Cutting out on acceleration

[gatsby989]

Greetings all,

I'm having a problem with my 948 Minor cutting out when accelerating. It had been running fine, and I took a drive including a climb up a decent little hill. It was warm that day, and climbing that hill it started cutting out. I eventually made it, and managed to get back home, but barely.

The car will start and idle fine, accelerate in first gear and I can go slowly around the block, etc., with everything seeming fine. However, once I start accelerating in second gear, the engine cuts out and will just die. It will fire right back up again, but I have to go real slow in first or second.

I have an electronic facet fuel pump which seems to be working fine. No loud ticking from it (as it does when it can't pressurize).

I've tried regapping and cleaning the points, and replaced the condensor, to no effect. I haven't fiddled with anything else except pulled the spark plugs and had a look. The outside rim is black, but they are dry and the nose and lead are biscuit colored.

Any ideas? Thanks very much.

[aupickup]

check dashpot oil in thr carb

[gatsby989]

There's oil in the dashpot. Maybe too much? I know there's lots of debate about the right oil to use. I believe it's just engine oil in there now (30w). I could try syringing it out and replacing it with 3in1 oil

[bmcecosse]

Sounds like petrol supply problem to me. Test the pump flow into a container.

[gatsby989]

Well, replacing the dashpot oil with 3 in 1 oil has made a substantial improvement. In fact, it seems to be running normally now. But now I'm a little perplexed. The trouble started a few weeks ago and I don't remember if I had tinkered with the dashpot oil or not then. I must have done something.

[simmitc]

Try checking:

• The vacuum advance
  Petrol flow rate (at least 2 pints per minute)
  Piston in carb free to rise and fall
  Jet in carb not blocked
  Air filter clean

[bmcecosse]

Heavier oil usually makes for more steady performance. Thin oil can cause 'gasping' although my ultimately give better performance is the carb is set slightly rich.

[katy]

May be running a bit lean.