2A Power Loss

[HowardSmall]

My 2.25 petrol ex-army S2A was running fine then suddenly lost power. It starts OK but has no power under load. It has a new Fuel pump, spark is fine and I have fitted a rebuild kit to the Carby all to no avail.

I am wondering if the accelerating pump assembly could be the cause? Any suggestions welcome.

Howard

[JDNSW]

Firstly, this thread is in the Holden powered Landrover section but you are not talking about a Holden engine. Should ask a moderator to move it.

Accelerator pump not working will not explain loss of power, it will explain poor acceleration when the throttle is opened suddenly.

As I understand it, it is starting readily but no power under load.

A few things to check

Is it running too rich due to flooding - will get worse as the engine warms up, expect black smoke.

You say the spark is fine, but check condition and gap of points, and other possibility is weak coil or faulty HT leads. Also, low voltage at the primary due to a poor connection somewhere. Check the voltage at the coil both with points closed and open. And check spark plugs. I have seen exactly these symptoms from points closed up.

Fuel starvation. This could be either a partial blockage or an air leak in the fuel line or strainer - most likely suspect is the pickup tube in the tank. Can also result from the fuel pump having a bit of dirt under a valve.

Ignition timing. The distributor may have moved, changing the timing, or the centrifugal advance may be stuck, or the vacuum advance may be faulty or its vacuum line leaking or disconnected. In a slightly different class, plug leads on wrong plugs.

Vacuum leak, either below the carby, the PCV if fitted, or a loose manifold. Usually results in really hard starting though.

Loss of compression. Usually develops slowly if it affects all cylinders and if not causes rough running as well as power loss. Rough check by turning over with the starting crankhandle.

Hope this helps

John

[HowardSmall]

Well we checked everything - did a carbie rebuild, checked the fuel pump and lines, changed the plugs, re-checked the points, checked spark, changed the condenser, etc, etc. Finally found the cause - the timing was way off!

How can it be that over three days the S2A did the CREB track, a day around Cooktown, next day the Bloomfield track and about 60km from home it suddenly loses power and has to be towed home because the timing is massively out?

This was great fun to trouble shoot...

Howard

[JDNSW]

I assume you mean the ignition timing - presumably the distributor moved because the clamp bolt was not tightened enough.

John

[HowardSmall]

Hi John

It was tight but it looks as if:

A. the distributor is 180 degrees out of alignment
B. vacuum retard operated and it then jammed

To confirm the 180 degrees theory, should the plug lead connected to the distributor closest to the front of the car be cylinder 1 or 4?

Howard

[JDNSW]

Hi John

It was tight but it looks as if:

A. the distributor is 180 degrees out of alignment
B. vacuum retard operated and it then jammed

To confirm the 180 degrees theory, should the plug lead connected to the distributor closest to the front of the car be cylinder 1 or 4?

Howard
On mine the front one is No.1. I did not think it was possible to install the distributor 180? out. But it may be possible to get the drive shaft from the pump out!

John

[HowardSmall]

Well it was all running 100% so I decided to drive it home. I got about 20km and power was lost!

Lucky I was near a fellow RFB volunteers house so I limped about 25 yards into his drive.

Turns out he is a mechanic having done his apprenticeship on land rover series 2. He checked it all out, set the timing and had it running perfectly. Out on to the highway I went and got about 400 yards before - power loss! Took me about 40 minutes to limp it back to his place. To do that I had to let it sit for a while, then start it and drive at low revs in first gear. After a while it would give up, no power, bad back firing - blew oil out of the air filter.

It is now sitting at his place until Tuesday when we can have another crack at it.

Anyone have any ideas? Things to check?

Howard

[JDNSW]

Still sounds like an ignition issue. Is the centrifugal advance mechanism sticking?

John

[HowardSmall]

Sounds like a possible cause. If one of the springs on the centrifugal advance is broken could that be a cause? I can't check it out until next week when I can get to the property it is on. In the meantime I am trying to get my hands on another distributor as this is looking like the only thing left...

Howard

[ian4002000]

Sounds to me its got a fuel delivery problem and is running lean.
could be something floating around in the tank blocking the pickup pipe or a worn out fuel pump.
Take the pipe off the carby and turn the engine over fuel should pump out.
if it does it may be a sticking needle and seat, if not go back through the fuel system until you find a problem.

[cookey]

Sounds to me its got a fuel delivery problem and is running lean.
could be something floating around in the tank blocking the pickup pipe or a worn out fuel pump.
Take the pipe off the carby and turn the engine over fuel should pump out.
if it does it may be a sticking needle and seat, if not go back through the fuel system until you find a problem.

I agree with Ian....sounds like lack of fuel

cookey

[HowardSmall]

Thanks for the thoughts guys. We have pretty well eliminated the fuel - rebuilt the carbie, new fuel pump, cleaned lines from both tanks, cleaned the tank selection tap, seen fuel pump ok.

Have spent hours working on it and the only thing we haven't done is disassemble the distributor which is scheduled for Tuesday. Hopefully on Wednesday I can post some good news.

Howard

[chazza]

Problems like this can be so hard to diagnose from a distance especially when it could be in the fuel; ignition; or valve-timing dept.

Just in case it is something blocking the main jet, an easy way to eliminate it, or prove it, is to run the engine whilst it is playing-up and then pull the choke/fuel enrichment device on.

If the jet is clear the engine will run worse and flood; if it is blocked the richer mixture will cause the engine to behave almost normally.

I have had this happen to me at least twice on two different vehicles. Use high pressure air and wear eye protection when blowing out every orifice in the carburettor,

Cheers Charlie

[HowardSmall]

Replaced the distributor today and all runs fine now. Looks like the centrifugal advance failed.

Howard

[JDNSW]

Thanks for letting us know.

Another possibility (still distributor) is that the top bush of the distributor has failed so the cam has considerable sideways movement so that the set points gap bears no relation to the effective gap once the engine is running. Although I think your symptoms sound more like the failed centrifugal weight spring.

John