Solex 44PA!

[normanr25]

Hi Guys
I have an AQ130C with twin Solex 44PAI carbs, My fuel pump packed up and since I replaced it the carbs won't prime I have checked for fuel or air leaks and all is ok it will start by cranking the engine but after leaving the boat for a few days it really struggles to start but when I could prime the carbs it was a really good starter.

Once started it runs great so the pump is working fine, accelerates and ticks over with no problems any help would be appreciated

 

[Scott Danforth]

check your anti-siphon valve

 

[normanr25]

Sorry where do I find that

 

[dennis461]

Sorry where do I find that

On another boat

The Solex fuel bowl is top feed, fuel should not flow backwards.
The mechanical pump also prevents backflow.
Perhaps the new one has a problem.
or
The carbs have a leak.

Next time before starting, CAREFULLY open the flame arrestor and look for gas in the carb throat.
Pump the throttle and look for a squirt of gas. WITH IGNITION OFF.

 

[normanr25]

On another boat where is that coming from,? just asking a question.
No I have already tried that and no not getting a squirt of gas

 

[Scott Danforth]

Anti siphon valve is on the fuel tank, its a one-way check valve to prevent fuel from back-flowing to the tank

 

[normanr25]

Many thanks Scott I will check that out can,t think what else it can be

 

[dennis461]

No Title

Could it be that both carbs are loosing gas from the diaphragm in here;

 

[normanr25]

Hi
This one is a complete mystery other fellow boaters in the marina with same engine and carbs can't understand why it is not working.

New carb sets with diaphragms,jets and gaskets all replaced as I said in original post one it starts it runs great but because it won't prime cold start without turning it over loads of times not doing the old starter or batteries any favours all pipe work checked for leaks,new gas filter pump tested and all as it should be.

Thanks for both you guys for your advice but I think this needs and engineer that knows the setup and problems with these old engines, I looked yesterday and there is no anti-siphon valve on the gas tank and never has been it is was a brand new stainless steal tank fitted a 12month ago and was working 100% then there is obviously something silly somewhere that me and the other guys in the marina are missing

 

[Fishhead-1]

what Dennis is trying to confirm is are the bowls still full of fuel, if they were the accelerator pumps would both squirt fuel down the carb. What do these carbs use for a choke?

 

[Fishermark]

The anti-siphon valve is not designed to keep the fuel from flowing back into the tank. It is designed to keep the fuel from siphoning from the tank into the bilge in the case of a fuel hose leak. Those carbs are notorious for being hard to start when cold - especially after a long period of non-use. And, (my personal opinion - not necessarily backed up with real evidence ), is that today's fuels tend to evaporate more easily than they used to. It seems that fuel today is more suited to fuel injection than to carbs. All I know is all of my vehicles that use carbs have more trouble today with cold starts after a long layover that they used to. Those carbs also do not have a choke - which makes the situation even worse.

Now if this is truly only happening now that you have changed the fuel pump, then I might have an issue with a bad pump.

 

[normanr25]

Been to boat today and yes both carbs were full of gas but still not squirting fuel through the priming tubes.

As I said guys you have told me all the obvious problems I am going to leave it until next year now it is getting colder now so I have plenty to do apart from that problem,

As regards the pump that has to be OK otherwise the float chambers would not be full and as you are saying if the float chambers are full the diaphragms should pump full into the carbs

 

[PiratePast40]

If the float bowls are full of fuel, then yes, you should see gas squirting out of the candy canes when pumping the throttle. There could be debris in the accelerator pump passages, leaky diaphrams, or the springs may have been installed backwards if an aftermarket manual was used as a guide for reassembly. You mentioned that the carbs had new kits and gaskets. Were the carbs thoroughly cleaned? I ask because those carbs do not tolerate debris or varnish in the passageways. As a very wise man once mentioned on these forums, "not all carbureator rebuilds are successful".

 

[dennis461]

and...
there is no choke on these carbs.
if not squirting, then the rebuild was less than adequate.
My boat runs great..only took three rebuilbs on the carbs to get it working!
The accelerator pump (needed for acceleration in addition to starting) uses the spring to apply pressure, that way is is more or less independent of how fast you throw the throttle. It is also adjustable for volume, the tiny nut on the end of the lever in my picture.
It could be the rebuilder forgot to screw it to the correct position.
Does the lever move to starboard as the throttle is pulled forward?

 

[normanr25]

Hi Guys thanks for all your help and carb is working 100% now squirting into carb as they should, hope this will be of some help to other members with one of these carbs.

I bought a sonic cleaner and gave the carbs a good soak and it wasn't until I did this clean that the jet attached to the bottom of the float bowl has a very very fine piece of gauss that fits into the hole and that was completely blocked with gunge and as I said it is very fine so I didn't even know it was there until this clean.

So all sorted now thanks to all for your help as I have said before this is a brilliant forum we would be lost without it because there are so many knowledgeable members,

Can't thank you all enough
Norman

 

[dennis461]

You called the small screen 'gauss'. I think in mine it is a small brass barrel shaped screen. Not in any rebuild kit I ever bought.
Glad you got the antique working!

 

[normanr25]

Yes as you say say Dennis small brass barrel shaped screen and considering the price of the rebuild kit you would think they would put one in.

I have had problems with them again so getting rid of fed up with them keep causing problems, a mate of mine with the same engine did a weber conversion at the beginning of the year and it works great so I have bought the conversion and will be fitting to my boat as soon as poss

 

[PiratePast40]

I found some OEM parts kits on e-bay a couple of years ago. Those had the screens, floats, and replacement bolts and screws in the kits. Unfortunately, haven't seen those kits since.

 

[normanr25]

Yes that is a proper kit but as you say all the kits do not have all those parts with them now, these carbs are 40 years old now and parts are a stupid price for what you are getting so as I said time to modernize and hopefully get rid of fuel problems which is all I am getting with this old boat now.

The other thing to do I suppose is replace the engine with a more modern one but in my case not worth the expense I have spent enough on it as it is and getting to the stage where I would be loosing a shed load of money when selling time comes up.