Morris Minor Owners Club

hi. recently just fitted 1 3/4" su to my 1300 marina. before fitting i cleaned all carb out new gaskets etc same nedle though, then before fitting i wound up the mixture bolt so it was level with top then went down 12 flats. once i was happy with it all i then started the mog up and it idle really fast so i just thought i would idle it down witch did help just still quite high untill i ended up taking the idle screw out but was still fast idle so then i leaned the mixture up like 4 flats unit it started to stumble then put the idle screw back in to bring it back up but then i still think it has quite abit of a fast idle oh and i have disconected the throtle and choke to make sure there returning all the way. could this just mean i need to fettle with the mixture or diffrent jets or even me worrying over nothing?
thanks Loz

You say 'same needle' - but same as what? The 1 3/4 carb should have a 100 thou jet - and uses needles with Bxx code. make sure there are no air leaks - that would boost the idle speed. Also check the throttle cable is not too tight - should have a little slack at idle. Same with choke cable of course! I'm guessing it's quite an old 1 3/4 carb - not an HIF 44?

bmcecosse wrote:You say 'same needle' - but same as what? The 1 3/4 carb should have a 100 thou jet - and uses needles with Bxx code. make sure there are no air leaks - that would boost the idle speed. Also check the throttle cable is not too tight - should have a little slack at idle. Same with choke cable of course! I'm guessing it's quite an old 1 3/4 carb - not an HIF 44?

sorry should of made that more clear, its the same one that was in it when i bought it. yeah as i say i disconected the throttle and chock to be 100% sure it wasnt them fowling. I do belive its the old 1 3/4 carb because it has the float chamber on the side. yeah thats the only thing i can think is that i may have an air leak.
Thnaks for your prompt reply Loz

Did you adjust the throttle adjusting screw and the choke tickover screw?