jackjonesparkes Posted July 5, 2020 Share Posted July 5, 2020 Hi guys and gals im new to the spitfire scene so go easy! Recently bought myself a spitfire that has just been rebuilt by the guy i received it from! tried to take it for a test drive one of the days and the car was really groggy and would cut out as i was slowing down or sat at traffic lights etc. I'd have to restart the car to get it moving again. When driving the throttle response wasn't great and would take a while to catch up. Weather has been naff since then so haven't had chance to start it or investigate since then but i have done today. Couldn't get her started originally so spark tested all the ignition leads. I believe my NO.1 lead was faulty so swapped it out with NO.2 and she managed to start. After starting however even with full choke out if i took my foot off the accelerator she would slowly bog down and cut out. Is this going to be attributed to the ignition lead only? or after replacing will i need to investigate other things too? I'm not great with fault diagnosing cars but can happily fix them if i know the issue! Any help would be appreciated! Jack Quote Link to comment Share on other sites More sharing options...
Velocita Rosso Posted July 5, 2020 Share Posted July 5, 2020 You need to check: plugs are set at 25 thou and clean all leads are sparking at the plug(plug out ,lead on hold to earth) is it still points?..If so check,clean, and reset, maybe change condensor Clean dizzy cap contacts Remove dash pots and set the jets (by winding up to base and wind back down two full turns,12 flats) Top up oil in dash pots .......then start up and check running and tweaking Quote Link to comment Share on other sites More sharing options...
Velocita Rosso Posted July 5, 2020 Share Posted July 5, 2020 ...by tweaking ,I mean setting the carbs...balancing each to run together and then idle speed on both carbs etc Quote Link to comment Share on other sites More sharing options...
glang Posted July 5, 2020 Share Posted July 5, 2020 Yes I know it's a faff but starting from scratch, even including checking the tappets, is the only way to know everything is right and then if there's still a problem it must be down to some component failure.... Quote Link to comment Share on other sites More sharing options...
RobPearce Posted July 5, 2020 Share Posted July 5, 2020 What they said. The engine is an unknown and it's clearly not right. You have no way to know where to look first so your only option is to start from scratch and put everything back to factory default. Quote Link to comment Share on other sites More sharing options...
jackjonesparkes Posted July 5, 2020 Author Share Posted July 5, 2020 Appreciate the help guys! Will give the stuff i can check a go tomorrow weather permitting! Quote Link to comment Share on other sites More sharing options...
glang Posted July 5, 2020 Share Posted July 5, 2020 Might seem a bit OTT but even a compression check on an unknown engine isn't a bad idea if you got access to a tester... Quote Link to comment Share on other sites More sharing options...
jackjonesparkes Posted July 6, 2020 Author Share Posted July 6, 2020 Quoted from Velocita Rosso- You need to check: plugs are set at 25 thou and clean all leads are sparking at the plug(plug out ,lead on hold to earth) is it still points?..If so check,clean, and reset, maybe change condensor Clean dizzy cap contacts Remove dash pots and set the jets (by winding up to base and wind back down two full turns,12 flats) Top up oil in dash pots .......then start up and check running and tweaking So went out today, checked the plugs were set right, all good, checked they sparked at earth, all good. Condenser and dizzy cap were all clean and fine. Started her up and had to have choke fully out, after about 10-15 she was idling on choke without fully dying but as soon as choke went in she would immediately cut out, restarts fine just cant have her not running on choke so cant drive it! Then out came an angry neighbor as id been running the engine a long time and the car is rather loud so had to call it for today. Do you think the next step would be to try and adjust the carb? or does it sound like a diff issue? Quote Link to comment Share on other sites More sharing options...
Velocita Rosso Posted July 6, 2020 Share Posted July 6, 2020 The next step would be to get rid of your neighbour.... Do the carbs, take off the piston chambers, screw the jets up to the carb base, then screw back down two full turns eg 12 flats of the brass nut underneath, check to see the linkage is synchronised and both carbs opening at the same time. Top up the pistons with a drop of oil .Then retry Quote Link to comment Share on other sites More sharing options...
RobPearce Posted July 6, 2020 Share Posted July 6, 2020 Quoted from Velocita Rosso- The next step would be to get rid of your neighbour.... Or ask him to have a go at the builders next door to me, who have NO reason to turn their radio that loud. Anyway, in addition to the jet setting, you should probably re-set the idle screw to a sensible default. You may be needing the choke "fast idle" cam to get any throttle opening. Also check the ignition timing. What exhaust do you have on it? You said it was "loud"? Quote Link to comment Share on other sites More sharing options...
PeteStupps Posted July 7, 2020 Share Posted July 7, 2020 Quoted from Velocita Rosso- The next step would be to get rid of your neighbour.... 🤣 Whenever I have to do any prolonged carb tuning, I try and drive to a secluded spot for exactly this reason. But before you do that I would check the valve/rocker clearances, which you need to do with the engine cold. And the points gap (hot or cold, doesn't matter). If these are far out of spec then no amount of carburettor adjustment will get a smooth idle speed. Have you got a set of feeler gauges and a Haynes manual? Pete Quote Link to comment Share on other sites More sharing options...
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