Hi, after all the work I did to get my P6 running, I had an old retired BL mechanic come around to set up my carbs, ignition etc. It goes like a rocket now, it is amazingly quick. The only thing is, now when I come to a junction and stop fairly quickly it stalls. Its like it doesn't get into first quick enough and it is kind of locked into second. What can this be? It didn't do this before.
V8 tuned today..
- Thread starter phil
- Start date
Something that the retired BL mechanic did isn't correct, that is why it didn't behave this way prior to him touching it. Ideally you should ask him exactly what he did with the carbs and what change he made to the ignition timing,...what he set it to etc.
Ron.
Ron.
Hello Phil,
Setting the ignition timing to TDC @ 600 rpm for the 10.5 : 1 CR engines is what the book says to do. Typically, carbs way out of balance or the idle mixture too rich or the ignition timing incorrectly will give the symptoms you describe. Go for a 15 min drive or so, leave the engine running, pop the bonnet and raise each carburettor lift pin in turn. What happens to the idle speed when you do this?
You will find the lift pins at the rear of each carburettor, you will see a little pin with a spring around it. Pushing the pin raises the piston which will give an indication of how close or how far out the idle mixture is for each carburettor. Now this applies to HIF6 carbs, if you have HS6 carbs I cannot be certain if there is indeed a lift pin on that model. In which case if there is not, you will need to detach the elbows from each carburettor and then using a large flat bladed screw driver, very gently raise each piston only a mm or two and listen to the idle speed as you do this. What happens?
Ron.
Setting the ignition timing to TDC @ 600 rpm for the 10.5 : 1 CR engines is what the book says to do. Typically, carbs way out of balance or the idle mixture too rich or the ignition timing incorrectly will give the symptoms you describe. Go for a 15 min drive or so, leave the engine running, pop the bonnet and raise each carburettor lift pin in turn. What happens to the idle speed when you do this?
You will find the lift pins at the rear of each carburettor, you will see a little pin with a spring around it. Pushing the pin raises the piston which will give an indication of how close or how far out the idle mixture is for each carburettor. Now this applies to HIF6 carbs, if you have HS6 carbs I cannot be certain if there is indeed a lift pin on that model. In which case if there is not, you will need to detach the elbows from each carburettor and then using a large flat bladed screw driver, very gently raise each piston only a mm or two and listen to the idle speed as you do this. What happens?
Ron.
So Phil, the idle speed drops right down and the engine almost stalls? If so then that indicates the idle mixture is too lean. Ideally you want the idle to lift slightly and then settle pretty much back where it was prior to raising each pin in turn.
Ron.
Ron.
That sounds about right then. The idle will be rougher to a point, all depends on how well everything has been set up.
Best bet is to tell him what it is now doing...that it did not do before and have him correct the problem.
Ron.
Best bet is to tell him what it is now doing...that it did not do before and have him correct the problem.
Ron.
Pilkie
Active Member
SU carbs are well known for having to run slightly rich on tickover to run well at driving rpm,especially taking into account years of wear.
I had the same problem on mine,and I tweaked the mixture "rich" by 1/4 turn of the adjust screw on hif6 or by 1 hex flat on hs carbs,till it ran right!!
I just had to turn the tickover down a tad after.
I had the same problem on mine,and I tweaked the mixture "rich" by 1/4 turn of the adjust screw on hif6 or by 1 hex flat on hs carbs,till it ran right!!
I just had to turn the tickover down a tad after.
