6 replies to this topic

[Eds.mini.lulu]

hi there.

 

pretty sure my mixture/fueling is out on my 93' mayfair 1275 std hif 44 carb. 

 

car has been on and off the road for many years. started getting possible fueling problems with car. i bought a service kit for the carb and rebuilt about 2 years ago , and have tried previously to 'tune' and set up the carb but it never seems to be right any other things i should consider, coil is relatively new have also checked distrubutor cap seems ok. spark plugs do indicate possible lean mixture. car generally starts first time, runs slightly rough, and has trouble under load, previous problem also seemed when driven for more than 10 -15mins used to stutter and try to stall which is why i thought mixture was problem. haven't replace ht leads, even bought a compression tester to check the cylinders and all fine there.

 

Any ideas to try and get the carb set up correctly. or anything else i should consider

 

thanks for the help.

 

Ed

[KernowCooper]

How are you trying to set the mixture and what to, CO 3% or lift pin and engine stalls or falters to weak, engine revs up and stays there to rich, engine should rev up slightly and resettle which is a good manual reading.

 

Yu need to do a full engine tune inc timing and tappets before doing any mixture adjustments mind ! what needle is in the HIF44?

[Eds.mini.lulu]

Just trying to return it to a standard mixture. as i thought this was the original problem and played around with it after the carb rebuild. should be the original needle as i have  never changed. don't have a exhaust gas analyzer so just trying to manually set it up using the screws on the side of the carb and untill it sounds right.  when you say "lift pin"  what do you mean by this?  to do a full engine tune am i better off time wise putting itt on a rolling road for this?

 

thanks 

[Carlos W]

How old is the fuel?

 

When you stripped the carb was it all as clean as you'd like the operating theatre to be if you were undergoing major surgery?

[Eds.mini.lulu]

fuel is not that old last time i did some work on it. i drained fuel tank put in fresh oil with some fuel cleaner and also cleaned the carb by putting carb cleaner straight into the intake,  as far as i can remember when i did the carb rebuild which was a couple years ago it didnt seemed particulary dirty and i gave it a good clean when rebuilt. 

 

would you recommend maybe stripping again and checking? 

[Eds.mini.lulu]

meant to say put in fresh fuel. not oil....obviously didnt put oil in the fuel tank

[dklawson]

Just trying to return it to a standard mixture. as i thought this was the original problem and played around with it after the carb rebuild. should be the original needle as i have  never changed. don't have a exhaust gas analyzer so just trying to manually set it up using the screws on the side of the carb and until it sounds right.  when you say "lift pin"  what do you mean by this?  to do a full engine tune am i better off time wise putting itt on a rolling road for this?

 

In some of your other posts it sounds like this is an HS series SU carb, not an HIF.  Some of the HS carbs have a pin on the body underneath the suction chamber and towards the intake side of the carb.  When the engine is running at idle you can gently lift this pin and just barely lift the carb piston.  How the engine RPM responds to that piston lifting indicates whether the mixture at idle is too lean, just right, or too rich.  Not all SU carbs have the pin.

 

If you don't have access to a service manual that discusses the SU carb adjustments (either a good Haynes manual or one of the dedicated SU carb books), visit the Burlen web site and read through their tech sections.  They have pages there that explain how the SU carb works, how to disassemble them, and how to adjust and tune them after a rebuild.  It's a great online resource.