Hi Guys,

I have a 1310 which has been in the car for years and i just recently changed the carby from a 1 3/4 Su to a GR special upright Weber. Since its been installed i have not been able to get this engine to run right and it is constantly misfiring and hesitating on throttle and has no power going up hill.

I have taken it to GR a few times to get it tuned but without success and i managed to get it right 1 day after playing with the timing and change of plugs and getting the tune right but after a full day of driving it seemed to knock itself out of tune again.

Has anyone has experience in getting these things to run right and does anyone have any tips?

A car cannot go out of tune. Something is failing. What is the fuel pressure like. Check to see if it is at the required pressure. . Also is the coil okay. Check to see if its hot when it starts missing.

Hope this helps

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What do you mean that you have taken it to GR without success? What did he say?

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The bitterness of poor quality (or Crappy Workmanship) remains LONG AFTER the Sweet Taste of Low Price is forgotten.

Well it has an electric pump and it worked fine with a SU, GR tuned it for me one day and got it going to a driveable point (still would miss and hesitate at lights) but the longer i drove the worse it got to the point i would struggle to get off the set of lights. GR tried changing the jet sizes etc but it hasn't helped.

I tuned it myself one weekend and got it spot on and drove it to the mountains, car drove beautifully the whole way and was great except the occasional miss every now and then but other then that it was good. Driving back however it all went south, the car started to miss and hesitate of lights more and more and losing power (feel like its flooded itself), after an hour of driving it got so bad i couldn't keep it going without stopping every 5 minutes to readjust the mixture. when i got home i took the spark plugs out and sure enough the blacks were completely black. Im starting the think something is wrong with the webers mixture screws unwinding but i just wanted to see if anyone else had similar issues and how they go around it.

Post a picture of the carb. Is it new

I would have thought the mixture would be preset by the jets

Did you try a new coil.

I have had rust from the fuel tank get into the float bowl and jamb the jet.

You would clean out the carb and it would go okay. The over fueling would come back. Cleaned the carb by disassembling it and cleaning with carb clean. Tank out for a clean up. New filter at tank end.

You could put your su back on and see if its a carb issue.



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Mountain air thin, Sea-level thicker...could be a clue...

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"Show me the Mini!"

Sounds like it could be rich enough to foul the plugs? It’s really hard to tell without any readings from an afr gauge. They shouldn’t just go out of tune

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sounds like the ignition is failing to me... but I think I would put the SU back on and make sure everything is correct then have another go at the weber

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did I tell you that I won a trophy?

Some people have had problems with dirt and swarf left in these 'Weber' 44IDF fuel passages after Chinese manufacture.
I would pull all the jets out, soak carby in degreaser then blow passages out with compressed air.
Edited for clarity.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Just to confirm are you talking about a weber downdraft IDA or the more mini common weber DCOE. Sizes and current jetting would be of assistance also. Are you sure the auxillary venturies are in the correct way and are not rattling around ( not being held by the retaining bolt)?

What condition is the engine in? How long and how many kms since it was built?

Have you done a compression test and, if so, what are the results? Are any of the cylinders oiling up?

Like others I'm doubting that it's the carby causing the main problem.

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ex-NSW Police 1970 MK II Cooper S
VMCI #43

Ah just a thought, you didn’t actually top up the tank with diesel did you? I have had this problem before, car will run at high revs ok, but struggle to idle, plugs will be black etc. Gets worse the longer the drive it due to plugs fouling.

Its a Downdraft weber but the screw mixtures are not same as i have seen with IDAs. To be honest i don't remember the sizing etc as GR did it at the time.

Engine never had an issue before i put the weber on, it hasn't been built in a while but when i did the compression check with GR few months back it was all good and when the engine had a 1 3/4 SU on it i had no issues.