Esso petrol contaminated with water or stale petrol

[Matt_Harrington]

Evidently 'Esso Synergy Supreme+ 99' is  ethanol free and they sell it at the Tesco garage closest to me.

Don't shoot me if I am wrong ... just read about it on another forum.

Ash, I believe the Supreme fuel isn't available in Devon / Cornwall. I use this fuel whenever possible and confirm there is no ethanol in it (AFAIK)

[hondacb750fourk6]

Evidently 'Esso Synergy Supreme+ 99' is  ethanol free and they sell it at the Tesco garage closest to me.

Don't shoot me if I am wrong ... just read about it on another forum.

It’s a Rover 2.2 twin carbs with su carbs on it

[K2-K6]

Presumably a P6 then ?  A nice car and very interesting design too.

SU will ordinarily not be unusually sensitive to anything much in the way of minor fuel compromise. Unsure if you are experienced with them or new to you ?  Check the oil in carb dash pots if you've not already looked there.

Sounds more likely ignition if it's on points still.

[Bryanj]

Also check the rubber pipe between carbs i have seen one where slivers of rubber came off the inside when fitting and messed up float needles

[Martin6]

Any non metal fuel pipe, if not replaced with ethanol proof, will degrade. In some cases it dissolves and coats the carbs.

I have twin SUs on an old Triumph car. The carbs are fine with E10, but the fuel will go 'stale' after a few months. Very difficult to start and runs badly until new fuel gets through.

I always turn off the fuel tap on carburettor motorbikes and run the final half mile or so, to run them as dry as I can. I now know where to turn the taps on each bike, so I run out just as I'm home. At least it empties the jets and pilot circuit. Don't know if that works, but no problems so far after a number of years, having made sure they were clean to start with.

[K2-K6]

Dependant on which carbs are fitted, the remote float bowl type you can just take the top off the chamber to have a look in there and see what's really in there regarding bits of anything or water etc.

[hondacb750fourk6]

Also check the rubber pipe between carbs i have seen one where slivers of rubber came off the inside when fitting and messed up float needles

Yes it’s a Rover P6 2200 TC 1976 it has a   AccuSpark Electronic Ignition Performance  kit fitted so no points checked carbs took tops off and sprayed carb cleaner in them to clear any blockages and put some three in one oil in the tops checked spark plugs yesterday they were all sooted up one of the plugs the electrode had broken away so will have to replace it as I,ve started to drain all the petrol from the tank as I still think it’s down to the petrol I bought from esso as the car was driving lovely before I filled up with there petrol as I think it’s contaminated with kerosene as someone said on here about another petrol retailer as when I set a light to a little drop of it a lot of black smoke came off it and a very bad smell came off it and yes the Rover is well designed you can unbolt ever panel off it and it’s been well looked after no rot in the usual places only a couple of rust spots one in the boot and two on the rear panel under the rear windscreen what the rear scuttle panel bolts to all the running gear is in good condition thanks

[McCabe-Thiele (Ted)]

Am I right in thinking your Rover has twin Stomberg Type Carbs - does E5 & E10 attack the rubber type carb diaphragms or have you changed them to Vitron to resist the Ethanol?

[K2-K6]

Oooh no Ted, that was the Triumph motorcar that used those 

Said in jest, because the first Range Rover V8 was on Stromberg, apparently for better tolerance of angle, off angle, when typically used on that vehicle.

There was apparently some sensitivity to slide damping on these 4 cylinder Rover engines during development of twin carb setup (hence my question about oil in the dashpot) that caused "flutter" or odd closing of the slide when it should be open.

[McCabe-Thiele (Ted)]

Sounds unusual but our old 1275 S had inch and a half SU's that I changed to inch and a half Stromberg's as they were more responsive and easier to get the mixture right iirc it was an Alexander conversion.

[K2-K6]

Sounds unusual but our old 1275 S had inch and a half SU's that I changed to inch and a half Stromberg's as they were more responsive and easier to get the mixture right iirc it was an Alexander conversion.

My feeling is that, historically, people went the wrong way with SU in how they work. I trim them with oil viscosity in the damper tube to get acceleration mixture advantageous to response, when many focused on getting the main slide as far open as possible, which drives them lean just when they dont need it.
Thicker oil viscosity delays the slide lift, increasing vacuum, making them richer for transient throttle opening....really livens up the torque on them, but without having to go richer on overall jetting.
They also need very, very short wide radius intake profile and never "trumpet" type bellmouth arrangement, think the Rover TC setup does do this as std, as they flow as much air as next bore size up like this, in comparison to long intake equivalent. 

There was very good description in CCC mag years ago researchiing these flow characteristics.

[McCabe-Thiele (Ted)]

My best mate & I who had a similar Mini tried all sorts, 3 in1 oil, brake fluid, Redex UCL etc in the end we used Duckhams 20/50 green  engine oil.

Happy days back then.

PICT0340 by Macabe Thiele, on Flickr

[K2-K6]

EP 90 really makes them "jump" it's like having an accelerator pump system, ran it for different setup on a dyno with V8 Rover, A/F ratio checking to see what it was doing.

You can hear when they go lean (most carb really) but the sound really changes on SU as you can hear it sucking but no pace to pickup, that completely disappeared running high viscosity.