My 3.5 carburetted RRC has developed an aggravating habit.
Under no load it will rev to infinity quite happily, but under load it wil cough and fart and splutter its way down the street and when it's running more or less as it should it starts behaving like it's running against a
We had something similar on our V8 90 with SU's on. the first time it was a bit of muck in one of the carbs the second time was a droplet of water. Richard
Check ignition system first, 'cause it's easier, especially check the condenser and coil. Look for a clear sharp blue spark at the plugs. Then, clean and/or replace any fuel filters, my 90 has one on the pump in the fuel tank and another after it, if this doesn't cure it and you find any muck in the filters then strip and clean your carbs making sure the float chambers and jets are clean. Finally, some silly things, make sure the tank isn't negative pressurising and the breather is working and that your exhaust is not blocked.
Maybe a stuck piston. Take the three screws out (carefully so as not to drop any), then lift the top off the carb. Remove the piston - the big roundy thing that's under the cover - it'll have a needle on the end - try not to damage this :-)
Clean the piston, put it back.
You'll probably then find the cause was something completely different, but at least you'll know how to pop the top of a carb when you need to :-)
Pull off the 180 degree elbows that go onto the carbs and you should be able to see the fuel going in and feel the suction. You'll soon see which carb you have to pull apart if it's a single carb issue. (note: I'm not responsible if your pet hamster is sucked in...:)
Check every thing from spark to fuel. If you do need parts for the carbs doble check that they are SU because I thought they would be Stromberg for a vehicle of that age. Regards
One thought I am now having is that I *may* have managed to get water into the fuel tank. I went on SimonKs nice offroading trip to Cannock Chase and as anybody following me would tell you my fuel cap seal is shot. At one point I did take the car wading and I can easily imagine getting water into the tank at that point.
Now you mention it Dad had similar problems on an ex-police Rangie of 1976 circa... the problem then was the filter in the tank. Given you've had a good old sploosh around any muck in the tank may have been dislodged and found a new home in the end of the filter. Standard practice is to remove this PITA filter, extend the pipe and if necessary refit another in line filter under the bonnet...but to be honest one less filter won't hurt unless you have real big crud in the tanks.
I've now taken it out, put around 1/4 tank of fuel in it and taken it for a hard run.
I'm now leaning towards it being a poor spark as when revved hard (40 in 2nd on a 4 speed manual) enough petrol is getting into the exhause to cause pops and the occasional backfire.
I'll check the plugs later, but I expect to find them sooted up badly or possibly oiled. I've got a Colourtune here I'll try it on and see what I get, but I now have a course of action to follow.
Thanks to everybody on this one. Turns out that the carbs (Solex licensed Strombergs) were fine, however my local garage (Redline Services of Aylesbury - recommend them) did replace the points for me, reset the points and reset the timing along with replacing the air heater hose.
The really embarrassing thing about this was that when I replaced the old leads with Luminitions I must have been crosseyed. They tell me that the entire odd numbered cylinder bank was miswired and they're trying to figure out how the hell I got the car to them.
It's running sweet as a nut now - better than at any time since I got it. The Luminitions and Super4s seem to have made some difference after all.
Next trick is to get my backside to the proximity of a heater matrix and replace that.
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