I called my Volvo Penta dealer and got bad news. They said that the service manual is no longer in print and advised me to search the internet far and wide to find one.

As far as the spark plug wires go, I haven't put resistors in yet. The only thing I can think of is that be damaged with no resistors would the coil? If so, would I be able to use an automotive coil in the case that it fails? Otherwise I've gotta hack up a perfectly decent set of spark plug cables to put resistors in line, as I don't want to pay $140 for simple spark plug wires.

You don't need resistor type ignition wires. Those only help reduce EMI so you don't have interference with AM radio for the most part. Doesn't really have much effect on the spark.