Spitfire bogs down under acceleration.

[Alans835]

22 minutes ago, Badwolf said:

Go on Alan, you can make it. I got to a show with sooty plugs, choke stuck on, kangaroo 🦘 petrol...the works but I was going!!!! Oh yes, I got back too.

...and, by the way, another time, took her out the day before..running beautifully. Morning of the show wouldn't start, backfired, ran ragged dreadful. I was really upset. Stripped down everything, put back together. Mucked about with the carbs..everything that I could think of. Lady BW was really sympathetic. Made coffee, soothing noises etc and then said "But what have you changed since yesterday". Just cleaned the plugs....???!!!! And put the leads back on in the wrong order. Leads reset, coffee drunk and roared off. So simple..eventually.

Thankyou for the words of wisdom, will have a break tonight might get a look tomorrow if I get a chance. Was having a think and it is much worse when hot/warm. Reading a little on his accuspark and it says it can fail when hot causing the car to cut out. Wondering if I should splash out on an old fashioned distributor with points to rule it out. It has been fitted by the previous owner and it’s not the neatest. As when the car does stop it generally has to wait a while before it will start again. Starting to think I may have a few faults here! 🙈😂

[Pete Lewis]

as i said earlier   have you checked the 12v polarity at the coil     reversed wiring will give lots of grief and so easy to check 

Pete

[Badwolf]

Listen to this man. I do (and look where it gets me!!). Seriously, do the easy, simple stuff first. Check the obvious and then check it again. There is something mind blowing simple here that is so obvious..it isn't, because you have looked at it too many times, even down to taking off the air filters and trying without. Years ago my Dad suggested that when one of my old bangers wouldn't pull proerly. Yes, air starvation, old bunged up filters. Look at what makes it go. Do you have fuel, ignition, air, clear exhaust, correct timing (electronic so no dissy cap on back to front). It might run like a bag of hammers, but it should at least run in some way and not just die. You are not trying to tweak this, just make the b*gger run!! Go on, don't let it beat you.

 

[Alans835]

20 minutes ago, Pete Lewis said:

as i said earlier   have you checked the 12v polarity at the coil     reversed wiring will give lots of grief and so easy to check 

Pete

Hi Pete,

Yes I checked it after you had said looks to be correct. Positive from the ignition and neg to the dizzy. It has a ballasted coil fitted. 
 

Alan

[Badwolf]

Alan, reading back through your thread, you problems have similarities with the ones that I had some time back when my choke was sticking on which, obviously gave an over rich mixture as the engine warmed up. My symptoms were, as I can remember....cleaned sooty plugs, engine started and revved on the drive. Pulled away without a problem, then after a short time started to lose power, misfire, would only accelerate by use of choke/accelerator. Cleaning plugs solved the problem which then repeated next time out. Solved by twerking the choke linkage and correct carb adjustment. However, recently the problem started again and was solved after identifying that the small piece of tape which held the choke cable to the top of the rear carb had come away. A tie wrap solved it. When pushing in the choke, without the tape/tie wrap, there was sufficient play in the cable for the exterior of the cable to move but not the inner. Result, choke not coming off, over rich mixture. I offer all these thoughts as the silly, easily overlooked things that a non mechanic such as me have come across over the past few years, that members of this forum have helped me with. Oh yes, my old electronic ignition started mis firing as well, but that could just be switched back to conventional in seconds. Good luck.

[1969Mk3Spitfire]

Only now read through your thread @Alans835 and I feel your pain. I’ve been preoccupied for far too long with a similar issue.

Not really sure what you mean by “bogs down”, can you describe it, please?

My issue looks to have been the same as @Badwolfdescribed above. I had one sooty plug and only now believe that it is possible to have very different combustion in two cylinders supplied by one carb.

I’ve shortened the choke lever by about 5mm and now have a clean burning plug for the first time in longer than I care to remember. Sadly, after a 10 mile run, hot engine, hot ambient, I still have a misfire/stall at high speed, light load and also kangaroo fuel at initial acceleration from standstill. My next steps will be to strip, clean and blow-through the fuel system.

Perseverance is key as the results are worth the effort. Also, I never fail to be impressed and grateful for the help, advice and experience from within the forum.

Good luck!

[PeteH]

I always regarded sooty plugs as the sign of a rich mixture (overfueling), assuming of course, the Engine is otherwise in good condition. Daft thought, but the jet tube is not "bent" is it?.

I ask, because back in the 60`s, Mini`s, had a tendency to fracture the head stabiliser attachement to the bulkhead, and the jet tube could hit said bulkhead and bend, often not noticably but enough to cause "sticktion"?.

Pete

[Pete Lewis]

some electronic units dont work well on a balasted ignition feed  and if they need a 6 -18 v range can in poor battery states end up with less than 6v in the running condition

it may help if the lecy unit has a 12v feed not a feed from the ballasted coil  

some fit a 3 ohm coil and dump/bypass the ballast system completely 

 

just thinking out the box as so much has been covered with little improvements 

[Badwolf]

If this is a problem with the electronic ignition it explains my reason for having the type of unit with a cross over switch and also Doug keeping a set of points and a screwdriver under his seat. 

[Pete Lewis]

Alan if you also have the herald  swap the dizzy over from that to eliminate electronics 

Pete

[Badwolf]

Alan - On the subject of modern electronic ignition problems, have a look here...

https://forum.tssc.org.uk/topic/2623-back-to-the-plot-at-last-nose-to-tail-1972-spitfire-mkiv-restoration-upgrades/page/32/

..starts near the bottom and on to the next page. I must stress that this was a very cheap unit, but I suppose electronics are electronics!!! This won't help you, but it might bring a smile.

I also found Pete's advice when I had running problems here..

https://forum.tssc.org.uk/topic/2623-back-to-the-plot-at-last-nose-to-tail-1972-spitfire-mkiv-restoration-upgrades/page/4/

and this too...

https://forum.tssc.org.uk/topic/2623-back-to-the-plot-at-last-nose-to-tail-1972-spitfire-mkiv-restoration-upgrades/page/10/

..probably won't help, but at least it will show you that other people have problems too..you are not alone!!!

 

[Alans835]

Hi folks, unfortunately The spit didn’t make the show I did go along though there was some lovely cars 1 exceptional herald with revolution wheels. Anyway came home. Blew through the fuel line tank to pump but was spotless. I have rechecked the floats in the carbs ensuring they are 4.8mm from the top as per the triumph manual. Then on testing noticed that spark dropping off showing an intermitant spark at the plugs despite the inline tester showing a spark. As the plugs are brand new I have dugout the non ballasted coil and distributor with points and fitted. Car starts much better although likes more choke. Struggling to get the timing set seems to like it being 14deg btdc at least when I try to get it back to 10-12 the car stalls out. I haven’t done anything with the distributor (points and coil) spark appears to be very strong. Not sure if resetting the points is going to help. Notice the coil to be very hot also. Thought I would give everyone an update so far not out of the woods yet but think it has been a step in the right direction. And a big thankyou for all the help encouragement it is very much appreciated. Thankyou all. 

[Badwolf]

Alan - Where did you get your plugs. I ask because there are a lot of dodgy ones about, either fakes or just poor quality. They don't have an R in the model number..Pete will ask. Maybe clean, regap and try the old ones.

 

 

[Josef]

I wouldn’t worry about the exact timing values. I’ve moved to the adjust for best running, back off a bit, road test method. So if the engine is running well at idle and on he road with 14 deg BTDC, stick with that. 

[dannyb]

51 minutes ago, Alans835 said:

Hi folks, unfortunately The spit didn’t make the show I did go along though there was some lovely cars 1 exceptional herald with revolution wheels. Anyway came home. Blew through the fuel line tank to pump but was spotless. I have rechecked the floats in the carbs ensuring they are 4.8mm from the top as per the triumph manual. Then on testing noticed that spark dropping off showing an intermitant spark at the plugs despite the inline tester showing a spark. As the plugs are brand new I have dugout the non ballasted coil and distributor with points and fitted. Car starts much better although likes more choke. Struggling to get the timing set seems to like it being 14deg btdc at least when I try to get it back to 10-12 the car stalls out. I haven’t done anything with the distributor (points and coil) spark appears to be very strong. Not sure if resetting the points is going to help. Notice the coil to be very hot also. Thought I would give everyone an update so far not out of the woods yet but think it has been a step in the right direction. And a big thankyou for all the help encouragement it is very much appreciated. Thankyou all. 

Mine is set at 18deg btdc. This was set on a rolling road. So stick with 14 if it runs better. 

Danny

[Alans835]

3 hours ago, Badwolf said:

Alan - Where did you get your plugs. I ask because there are a lot of dodgy ones about, either fakes or just poor quality. They don't have an R in the model number..Pete will ask. Maybe clean, regap and try the old ones.

 

 

I got them locally at a motor factors will recheck the gap. Spoke to my dad tonight and he advised I need to have the vacuum hose to the distributor disconnected I had forgotten this step today. Every day is a school day with these old cars. Unfortunately for me this points and condensers is like new technology, by the time I did my apprenticeship as a mechie fitter this type of stuff was past. Enjoying the learning curve though. 

[Badwolf]

My learning curve went through the roof when I joined this forum. The knowledge and help is unbelievable. Without it, I could not have done anything like what I have done, and, it is a pleasure to reciprocate to those where I can help. My stuff is more basic than most here, but I now work on the principal, if I can do it, you can do it. I have put most of what I have learned together on one thread, purely so that I can easily find stuff again, but others appear to have found it interesting as well for some reason!!!

By the way, have you checked the fuel pipes from the fuel pump to the carb float chambers. You mention that you checked from the tank to the fuel pump but nothing after that.