July 19, 2014 at 8:22 am #235253
MG TD VW based replica here – had some problems at Carlisle and it turned out I had loose heads and had to do a slight rebuild.
– I have a 1641 with dual Kadrons that have run perfectly w/ no
adjustments for over 7 years. I put everything back together and hit the
road. It seems to run perfectly in the driveway but under way w/ some
acceleration it bogs down badly. I followed the AJ Sims instructions to
tune but have not been able to get in back to normal.
Some facts –
it has a vacuum advance dizy with electronic points. I have already
replaced the distributor cap and rotor, spark plugs , wires, tried it
with another coil, cleaned out the carb filters, cleaned the jets,
cleaned out the carb bowels, checked the inline fuel filters, added dry
gas to the tank, replaced the needle valves on each and more…
I have also attempted to adjust the Accelerator pump.
all this I have a couple of things I have noticed – the passenger side
carb seems to dump fuel into the throat in squirts from the central tube
as well as the normal brass squirt tube – the other side does not seem
to do this – in addition I noticed the intake manifold below the carb is
much colder then the drivers side ( because of the extra fuel? ).
The fuel dumping did abate a bit when I screwed out the accelerator adjustment nut but did not stop completely.
I think I am back to the carbs being the problem but looking for some expert help in diagnosing my problem.
Thanks in advance for your help.
DaleJuly 19, 2014 at 9:36 am #260738
Dale, seems like you already have correctly diagnosed the problem: passenger carb needs rebuilding. I (when I was 16) sold a car that the buyer revealed that the choke was stuck in the choked position. He “stole” the car from me. I vowed to never again let a carb get the better of me. Unfortunately this is a no-beer job.Rebuild it. Buy a kit. Get a good schematic of which orifices do what, a good clean lint free work area with goods light, your air compressor, a can or two of carb cleaner and an assortment of sizes of good sharp screwdrivers and dental picks (for removing o-rings). First clean the outside til it is spic and span (this is like exercising before entering the game).Then carefully take apart. For this step, I like to use an old egg carton or two, putting nuts, screws, parts, pieces into each little cup as you go. Going from left to right top to bottom just like you read makes reassembly easy, – just invert the order. Once apart, squirt fluid in each orifice and notice that it comes out somewhere. (For the last step, you use the little plastic drink stirrer that comes taped to the side of the cleaner and you may want to wear safety glasses.)Clean everything and only use lint free rags. Using a good magnifying glass, carefully examine all adjusting screws and needles. If you see any scoring on the tapers replace with new. If the jet seats are removable, check them also. If they are not, this is just about the only thing that will not be corrected by this procedure.Reassemble, carefully and in inverse order, using new gaskets. Be careful not to overtighten adjusting screws (needles). Since it once ran well, do not change jet sizes if so tempted.It’ll work. I am/was not a professional carb rebuilder but have only failed to get the desired results when a prior rebuilder damaged something. I’ve done this perhaps 50 or so carbs of all types: Dellorto, SU, Rochester, Carter, brand X, etc.Don’t use ethanol unless you have no choice! I expect that ethanol ate away or caused an o-ring seal to fail in your carb. If so, the other one is sure to go soon.
Royal2014-07-19 09:40:34July 19, 2014 at 10:15 am #260739Paul MossbergKeymaster
Roy, thank you for the great tips!
Hey Dale…sounds like you should send your carbs to Roy! 😀
Former Owner of a 1981 Classic Roadsters Ltd. Duchess (VW)
2005 Intermeccanica Roadster
If you own a TDr and are not in the Registry, please go to https://tdreplica.com/forums/topic/mg-td-replica-registry/ and register (you need to copy and paste the link)July 19, 2014 at 11:58 am #260740
I walked away from my computer for a few minutes and when I returned, a “no mechanical ability” friend asked “what is a sharp screwdriver?”Like most all folks that work on old watches, clocks or carburetor, I have a set of special screwdrivers that have little or no taper to them. These are for the brass screws common to these things. The bottom of the blade is sharp enough to use as a mini scraper and absolutely perpendicular and square to the shank. Phillips screws are more rare but their screwdrivers also need to be sharp.July 19, 2014 at 12:41 pm #260741secretagentcatParticipant
Roy, great advice! Ive never rebuilt my carb, Ive paid to have it done twice. I feel confident enough to try it the next time it needs to be done.
Thanks!July 19, 2014 at 7:39 pm #260742
Thanks for the words – was hoping I would get other input between this site and the speedster site but so far your the only one who came up with any input – it seems you concur with my thoughts after trying all my other ideas.
I do have my local VW guy that helped with my engine who rebuilds carbs ( have not been able to reach him yet ) but I might give the re-building thing a try – thanks for thatJuly 26, 2014 at 7:21 pm #260743
Thought I would give an update.
After ordering two re-build kits this week I decided this morning to just replace the accelerator diaphragm on the passenger side carb thinking I knew what was wrong and give it a shot. It did not change anything so I removed the filter on the other side to compare operation and it finally hit me in the face…
Inside the throat of the drivers side carb was a nice clean hole looking down it the carb – should not have been there. It seems when I removed the carbs during engine change out a little brass fitting that says solex ( name? ) and has a tube with tiny holes had fallen out someplace. Digging through the trash ( not yet tossed out ) I found the missing piece and re-inserted. Bingo! In addition the venturi was loose and had to insert a new set screw ( missing ) to tighten it back up.
On the road and all is good – I will need do some final tuning but back to normal.
Sometimes it is the most simple things I overlook.
One last question – Maybe Roy or anybody else with carb experience ? – the piece that fell out went right back into its seat but see no way to lock it in place – any ideas on that? Just sits there?
Thanks for the help guys.July 26, 2014 at 7:36 pm #260744
Dale, let’s see how good a photographer you are.July 27, 2014 at 9:42 am #260745newkitmanParticipant
Roy,Do you think he means the acceleration jet? Sort of sounds like it.
VW based 53MGTD - "MoneyPenny"
"If one thing matters, everything matters" - from the book The ShackJuly 27, 2014 at 1:52 pm #260746
I tried to find a Kadron engine parts blow up on the net so I could give the part a name but could not locate one.
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