Volvo Penta AQ131C Carburettor Not Priming

[The Last Englishman]

Hi All,
Have just de Winterised my Two AQ131C volvo Penta engines and have a problem with one of them
Normal process to start engines is to pump Throttle a couple of times to prime the Carb put Throttle into neutral with a little bit of throttle and start the engines.
One engine started fine as normal the other just kept turning over and not starting

so to cut a long story short compared both engines and found that the one that wont start is not getting any fuel when priming, so added a bit of fuel to the carb and engine started and ran as expected with fuel entering carb as normal when throttle was moved
engine ran for 20 minutes before i stopped the engine. when trying to restart it it fired up good as gold and ran as normal.

When trying the priming process again no fuel came from the Priming nozzle so when the engine cooled down it did not start again until i added a small amount of fuel direct to the carb

So Fuel Pump seems ok, Fuel is getting from tank to carb when running but no fuel is getting to the carb when priming

Can anyone explain what they think is happening, what i should check to ascertain what is wrong?

I dont have pictures ATM (forgot to Take them) will do so over the next few days if that will help

Many Thanks for your help in advance

TLE

 

[spannerman]

You need to strip the carb and check the accelerator pump, either the piston is stuck at the bottom of the bore, or the non return valve between the float chamber and the pump bore, usually a ball bearing with a spring behind it is stuck/ rusted open. Seen this fault frequently after the carbs have stood over winter.

 

[Freebee]

don't forget modern petrol (with ethanol) attacks old rubber diaphragms, o rings, hoses and seals unless they have been changed for up to date spec items especially if they have been soaking over winter in fuel