The2 litre square port motor is running rough at idle and on deceleration...really rough to the point of cutting out sometimes. It goes really well when accelerating but on the overrun or deceleration is an absolute pig...have been focused on the fuel side of things but am I missing (no pun intended) something??? all informed opinions valued
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- Thread starter bahay
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Distributor? The fact that it is worse on overrun could indicate the vacuum advance is a factor. I would have a good look at points, dwell angle, capacitor etc plus check the ignition timing.
check the base gasket on the carburettor sounds like its sucking air in somewhere ,giving you a lean mixture at idle ,but not enaugh to make a big effect whilest running
Thanks Pontarriere, good points! Vacuum capsule holds vacuum satisfactorily, vacuum hose checked out okay, points/ capacitor have been done away with electronic disy arrangement. I will recheck timing.
Thanks Pugwash...good points again ...Tightened the big side of the square port manifold and replaced Booster and PCV hoses with similar thoughts in mind...maybe I need to do a thorough job and replace the base gasket.Thanks again Pontarrierre and pugwash
Check the if there is any play in the carburettor shafts as this can cause this problem.
Will check that out too...thanks 1pugnut
What carby are you running?
Carby could be loose as seen a few do that. Enough to suck air.
Carby could be loose as seen a few do that. Enough to suck air.
Solex SEIEA. Original manual choke. 504 carby.
Have you always been running that carb and how has it been running all along? In South Africa most folks prefer the Weber 36 DCD 7 on the 504 2 liter engines, I'm told the original Solex is not as reliable.
Update time ...carby to manifold and manifold to cylinder head gaskets both replaced, practically new sparkplugs were cleaned, brake booster and PCV hoses replaced , in line fuel filters replaced. Timing reset. It appears that the carburretor shafts don't have slop. The motor starts well enough and there's a slight improvement in "idling'' but it's still quite rough.
On advice of 1pugnut I sprayed some 'Start ya bastard' ( 25%ether spray) in places where there could be a vacuum leak; and there was a telltale slight increase in revs when spray was directed near the bracket that holds the accelerator outer cable and holds the end of throttle return spring.
Not sure what the next step is...logically should check what possible vacuum leak could come from the bracket area...
Thanks to veryone for the input advice and interest...will keep you posted
On advice of 1pugnut I sprayed some 'Start ya bastard' ( 25%ether spray) in places where there could be a vacuum leak; and there was a telltale slight increase in revs when spray was directed near the bracket that holds the accelerator outer cable and holds the end of throttle return spring.
Not sure what the next step is...logically should check what possible vacuum leak could come from the bracket area...
Thanks to veryone for the input advice and interest...will keep you posted
Decades ago, I had a somewhat similar problem with a carby 504. It turned out that, inside the distributor, the lever that the vacuum advance is connected to, was bent up so that the cam wasn't being limited, to and fro, by the square hole min the mounting plate. Might be worth checking.
Do you have a timing light? If so, I would check the change in timing when revving up and idling.
Do you have a timing light? If so, I would check the change in timing when revving up and idling.
Thanks Peter I’ll have a closer look at the distributor…so far all my vacuum/ fuel efforts have provided no joy…