How to diagnose no fuel to carb?

[JAL51974]

This is a volvo AQ125A with the single solex carb. Tried to start for the first time this spring 2 wks ago only small amount of fuel seen at carb. Meanwhile I repaired the starter problems I was having so only got back to the startup tuneup today.

Starter cranks fine but engine won't run. I inspect the carb and no fuel going to bowl despite however i tried to pump it. I pulled the line from tank to fuel pump, inserted a bulb like used on outboards, and I got good gas flow up to the fuel pump. Again tried to start using throttle, with same result, but now I know fuel is flowing to the fuel pump. I then slightly loosened the fuel supply line attached directly to the carb, and immediately got a good spray of fuel there so the line is working fine up to the point where the fuel enters the carb.

Is there any thing else I should do before removing and rebuilding the carb?
No fuel supply probs all last season and when I winterized it in the fall no problems starting it up or anything either.
How hard is a carb rebuild since I have never done it before?
Where is a good place to fine the rebuild kit online...noplace stocks these volvo parts near me!

Thanks,

Joe

 

[pjb0422]

Re: How to diagnose no fuel to carb?

What I would do, if I were you, is to get some carb cleaner and spray into the carb where the fuel line connects. I would also spray the jets in the carb too. It could be that you have some varnish build up that is stopping the fuel flow.

Phil

 

[f_inscreenname]

Re: How to diagnose no fuel to carb?

Carb rebuilds are like brain surgery. If it ain't right ......

But before I would do anything try looking down the carb and moving the throttle linkage. See if the jets are squirting.
Or you could try tapping on the side of the carb. Sounds like the float is stuck.
Or you could dump a tiny bit of gas down it then try starting the motor.
From there you will know where the problem is.

 

[Don S]

Re: How to diagnose no fuel to carb?

You may have the carb full of gas, but if the acclerator pump circuit is either plugged up or not working, it won't pump fuel into the throttle bore thru that little U shaped tube at the top of the carb.

Have you looked for parts at the top of the page just above your original posts. Click on the words "Volvo Penta Parts"

 

[JAL51974]

Re: How to diagnose no fuel to carb?

thanks for the quick replies.

There is definitely no fuel squirting from the J shaped jet, pump accel. now. It was squirting but only a little that first day I tried to start it up several wks. ago. I will try tapping the side to free the float. To spray carb cleaner into the carb where the fuel line connects I will have to loosen that fuel line, and that is the one I only slightly loosened today and got a spray of fuel, so there is definitely pressure upto that point. Any suggestions to relieve that pressure?? Also to spray carb cleaner into the jet itself will be nearly impossible as that is an upside down J shaped piece, no way to get at it with the spray I think.

My thought is that J shaped pump accel. is plugged with crap sucked up from the fuel tank as there is no inline filter on this engine and no filter anywhere that I see on this carb, unless its somewhere inside the carb itself and plugged up with gunk in there.

Joe

 

[sarantis]

Re: How to diagnose no fuel to carb?

put a clear hose from pump's outlet to carb's inlet.Easy to find the hose at an auto shop and the 2 connectors at a marine shop.Put a friend to turn the Key and watch the gwsflow but be careful,this system is not safe ,only for check.

 

[Fireman431]

Re: How to diagnose no fuel to carb?

Solex carbs are very easy to rebuild. Probably one of the carbs with the fewest removable/adjustable parts. First try sliding a small piece of wire into the spray tube. It might just be varnish/gunk clogging it up. Then look for a stuck needle/seat in the float bowl. If the float integrity has been compromised, then it will be filled with fuel and not allow the needle to open, thereby leaving the bowl dry. Usually quick fixes with a rebuild kit. Follow the instructions and use the included ruler to set the proper float levels for best performance.

 

[JAL51974]

Re: How to diagnose no fuel to carb?

There is definitely fuel pressure at the inlet to the carb body, as I gently loosened the fuel line at that point I got a good spray!

I will try the wire into the spray tube that J shaped one right?
I will also try tapping gently on the u-shaped tube near the post on the top of the carb- the float needle valve is under that I think from studying the manual diagram.
If all else fails a rebuild is coming up next.

Only good thing is it happened now and not in the middle of the boating season, and our weather has been crappy here so I am not missing any time out on the lake anyway.

Joe

 

[Coors]

Re: How to diagnose no fuel to carb?

Time to rebuild the carb. If you have fuel to it , and it can't get into the venturies; it is gummed up inside, and carb cleaner is a waste of time.
Get a kit, some 1 gallon gunk carb cleaner, and google carbs, as it soaks.
Not hard, just read, while it soaks overnight.

 

[JAL51974]

Re: How to diagnose no fuel to carb?

Glad to report that the"tapping" idea worked! While the fuel was under pressure to the carb via the bulb I tapped all around on that hump place on the carb top plate and I inserted the finest gauge wire from my wife's sewing materials just up that J shaped jet. Nothing different, no squirting at first but as I pumped it a few times from the throttle I saw a few drips then it kind of let loose in a normal stream.

The engine started right up after that and I let it run about 10 min. on the muffs. Now I need to disconnect the bulb and finish the tune up...seems to be running a little high idle but I knew that needed some work anyway so its not a surprise.

What do you think about rebuilding the carb or can I just let it ride and see if I can do it in the fall? Not sure when (if ever) it was rebuilt.

I have an appointment with a marina tomorrow to replace the drive bellows and inspect the u-joints...I hope all is well there!

Thanks.
Joe

 

[Don S]

Re: How to diagnose no fuel to carb?

You haven't fixed anything yet, all you did was temporarily unplugged and unstuck things. Read what it says below my name.

 

[JAL51974]

Re: How to diagnose no fuel to carb?

Yeah I think I will order the carb rebuild kit and plan on doing it, better to be safe than sorry. Thanks.

Joe

 

[nyteez]

Re: How to diagnose no fuel to carb?

We have the dual solex carbs. The manual was helpful in finding all the parts that need to be cleaned. Didn't even get the rebuild kit, just carefully disassembled, put all parts in a bowl of wd-40, cleaned all gunk & stuff out of jets and put back together. Much easier than we thought and only took about an hour.