Difficulty starting after standing

Tom W

Tom W

Active Member
Hi all,

I've not used my Rover much recently, but when I have I've found it difficult to start after it's been left standing for a few weeks. It churns over for a while before eventually firing. Luckily the battery is good, so it will eventually fire. I first thought this was down to fuel draining from the float chambers, so tried pumping the fuel pump. I can feel and hear the carbs being filled and aventually the lever stops pumping so I guess the fuel pump is good. This doesn't make any difference to the cranking time though. The car always starts first time when warm, and starts promptly from cold if only left to stand overnight. It seems to run fine in all other circumstances too. The carburettors have been freshly rebuilt and balanced, but there may be more fine tuning to do on the choke linkage. Also, the cranking speed increases after the first few revolutions. I wonder if I have too thick an oil in there? I use millers classic 20w50, or perhaps there's a loose joint in the starter wiring who's resistance reduces as it heats up slightly?

Any suggestions as to where to look first? I may try adjusting/balancing the choke linkage first as I don't think it's giving enough fuel to match the extra air it gives.

All help greatly appreciated.

Tom
 
My 2200tc does this but priming the carbs cures it. I have a pump rebuild kit to fit but not got round to it yet. I believe valve clearances can cause poor starting.
 
I've not checked the valve clearances recently, so that could be a possibility. I'll have to borrow a friends dial gauge and check. The times I've tried with feeler gauges, I found the readings to be a bit hit and miss.
 
Thanks for that.

I assume I do this by setting the required idle speed by the book (I forget the figure) when the adjuster bolts match the little marks on the cams. Then check the airflow through the carbs and readjust as necessary to achieve balance. Then refit the air filter and readjust both screws at the same time to bring the idle back to the correct value. Presumably if my basic mixture settings are a little off, then this will throw the whole thing out. Should the engine be hot or cold when this setting is made?

I will try this first as and report back

Cheers, Tom
 
Settings should be done with the engine at normal running temperature after checking the ignition settings. With the chokes off (and the fast idle screws clear of the cam) set the idle speed, balance and mixture, then make sure both chokes are working fully and together. The fast idle screws should be set so that when the choke is operated the cam comes into contact with the fast idle screw when the line on the cam is in line with the centre of the head of the fast idle screw. If all the other settings are correct, and the fast idles are set like that, then the fast idle speed will be correct, regardless of what it says in the book.

PS. As far as the fast idle settings are concerned it doesn't matter whether they are set hot or cold.
 
That makes sense. I'm happy the normal running settings on the carbs and ignition are correct, so just the fast idle screws to adjust. I think I have them set a little too early at the moment i.e. the cam contacts the screw before the mark, meaning the mixture is a little lean at a sensible idle speed, hensen the difficulty starting. The car does require quite a high idle speed on first starting, hopefully this will correct this.

Cheers,

Tom
 
Hi Tom

Post back when you have made the adjustments. This is something I haven't checked on my car and would be interested in your results.

Pat
 
Well, I had a go at setting the choke mechanism today, as per Harvey's method. Open the choke until the little marks on the cams are beneath the centre of the fast idle screws. Loosen the locknuts and back off the screws. Gently wind the screws down until they contact the cams, then tighten the locknuts (I can't help thinking this would be easier with a screwdriver slot in the top of the screws). I also refitted the warm air feed duct from the exhaust manifold to the air box. This missing shouldn't affect initial starting, but would make a difference to the warm up.

Anyway, time for a test. I primed the fuel pump, pulled out the choke and cranked the engine. It did seem to crank over a bit quicker (possibly lower compression due to a smaller throttle opening?), and fired after a few seconds cranking. After backing the car out of the garage, I stopped it, then tried again. This time it fired instantly. The fast idle is now much lower, max about 1250rpm according to the tacho, so the engine doesn't try to race the moment it starts to fire. Initially it only ran on 3 cyl, but this might be an unrelated problem. As it warmed up, it found the 4th. The car had been standing about 4 days, I'll have to see what happens if it stands for longer. I may need to investigate setting up the engine stabiliser, and possibly new engine mounts as the engine jumps about a lot when starting from cold. I also need to check the throttle cable routing and linkage. I think something is sticking as the revs don't always return to the correct idle speed.

All in all though, a success. Many thanks for the help.

Tom
 
It's now been a couple of weeks since I adjusted the carburettor fast idle, and I've now had a chance to start the car from stone cold. First impressions are the idle speed and control on the choke are a lot better, but the engine still takes a lot of cranking before it will run. I believe the fuel pump diaphragm is good because I can feel it pumping fuel when I operate it manually. I can also feel a change in the action when the float bowls fill up. Also, the engine isn't running on all cylinders when it first starts. As it warms (30sec/1min or so), it settles down. This may be due to an ignition issue. The plugs are due a change so I will do that first before investigating further. I've noticed some dampness on the input pipe into the fuel filter which smells of petrol. The pipe is nipped up tightly though. Could a split in the pump diaphragm manifest itself as a leak here? I believe it's a fuel fault because when the key is first turned, the engine fires once (presumably on the residual fuel in the carbs) then it churns over until it eventually fires. Once it's started, even if only for a few seconds, it starts easily thereafter.

I think my next steps will be to replace the plugs and check the timing is still accurate. Hopefully this will cure the misfire, but should at least rule out ignition problems as the cause. Then I think I'll remove the fuel pump and strip it down to see what's going on inside. At the very least, I'll be able to investigate the slight petrol leak.

Any other thoughts?

Cheers, Tom
 
If it isn't running on all cylinders when it first starts then that definitely needs sorting, so run through all the normal suspects, and then see the result of that. I'd be inclined to leave the pump until this is sorted, otherwise if you do both at the same time and it cures it, you'll never be quite sure which one was actually the cause.
 
Tom W said:
I believe the fuel pump diaphragm is good because I can feel it pumping fuel when I operate it manually. I can also feel a change in the action when the float bowls fill up. Tom
Click to expand...

Tom this is how my 2200tc is on the priming handle and I have the same problem.

I think the output valve on the pump isn't sealing properly and petrol is leaking back from the carbs when the engine is switched off and left. If I leave the car a day without use its hard to start, less so when primed. Out and about it always starts first touch. Either way it always fires on all 4 so as Harvey says that needs sorting.

I also have the excessive fast idle after it catches like your's did, I limit it by quickly pushing in the choke before it goes too high. I'll add that adjustment to the endless jobs list! Thanks for the update very useful.
 
Thanks for the input.

When I next start it, I'll try disconnecting plug leads one at a time to see if I can identify which cylinders it's firing on. Just to clarify, what is the path for the fuel to the rear carburettor? The fuel pipe runs from the pump to the front of the front carb. The rear carb is fed from the pipe that links the two. Does the float chamber in the front carb have to be full before the rear carb gets any fuel?

Tom
 
Just found some info on the SU website which answers my questions about the flow of fuel into carbs and float chambers.
 
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