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Engine troubles


Hallum

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Hi all,
It was finally time to get the car out of the garage (mk3 spitfire), and as I did I discovered there is an issue with the engine that has developed. It was running fine when it went in just a few months ago.
The engine starts and idles fine, but throttling causes the engine to run poorly and has little to no power. The sound it makes is hard to describe and I have hence added a video where I hope it can be heard. However when the throttle is release it does return to idling fine.

http://youtu.be/I0pN338VPH0

I have reset the ignition timing to 6 degrees as stated in the Hanes manual, set the points gap, checked all sparks and all seems to be fine. Vacuum advance appears to be working when I have tested it manually. Fuel pump has been replaced.
Any input would be greatly appreciated.
Harry

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I would say it is running on just one carb.  This will be either because the fuel pump output is so minimal fuel only reaches the first carb in line or because one carb has a blocked/stuck needle valve or blocked jet tube.

Other possibility is that you have two plug leads swapped over

Nick

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Hi Nick,
Fantastic, you were exactly right, I checked the second in line carbs fuel chamber which was completely dry. No sign of fuel present for sometime.
As I say the fuel pump was replaced with a new unit only a couple of days ago, so perhaps the fuel lines are gone?
Thanks for your help Nick, greatly appreciated!
Harry

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Found the problem! The issue was the valve for the second carb was sticking in the closed position. It turns out it was due to slight wear on one of the valve piston edges that caused a rough edge prevent its smooth movement. A very light dust will super fine grit sand paper has softened the edge. Now the valve moves freely, opening and closing fully with ease, as well as holding closed under pressure.
I did the same to the other valve while I was at it which was a good good too as it was also worn and I would imagine it would have failed soon.
I will put them back on the car tomorrow, fingers crossed.
Thanks for your help guys,
Harry

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