| Author | Message | ||
     Nick Brough Unregistered guest Posted From: 84.65.58.87 |
Hi, Having overcome my starting problems and a couple of short runs I took my 20/25 for an MOT with no problems. On the way back (after about 35 trouble free miles) she began to run roughly. Inspecting the plugs they were black, the mixture setting was mid way. Since then she seems to be running rich with a loss of smoothness. Any ideas as to why all was ok and then this. Thanks Nick (Message approved by david_gore) | ||
| Robert Wort Grand Master Username: robert_wort Post Number: 135 Registered: 12-2004 |
Hi Nick, From memory I seem to recall that the 20/25 hp had an Autovac fuel delivery system. if this is the case,you may need to dismantle it and check for gunge and perished diaphragms and seals. It's been a hellavu long time since I've been near one so I might have to see if I can find the necessary doc's from some of my old collection. One of the failures with this system was that after motoring at relatively high speeds (for a 20/25hp that is), fuel starvation could occur. This is obviously not the case with yours but it might be syphoning too much fuel into the carburettor. In any case, I would have a good look at it. | ||
| Stephe Boddice New User Username: stephe_boddice Post Number: 2 Registered: 2-2005 |
Nick, It is worth checking the Autovac for cleanliness, as suggested by Robert, although this will not cause a rich mixture; the float chamber inlet valve would see to that. A sudden change to rich running can be caused by several wierd occurences on these engines. As a start, check the following: - 1) Check that the choke (cold-start carburettor) return spring has not snapped or become disconnected. 2) Check the float chamber inlet valve and make sure that it is not sticking or jammed with a piece of grit/dirt. A simple job - flick off the locking catch and unscrew the lid of the chamber. While you are in there it is worth checking the float setting - see handbook. 3) It depends on the series of engine for the following. Earlier cars did not have an air filter; just an inlet tract with a fine gauze filter sheet inside. If of the earlier type, check that the filter is there and, if so, make sure that it is not blocked. If of later, full filter type, check that the filter is clean and not blocked. 4) Unscrew the jet assembly from the top of the carb. (the big knurled cylinder on the top of the carb). Wipe the valve and venturi clean with a lint-free cloth soaked in pertol or paraffin. Do NOT attempt to use a metal polish, or similar, as this will really cause damage to the carb. Make sure that you do not loose the large aluminium sealing washer. If necessary, dismantle the air jet and clean inside. Again, all instructions are in the handbook but if you don't have one let me know and I will copy you the relevant bits. 5) Check that the pinch screws on the carb levers are tight. It is not unknown for these to come loose and alter the tickover and mixture settings. And finally - 6) Make sure that the steering wheel mixture lever was not left on 'strong'. Let us know the outcome, please. Stephe Boddice (GB) 20/25 - GGA27 www.boddice.co.uk | ||
| Robert Wort Grand Master Username: robert_wort Post Number: 136 Registered: 12-2004 |
Thanks Stephe, I knew someone would be better able to answer Nick's question and my knowledge is only perfunctory being that it has been at least twenty years since I played with a friend's one. By the way Nick, Being that you also own a Brough Superior Motorcar, I was wondering whether your last name was a coincidence or whether there was a family connection? | ||
| Nick Brough Unregistered guest Posted From: 84.66.47.226 |
Hi Thanks for the advice, i had already cleaned out the main dashboard filter I willtry the other things. Robert I think I may be related as there are not many Brough's around and my dad wasborn in Uttoxeter which is not far from Nottingham. i prefer to think I am related than to go looking and find I'm not. Nick (Message approved by david_gore) | ||
| Robert Wort Grand Master Username: robert_wort Post Number: 159 Registered: 12-2004 |
Makes perfect sense to me Nick. Why spoil a good pickup line eh?  | ||
| Nick Brough Unregistered guest Posted From: 84.64.107.227 |
Hi, I'm back, things on the starting front got better for a while although the plugs still seem to foul up on occasions. Now the problem is back is this a winter thing? I have found that after a bit of cranking on the first attempted start of the day, if I then stop undo the float chamber (first did this to check for fuel) petrol pours out the top, screw the float chamber top back on, get back in car she will start first time. There will then be no starting problems for the rest of the day. This appears to happen every time I go through the process. Any ideas about this strange behaviour. Regards Nick (Message approved by david_gore) | ||
| Stephe Boddice Experienced User Username: stephe_boddice Post Number: 38 Registered: 2-2005 |
Nick, As you have come back after a year's lay-off may I suggest that you register? The only difference is that the poor old moderators do not have to vet your postings every time you visit the board. Addressing you current problem - it sounds normal to me. I assume that there is a gap of at least several days between using the car? If this happens on consecutive days then I would suggest that there is a small fuel leak from the base of the float chamber. When you leave the car for any length of time the fuel evaporates from the float chamber. My starting procedure is: - 1) Fuel tap on 2) Battery on 3) Crank engine with the ignition off for about 10 seconds. This is usually enough to cycle the Autovac and draw fuel from the tank. You should hear the Autovac valve clicking in and out. 4) Wait 20 seconds for the fuel to drain into the carb. 5) Ignition and choke on 6) Press the starter button and the engine should start straight away. When you switch off the engine make sure you close the fuel tap, othewise, if you do have a slight leak it will drain the carb, filter and Autovac. SB | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 536 Registered: 9-2004 |
Just a thought,Is the starting on the starting carb ok once it fires or does it stop on this before normal running. Nick off subject is the Brough like this.  | ||
| Nick Brough Unregistered guest Posted From: 81.77.165.31 |
Hi Patrick, Thanks for the advice I will register. I will try what you suggest I have not been using the starting carb as she seams to start straight away as soon as petrol gets through. But I do have problems after just one day. I tried filling the float bowl with fuel first but that did not seem to work. The picture certainly looks familiar only the paint looks much better than mine. Is she an eight cylinder and where is she I know about most of them but this may be a new one. Mine was at the Yeovil festival of transport a couple of years ago as I used to live in Beaminster before being forced North. My mum still lives in Axminster. Regards Nick (Message approved by david_gore) |
