Thread: Hot engine won't start

Well, to answer Aarons's question about good spark I made my own 'spark tester' (with 10mm gap) to let me see what was going on when I cranked the motor. The spark was NOT good after all! It seems the condenser I found was not as suitable as I thought so I put the old one back in and the spark was much improved. However this hasn't helped the starting/running problem which continues to mystify me. The carburettor now seems to drizzle fuel continually from the small copper inverted 'U' pipe. The engine will now start from cold with no choke and will idle okay for a while but if I try to rev it it dies after 30 seconds or so and I can't restart it. While idling the exhaust spits black smuts and the plugs become blackened. I visited Repco to get some fibre washers to relace the ones in the dripping fuel union. With new washers it now leaks like a sieve! I just don't get it...

Originally Posted by JDNSW

Choke on this carbie is an "enrichment device" - opens up an extra jet. From memory it has only two stages -i.e. it is not progressive. The inability to adjust the idling suggests the mixture is too rich beyond the range of adjustment to compensate. This may be because of internal leaks in the carburetter or because the petrol level is too high (worn needle and seat of leaky float) or possibly excessive fuel pressure . Sounds as if it could do with an overhaul. But the ignition problems you have indicated could be enough to cause your problems.

John

I was going to say the same thing, but add that a low bowl level, plus crap in the bottom of the bowl.
With the fuel pump, do you have a return line to the tank or is it just one line with no return???
If you have an electric pump, you should have a return with some kind of minor restriction, back to the tank. It could be that the pump is flooding the bowl also.

Originally Posted by LOVEMYRANGIE

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If you have an electric pump, you should have a return with some kind of minor restriction, back to the tank. It could be that the pump is flooding the bowl also.

The original SU pump did not have a return line (they give a fixed pressure regardless of flow rate), so this does not apply to all electric pumps. If fitted with the original SU, or a near copy, there should be no problem. But if it is another type of electric pump, then there is a very good chance that the pressure is excessive (the persistent leak from the fuel inlet to the carburetter certainly supports this).

The ideal thing would be to fit a more suitable pump. I can't find delivery pressure data - probably because it is fixed by the spring in the pump, not adjustable, and never a problem! But it would help when assessing whether it is a problem. It is worth noting that the SU pump was always installed close to the carburetter and at about the same height, but many more modern electric pumps are designed to be installed close to the fuel tank, and hence need to deliver higher pressure. Installing them where the SU was may well cause problems from excessive pressure.

John

I support the idea of excessive fuel pressure, or leaking needle and seat. This would give the symptoms provided. My SU failed, so temporarily I have installed a Facet electric pump. This does not flood the carburettor. It is in the SU pump position. I would suggest that you clean and kit the carburettor. It makes a huge improvement.

Aaron.

Originally Posted by DiscoDave

Well, to answer Aarons's question about good spark I made my own 'spark tester' (with 10mm gap) to let me see what was going on when I cranked the motor.

Make it a little bit exciting. Insert a two inch piece of fencing wire into the plug lead end. Hold the lead a bit back from the end. Two or three inches is fine. Start the engine, and experiment to see how long you can get the spark. Much more interesting. You should not get a shock if you only touch the insulated part of the lead. These old systems (conventional coils) only provide a modest spark when compared to the modern electronic ignition coil packs, like on commodores without distributors.

Aaron.

Originally Posted by DiscoDave

I visited Repco to get some fibre washers to relace the ones in the dripping fuel union. With new washers it now leaks like a sieve! I just don't get it...

Buy a set of hole punches. The type that you hit the top of with a hammer. Get a sheet of gasket paper. It comes in various thicknesses. You should be able to buy a small sheet (a dollar or two) or by the meter. Then cut your own fibre gaskets. If it still leaks, put on two or three to build up the thickness.

Aaron.

People haven’t heard of inbuilt ballast resistors. This may be the wrong way to describe the difference between coils that are built to have an external resistor and ones that don’t due to higher internal resistance if so I am sorry but every one I have ever spoken to refers to them as internal or external.
To make sure I am not confusing people I will explain what I was talking about. This only refers to early English cars such as S1 Land Rovers and Minis etc.
As an example of a car that uses an external resistor let use a Holden Red motor, the resistance is built into the wiring, so that when stating the full battery voltage is applied to the coil and when you release the key back to on the coil is supplied thought the external resister and as someone stated probably around 9V. This improves starting.
If you run a coil that needs an external ballast resistor on a S1 the coil will run very hot thus its life is shortened and they can intermittently break down.
I used the Bosch GT40 as an example as it is the only one still available that I know of and is commonly stocked, as a reference it even states Series 1 Land Rover on the packet. Remember this coil also comes in two other formats GT40R and GT40RT that do not suit early English cars. You may still be able to get Lucas but I don’t know where and the GT40 packs a good punch. You need to paint it to get rid of the orange/red colour not very English.
A quick Google of automotive coils will confirm what I stated or talk to your friendly auto elec, if he is over 40. Feel your S1 coil after a 20 K drive if it takes your skin off it is the wrong one.
Sorry if my first post confused people but this is a common mistake and I have burnt my hand on more than one series Land Rover due to it having the wrong coil

Originally Posted by dennisS1

People haven’t heard of inbuilt ballast resistors. This may be the wrong way to describe the difference between coils that are built to have an external resistor and ones that don’t due to higher internal resistance if so I am sorry but every one I have ever spoken to refers to them as internal or external.
To make sure I am not confusing people I will explain what I was talking about. This only refers to early English cars such as S1 Land Rovers and Minis etc.
As an example of a car that uses an external resistor let use a Holden Red motor, the resistance is built into the wiring, so that when stating the full battery voltage is applied to the coil and when you release the key back to on the coil is supplied thought the external resister and as someone stated probably around 9V. This improves starting.
If you run a coil that needs an external ballast resistor on a S1 the coil will run very hot thus its life is shortened and they can intermittently break down.
I used the Bosch GT40 as an example as it is the only one still available that I know of and is commonly stocked, as a reference it even states Series 1 Land Rover on the packet. Remember this coil also comes in two other formats GT40R and GT40RT that do not suit early English cars. You may still be able to get Lucas but I don’t know where and the GT40 packs a good punch. You need to paint it to get rid of the orange/red colour not very English.
A quick Google of automotive coils will confirm what I stated or talk to your friendly auto elec, if he is over 40. Feel your S1 coil after a 20 K drive if it takes your skin off it is the wrong one.
Sorry if my first post confused people but this is a common mistake and I have burnt my hand on more than one series Land Rover due to it having the wrong coil

You are right - there are two kinds of coil, those designed for a (external) ballast resistor and those that are designed to run directly on 12v. But these do not have an internal ballast resistor - they simply use thinner wire on the primary and are designed to not overheat on 12v. (sometimes described as a 8v coil or a 12v coil) One thing that should be added is that the external ballast resistor on many vehicles is not a discreet component, but is simply the wire from the main harness to the coil - not recognising this and replacing it with ordinary wire is a favourite way of killing the coil.

I cannot think of any post war English engine that uses a ballasted coil except perhaps for US derived engines (I have an idea that some Rover V8s do, for example)


And using the wrong coil will always give trouble - use a 12v coil with a ballast resistor, and you will get poor spark, and consequent poor performance. Use a 8v coil designed for use with a ballast directly on 12v, and you will end up with a cooked coil (although modern ones will survive quite a while) and burnt points, but you will have a really good spark while it lasts.

John