Larry
My Mk2 is a 1147 with AN needles and yes it is a bit rough when idle specially
when hot. It looks like it will stop but it doesn't. I suspect there is to much
heat. I want to built a heat shield. 900 rpm is the minimum for me too. Make
sure
there is no air leak around the carb. You changed the throttle shafts but did
you
check if the size of holes (where the shaft goes in on each side of the carb)
are
not to large du to wear. If it is the case, air will come in and affect the
idle.
Hope this will help.
Jean-Marc Dion
Spitfire MK2, 1967
Canada
The engine is running now, but a bit on the rough side. Idle moves up and down
20 to 35 rpm due to some undiscovered reason (maybe this is normal). Idle is
around 900 rpm and can not seem to get any lower.
I have installed new gaskets, throttle shafts, jets and AN needles but am a
bit confused on the needle sizing. The Burlen Carb web site does not list an
1147 engine for the Spitfire. In checking the Haynes SU manual, appendix 1 on
page 97, it does not list an 1147 engine either. If you go to page 100, a
Spitfire Group ll is listed with an 1147 engine however it indicates AUD H4
carbs with DB needles? What's a Spitfire Group ll?
The MK2 Owners Handbook, 5th edition, lists an 1147 engine with HS2 carbs and
AN needles.
I am not even sure that I have an 1147 as there are no identification marks on
the block identification area.
Does anyone have any ideas on needle sizing and why the idle would fluctuate?
One thing that I came across as I examined the 3 sets of carbs that I have is
that of the six carbs, there are 5 different size piston return springs. I
guess that I got lucky as I have two that match, but are they the right
ones???
Larry
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