Yes with a firm grip on shaft,
Pump should turn easily by finger pressure.
fit a new nozzle.
as for algae... I have never seen any in 40 + years on the tools.
Are all your flue ways clear on boiler.
It will be the coil.
A shunt pump.
What does your oil pressure and vaccumn gauges tell you is happening.???
Try closing the flue damper a bit more , also ash pit door air screw.
Are the doors sealing correctly?
FFS its only an air vent.
Bung in vent and f/e and new 1/8 or 1/4 vent.
It looks very similar to the cheap and nasty auto vents.
Are we supposed to guess the Boiler/ burner and fire valve details??
I tried but my crystal ball is foggy today!!
What size pipework is feeding these new rads.
It is probably the capacitor needs replacing if it works with a helping hand.
Plenty of videos of this on net.
Run a litre of oil into a clear bottle and check for water in fuel.
Clear hose ???
Which bit are you looking at.
That is defo a long life hose!
why did you replace the pump.
Did you fit a new dog ?
Remove cover of old pump and post picture of filter and metal work.
Hold the middle one still and undo top one Or Remove the 4 screws holding the burner cover and bleed at the pump.
It's a rubber ball that sometimes detaches itself.
The diverter valve needs to be checked for correct operation before any flushing is done!!
Sounds like it is sticking or fooked.
Is it the VC...
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