Carbs maybe a bit rich

[daver clasper]

Hi everyone.

Vitesse, 150 CD carbs.

Looking at the colour of my plugs even on a run they are on the sooty side.

If I try and lean them a bit the car will hesitate on accelaration (dash pots have oil).

I can't see any black smoke if I rev it in nuetral.

Just wondering if they are running rich, will this cause any engine damage.

Any advice much appriciated.

cheers, Dave

[Nick Jones]

Running a bit rich shouldn't cause engine damage, though very rich could due to bore-wash - that would give rough running and black smoke though.

Does it use any oil (another possible reason for slightly black plugs)?

Should be noted that unless you do a true plug-cut (stop engine from cruise and check in a layby) the result is not necessarily representative.  Could just be rich at idle.

Nick

[Paudman]

Quoted from Nick Jones

Should be noted that unless you do a true plug-cut (stop engine from cruise and check in a layby) the result is not necessarily representative.  Could just be rich at idle.

Nick

Good point, that - just idling your car in the garage won’t give a true reading of the fuel mixture; it needs a good run to get the system warmed up and running right. Go out for a few miles, drive back, stop immediately and then test the plugs.

[Pete Lewis]

yes after starting on choke it takes a good few miles cruising to clean them up

Pete

[glang]

Hello Dave. You should have a small plunger on the left hand side of each carb body which is for checking mixture adjustment. It takes a bit of getting used to but   with the engine up to temp and running you lift one plunger and listen for any immediate rev change. Pick up - too rich, dying - too weak. Basically there should be no change but in my experience if you hold the plunger up for more than a few seconds the engine will falter regardless so the true indication is what happens initially. Hope that helps, Graham

[mazfg]

Quoted from glang

Hello Dave. You should have a small plunger on the left hand side of each carb body which is for checking mixture adjustment. It takes a bit of getting used to but   with the engine up to temp and running you lift one plunger and listen for any immediate rev change. Pick up - too rich, dying - too weak. Basically there should be no change but in my experience if you hold the plunger up for more than a few seconds the engine will falter regardless so the true indication is what happens initially. Hope that helps, Graham

I've tried and tried to get this method to work..but it always falters regardless...I know the engine well enough now by sound and with a vacuum gauge...can get it set-up correctly