engine suddenly runs rough

[rogerb]

I have just shipped my moggie to the states. Before it was shipped it was running almost perfect. The best for a very long time. On arrival I started her in the container first go ( ok it wasn't instant but it had been in there for 5 weeks) and drove her into her new garage. Next trip was about 2 weeks later and again she drove really well. Next trip about a week later and it was reluctant to start, coughed and spluttered when driving. Once going it would pull ok, but died at each stop. Reluctant to start each time. Nursed her back home. Today changed the rotor arm and dissy cap as they looked a bit iffy. Tried to start her and the battery went flat after a couple of goes.
I do not think it is the different fuel as I put a higher octane in to counter the difference. I am confused as to why it was perfect one time and rough as anything next time. I have checked the vacuum pipe from auto-advance to the carb and that is fitted ok.

Any thoughts as to this sudden deterioration and the flat battery, is there a connection between the two?

[Jefftav]

What about the filter in the bottom of the pump as with shipping etc crud may have got disturbed and collected in the filter? It might also be worth cleaning the carb and if the carb is getting fuel then investigate the points, and condition of the distributor, plug leads etc..

I am also assuming the engine isn't getting hot as fuel vapourisation can sometimes be an issue with exhaust sitting under the carb and still on that theme has the engine been overheated as the cylinder head gasket could have gone. Thats thinking worst case scenario though it is likeley the be something simple and you just need to work through the fuel and ignition systems to find the fault.

[GBond]

I'd drain the fuel tank, 5 weeks in a very salty/humid environment is probably not good for the fuel.

Also, reset the points gap and timing to known good settings.

One more thing to consider would be altitude, if it's very different from where you were before you'll probably need a leaner/richer mixture.

[bmcecosse]

Surely you had to completely drain the fuel tank for shipping?? So as above - good advice - check for fuel flow.. When you changed the cap and rotor - are you sure the rotor is the correct one/fitted correctly - and the plug leads are all back on as before - correct order ?

[Nickol]

Check the air filter too

[rogerb]

Thanks for your input, still not fixed but here is update.
I have changed the plugs, dissy cap, rotor arm and HT leads. Cleaned the points and rest the gap. Unblocked the blocked vacuum pipe between the distributor and the carburettor. Dismantled the carb to check the float was working and that there was no gunge in the bowl. Checked the in line fuel filter for blockage and debris. After reassembly it is exactly the same! It will start on quite a lot of choke and run at a high speed ok, but as soon as the revs drop and just a little accelerator application it coughs splutters and 'backfires'.
Any further ideas before I strip the distributer down? My thoughts now are that the advanced and restart mechanism is stuck in the advanced position.

Roger

[bmcecosse]

Are you SURE the spark plug leads are on correct order? 1342 anti clock around the dizzy. This seems the most likely explanation. Otherwise - blown head gasket...although why now is certainly a wonder. A compression test will reveal all....

[katy]

Ditto on the compression test.

[rogerb]

Hello again
I have double checked the plug leads and they are definitely in the right order.
I did a compression check and they were all around the 140 mark.

I contacted my normal supplier, Birmingham Morris Minor centre (David Manners group it is called now) and they could supply a replacement vacuum unit, but when we got talking, a complete distributer (a 45D) was only 29.50. So I now have one of these complete with cap, rotor arm etc. Amazingly it only took 3 days to get to me in the USA. I have fitted it and I think it will fix the problem. The only thing is I am guessing at the timing settings. I did have a look before I removed the old one and have tried to set it up same as, but of course it is not!

So my next question is what should the settings be on a 1275 Midget engine, with a 45D distributor, a 1 3/4 SU, Healy(?)heated inlet manifold and a LCB exhaust manifold. There are 3 timing pointers on the bottom of the engine and one notch on the crankshaft pulley.

I have tried to set it so the notch lines up with the middle pointer when No 1 piston is at the top of its stroke as observed by looking into and feeling (gently with a long screwdriver)the plug hole. It starts but it is not right. Just a little bit out of adjustment, but which way and how do I know when it is right? Had to stop tonight as the battery has gone flat (I do not have a starting handle anymore unfortunately) and the boss called me in for dinner!

Roger

[bmcecosse]

Just start it and turn the dizzy gently back and forth to get the smoothest idle. Get it warmed up before you settle on the final smooth setting and clamp it down.