Running rich

[Peter Roberts]

An adjunct to Maurice's excellent point about fuel level is to check that the floats are not perforated. Take them out and shake them. You should hear nothing and the they should be of equal weight. _Peter

----- Original Message ----- From: Maurice Paton To: Steve S ; mg-tabc@yahoogroups.com Sent: Tuesday, June 27, 2006 11:01 PM Subject: RE: [mg-tabc] Running Rich A likely cause of running rich would be the level of fuel in the float bowls. You can easily check this by removing the dash pots and observing the fuel level in the top of the jets. You first need to screw the jets up so they are flush with bridge in the carb body and then turn the fuel pump on to fully fill the float chambers (wait until it stops ticking). The fuel level in the top of the jets should be down about 1/8inch. If the level is higher than the top of the jet, fuel will just be being pumped straight into the engine and you SU will continue ticking! Removing the air cleaners should make no difference to the richness of the mixture, just the amount of air (and therefore fuel) that enters the carb. The fuel is sucked from the jet by the drop in air pressure as it is accelerated through the venturie formed between the carb bridge and the carb piston. More air equals more fuel. Maurice TC9357 NZ -----Original Message----- From: mg-tabc@yahoogroups.com [mailto:mg-tabc@yahoogroups.com] On Behalf Of Steve S Sent: Wednesday, 28 June 2006 2:11 p.m. To: mg-tabc@yahoogroups.com Subject: [mg-tabc] Running Rich Other than having the wrong jets, is there anything to look for if I'm running rich? I have the adjusters leaned out all the way and even tried removing the air filters. I have rich-smelling exhaust and plenty of it, plus black moist plugs. Any suggestions welcome! - Steve S, TC8975, LA, CA - Yahoo! Groups Links [Non-text portions of this message have been removed]

[Rothgene Roth]

Steve, also check the floats themselves to be assured that they don't have fuel inside, remove and shake and replace as necessary, then proceed as suggested. Gene Roth

----- Original Message ----- From: Steve Swebsim@pacbell.net> To: mg-tabc@yahoogroups.commg-tabc@yahoogroups.com> Sent: Tuesday, June 27, 2006 7:10 PM Subject: [mg-tabc] Running Rich Other than having the wrong jets, is there anything to look for if I'm running rich? I have the adjusters leaned out all the way and even tried removing the air filters. I have rich-smelling exhaust and plenty of it, plus black moist plugs. Any suggestions welcome! - Steve S, TC8975, LA, CA - [Non-text portions of this message have been removed]

[Ben Cordsen]

Steve, You mentioned you have the carb adjusters leaned all the way out. If by that you mean unscrewed down, in the direction away from the carb pistons, then you are adjusting to the rich side. On the SU carbs, to lean the carb is to screw the adjusters in, towards the piston. A simple observation, might be on the way to getting your mixture right. Also check the other obvious things, such as the float level. Once set, this should not change over the life of the carb unless it is tinkered with. Make sure your needles are shouldered with the bottom of the piston. Other than these 3 things, not much more can go amiss on a SU carb unless it is leaking which again is a simple fix. I am a great fan of SU's...simple, reliable and easy to figure out. Once set up properly, almost never need attention again. Ben, TC 4260 in Colorado _________________________________________________________________ Don t just search. Find. Check out the new MSN Search! http://search.msn.click-url.com/go/onm00200636ave/direct/01/

[fnitz]

As carburetors go, perhaps the best ever invented. I wonder if the inventors actually knew what they had created. Accelerator pumps were not necessary as the design provides for that inherently and additionally, they feature a constant venturi, yielding correct fuel-air ratio at all throttle settings. Simply amazing! Fred TC1353 -----Original Message----- From: mg-tabc@yahoogroups.com [mailto:mg-tabc@yahoogroups.com] On Behalf Of Ben Cordsen Sent: Thursday, June 29, 2006 6:31 AM To: websim@pacbell.net; mg-tabc@yahoogroups.com Subject: RE: [mg-tabc] Running Rich Steve, You mentioned you have the carb adjusters leaned all the way out. If by that you mean unscrewed down, in the direction away from the carb pistons, then you are adjusting to the rich side. On the SU carbs, to lean the carb is to screw the adjusters in, towards the piston. A simple observation, might be on the way to getting your mixture right. Also check the other obvious things, such as the float level. Once set, this should not change over the life of the carb unless it is tinkered with. Make sure your needles are shouldered with the bottom of the piston. Other than these 3 things, not much more can go amiss on a SU carb unless it is leaking which again is a simple fix. I am a great fan of SU's...simple, reliable and easy to figure out. Once set up properly, almost never need attention again. Ben, TC 4260 in Colorado _________________________________________________________________ Don't just search. Find. Check out the new MSN Search! http://search.msn.click-url.com/go/onm00200636ave/direct/01/ Yahoo! Groups Links

[E.Worpe@surrey.ac.uk]

Hi Fred, By virtue of the oil in the dashpot, the accelerator pump action is also temperature compensated. Greater enrichment occurs when the engine is cold, just when it's needed. Regards, Eric. -----Original Message----- As carburetors go, perhaps the best ever invented. I wonder if the inventors actually knew what they had created. Accelerator pumps were not necessary as the design provides for that inherently and additionally, they feature a constant venturi, yielding correct fuel-air ratio at all throttle settings. Simply amazing! Fred TC1353 Yahoo! Groups Links [Non-text portions of this message have been removed]

[joecurto@aol.com]

Another aspect of rich running is a weak ignition or perhaps a later T type cylinder head with 3/4 reach plugs has been fitted and 1/2 reach plugs are being used , this shrouds the plugs and fouls them out. Joe Curto [Non-text portions of this message have been removed]