MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGB Technical - 1966 MGB Cold Start Problem

Hello!

I have recently bought a restored 1966 MGB. I have had major problems getting it started. The starter motor turns over the main engine quickly, yet it just will not fire. The car finally tends to fire up after 3-5 minutes of turning the ignition. As you can imagine this is quite frustrating!! Any help would be greatly appreciated!! Is there a particular knack to starting the car that I don't know yet?

Thanks,

Darren.

PS - The condensor has recently been replaced and the engine has four new sparkplugs.
Darren

Even in Australia I suspect some choke will be required to start, is the choke mechanism functioning? As a general rule when aquiring an MGB you should check the valve clearances, plug gaps, points dwell, timing, and setup the carbs from scratch. Any MGB should be an easy starter, hot or cold. If it isn't something is wrong. For an engine to run you need air and fuel in the right quantities and compression and spark in the right order at the right time. For a non-starter I would check with a timing light (the 12v type with inductive pickup) that I am getting a flash during cranking on the coil lead and each plug lead. This is a good diagnostic tool and can reveal most ignition sproblems, even breaking down plugs. This will also allow you to check the timing, about 10 degrees BTDC should allow any engine to start even if it isn't the ideal value for that specific engine number. Next I'd check the plugs after cranking for a bit - no fuel smell means no fuel, soaking wet means flooded which could be an over-rich mixture or no spark, you should have a strong fuel smell but not soaked. Generally if you have flooded the engine you can smell it from inside the cockpit. If no fuel smell on the plugs is the fuel pump working?

But if it eventually does start I'd suspect a weak mixture i.e. no choke, the continual cranking and compressions eventually warming the cylinders enough to fire, which is bad news for the battery and starter.
Paul Hunt

I recently replaced the rear carb jet and had a similar problem. While the carbs were balanced and the mixture was about right I had been in a hurry and did not check out the choke. The result was only the front carb was choking and it was not enough to start the engine. Assuming that all else is correct, (carbs had been balanced for running off choke and that the points/timing are correct) check that both carbs engage the choke at the same time. I usually pull out the choke until the engine is running at about 2500 rpm's. At that point I balance the carbs using only the choke adjustment screw. Don't change the mixture or the idle screw. This is only a choke adjustment. After that the car should start when cold on choke.
Jim Lema

Yup! sure sounds like the choke.

Be a little more forceful when pulling on the the knob. And/or, follow the cable to the carbs and take out any cable slack.
glg

Darren,

I also own a 66 MGB that used to have a mind of it's own when it came to starting. All responses so far advise of the need to choke the carbs on starting. Good advice as that certainly is the case with mine. If I don't choke, I wonder if it would ever start. That is when its cold, even in the summer. So that certainly is a factor to consider. After choking, heavy choking I might add, the car will run well, even under load, at no choke in one minute.

You did state that you purchased a "restored" 66 B. Based on that I assume it has new plugs, ignition wires and tune up goodies, and the carbs have been set up and balanced. If so the choking advice is on the mark, if not, then Paul Hunts advice is very sound, as these items need to be in order for the choking to be of any use. My car has a stock 25D distributor and prior to distributor rebuild, that spark would float around a bit. Also I found that good solid ignition plug, wires and connections are a must and often can be the root of some of this cantankerus starting.

Let us know how you do with a little more on that choke knob!

Jim
Jim Hanks

The choke is not being fully engaged. Adfjusting this so it is fully closed will fix this problem
Russell Read

This thread was discussed between 24/10/2003 and 29/10/2003

MG MGB Technical index

This thread is from the archive. The Live MG MGB Technical BBS is active now.