Ecozile

Thanks for heads up. I selected the one that is compatible with mk3, I guess I will find out soon  ;D

Thanks Tony, I have considered fpr option but electric pump is noisy, so that's another reason why I thought of going back to mechanical pump. Of course I will have the electric pump in the boot as a spare :)

I am about to place an order for following fuel pump for 1970 Mk3 from Rimmers. Part No.: 208493 Currently car has an electrical pump and I believe it is giving me trouble with its high fuel pressure. Looking at the fuel pump picture above, it appears that both fuel hose fittings are connected with some sort of screw type fitting. I am wondering if anyone know if the fuel pump come with those fittings? otherwise where do I buy such fitting to suit fuel pump? Thanking you in advance..

So I spent some time adjusting carbs with Gunson colour tune. I adjusted jets from what was a very lean fuel mixture to correct blue as per manual that came with Gunson. Car can actually pull it’s weight now. Car revs freely up to about 3k and then hesitate and back fires. Hesitation seems to happen regardless if it is under load or not. While driving, when it is hesitating, I have pulled choke out, then it seems to get slightly better but still back fires. I have ordered a pair of AAQ. I have been asked to check if vacuum advance is working or not. Person who asked me to check that seems to think it is more of a miss fire\timing issue. Any pointers there?

Thanks Andrew for confirming tag number. You are spot on, everything bar fuel pump in this car is stock as far as I know. So I am still struggling to understand why car is not drivable with BO s in them.   Thanks for confirmation on those AAQ, wasn't sure if length of needle was an issue. So that clears that  :) I have decided to ditch the tuner and get the car running on my own. So far have borrowed a gunson colour tune, timing light and a carb balancer. I will start from scratch.

Thanks Tony, I need fix needles, so I have picked following using mintylamb graphs. AN are = AAD DL DZ or GR seems to be the best matched fixed needle for AAQ. Anyone using any of those? Any other recommendations?

I have just been told AAQ is incorrect as they are spring loaded needles rather than fixed.

BigT_DK wrote:My spitmkIII (standard worn oil pissing engine, but with K&Ns and extractor manifold) runs on AAQ needles... Thanks, it appears from all online reading, AAQ seems to be the needle I should get michael_charlton wrote:http://www.mintylamb.co.uk/suneedle/ Have a play around Thank you, I have found that site and the other link where it lets you enter values for a given needle sector, then bring up all matching needle. But my problem is that I don’t know how to put that cart in to real life as I have had no experience in swapping needles. 4058 wrote:When you say dyno tune, do you mean a guy with a diagnostic computer, or a rolling road? It was a roller dyno. I agree, no tuning is real tuning unless it is road tuned or dyno tuned. He also had Bosch ETT connected. Maybe it is the good mechanic part that is missing here. I may have to take it somewhere else to get a second opinion. 2674 wrote: I spent ages trying to track it down in the end it was poor float chamber needles that would let the float chamber over fill at idle then empty out at higher revs, they looked perfect when inspected but obviously weren't. These carbs were rebuilt beginning of the year, they ran somewhat okay. Used to miss on high rpm, eg. above 3.5k or so. But that something worth checking again. 2674 wrote: As you have an electronic fuel pump you could also have an over pressure problem, if the pump is too strong for the float valve you will get the same problem the float chamber will over fill at idle. I think the correct pressure for SU systems is about 3 PSI (I am sure someone will correct me if I am wrong). This very well can be the issue here. I have found that pump runs between 3-4 psi. yes, you are correct, pressure for my car, I believe is 2.5 to 3psi. 2674 wrote: I am guessing you have checked this as well but if your carbs were recently rebuilt it would also be worth checking the needles a re centred correctly. Thanks, I have done that. I have also done usual troubleshooting on manual, like timing and valve clearance etc. Since posting here, I have found that BO needles are infact correct needles for Mk 3 1300. Float chamber tags have AUD257 - can someone with a  MK 3 Spitfire confirm that for me? Many thanks in advance to all of you.

Took Spitfire for a tune up and $400 after car still run bad. No power what so ever.. Tuner said it is not having enough fuel throughout the rev range apart from idle. Here is the current setup. Stock motor, cams and head. Rebuilt SU HS2 with BO needles. Electric fuel pump. MK 3 air filter box. Have checked timing, valve clearance. Relatively new plugs,condenser,dist cap, contact points and coil. If run really rich at idle then car is drivable. Setting correct fuel mixture at idle make car undrivable. Correct fuel mixture was determined by reading exhaust gas with the help of Bosch ETT  8.55. My understanding was that BO needles are correct for this application. Of course that has proven to be wrong on dyno tune. What needles do you recommend or what do you have in yours?

I haven’t seen such a progress in such short period on any other restoration project, you sir indeed have lots of time in hand. Well done!!