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MG MG Y Type - Engine cutting out

Help!

I know that this subject has been aired before, and I have contributed to the discussion. But I am completely baffled by the engine on my YB cutting out. On the last three occasions that I have taken the car out, most recently this afternoon, it has suddenly died after 8-10 miles and refused to re-start immediately, although it always has after allowing it to stand for an hour or so.

I certainly does not appear to be excessive heat - even in the spring-like weather today, the outside temperature is only about 8 deg C. I tried a new coil and connected a new condenser across the points, but to no avail. The fuel pump appears to be working - it ticks if I depress the float tickler.

I eventually managed to get it re-started this afternoon by pulling the choke out while cranking the engine - hardly normal for a warm-hot engine - and drove home over the same route with no problems.

I am getting worried because the car is scheduled as bridal transport for my daughter's wedding at the beginning of April and a similar unscheduled stop would be a disaster. Can anyone offer any suggestions as to the cause of this problem?

Mike Long
M Long

Hi Mike

Hot spotting, though more prevalent in summer is less about ambient weather temperatures and more about the lower boiling and ignition point of gas.

I am no tribologist or whatever the equivalent is in gas but I think the modern mix of ethonol has lowered the evaporation point of gas and therefore may be contributing to your problem. A heat shield and insulation blocks (those used on MG Midget/AH Sprite are just the ticket) will assist in lessening hot spotting.

Also, is the gas in your tank new or from last season? I had a heck of a job starting my MGB that has been sat for 6 months. I pumped out the old gas into a can, put it in my modern rig mixed 50/50 old gas/new gas and burned it off by use. Put new fresh gas in and once it was cycled through into the float bowls - it runs great.

Paul
Paul Barrow

Mike,
This may not be the answer but my YA began cutting out on the Brittany tour last year, which I put down to hot weather and vapour lock. I found it was happening because the fuel line was disintegrating because the petrol was attacking the rubber hose. Neil Cairns gave me some ethanol proof fuel line and it cured the problem.
Peter
P S Sharp

That is a good idea too Peter - hadnt thought about the effect this stuff has on our seals.

Mike - check the float bowls and filter screen on the float bowl inlet.

Paul
Paul Barrow

Hi mike,sorry to hear aout your problem,back in the early sixties I had an old morris minor, they also had an electric pump,I too had this problem, the dam car kept on cutting out about every 10 or 12 miles or so. It would not start for about 10 or 15 minuites or so, I replaced plugs, points, coil,ect, etc.I could not get to the bottom of it,I too checked fuel lines, etc. It accurred to me that it might be the vent pipe at the fuel tank blocked with dirt etc, and could be causing a vacume inside the tank as the tank emptied,I started to clutch at all manner of straws,anyway,the pipe was indeed blocked with debry so I cleaned it out and thought that was that! but no it was not.As a last resort I removed the fuel tank from the car and emptied the contents into a bowl and low and behold out came rust,and a peice of papper the size of a 50p the mind boggles as to how the papper got there in the first place,but that was the cause .I,m not saying that is your problem,but I too lost confidence in the car. the times me and my mate had to push the bloody thing home then blow me it would start first time,(one can only think it was because the papper had moved from over the fuel out let hole inside the tank.Best of luck with your problem Don.
d walker

Thanks to all who bothered to reply.

I remembered while watching TV the other evening ( I cannot remember much about the programme!) that many years ago, I had a similar problem with a Hillman Imp. I eventually found the cause when it happened at night. While trying to re-start it from under the bonnet, I noticed sparks from the distributor cap, which turned out to have a hairline crack. So, I have replaced the distributor cap and also the condenser, and cleaned the points.

As Paul suggested, I then checked the carburetter and found some silt in the float chamber. I cleaned this and blew through the fuel passages with an air gun. I then cleaned the filters on both the carb and the fuel pump. Paul, it is not the fuel hose as I have a newish one from Burlen, claimed to be resistant to modern fuels.

I then drained the fuel tank and flushed it through as well as I can with the tank in situ. I found nothing untoward there, not even paper! I had hoped to find some water, but not so. I put about 1 gallon of petrol back in the tank and the engine started easily. I will dilute the fuel with some new tomorrow and take the car for a run with fingers crossed.

Thanks again.

Mike
M Long

I have posted this before. This problem occured on 3 cars My MG YA MG TF and Ford 105e Anglia and each time was due to the hotter burning fuel expanding the exhaust valves so that they didnt quite close. The valves clearances listed in the manual were I think correct for the burn heat of the fuel then available. Clearly it may also be due to other factors ie rotor arm or distributer cap etc but this result I found from many hours at the side of the road scratching my head ! Bryan
B Mellem

Bryan,

I think with modern fuels you can have the problems you have with hot exhaust valves. My engine also ran rough when hot and adjusting the valves cured it.

Advancing the static ignition timing by 5 degr. BDC (instead of 0 degr. as per the factory recommendation) should have a positive effect on it. The fuel will start burning earlier so the exhaust will be less hot as a result.

What timing do you use on your cars?
Willem vd Veer

This thread was discussed between 16/02/2013 and 21/02/2013

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