Spitfire Mk 3 glitch - didn't want to accelerate.

[Mark D]

Hi guys, 

On the beg for more advice from you lovely lot please :0) 

Was driving the Spitfire yesterday - did about 50 miles in total. At 35 miles, was doing about 50mph when she didn't want to accelerate much more. Literally nothing there - she kind of 'gurgled' a bit - took her down to about 40 - and back up again - didn't want to do it. 

After a minute or so I was able to open her up again and ran fine for the rest of the journey. 

I did wonder if she's running a bit rich, and perhaps I need to look at the timing and how well tuned the SU carbs are, but wanted to check in here first if this is an occasional glitch, or something to worry about? 

She did a 250 mile round trip a few weeks ago and no issues at all. 

Any advice greatly appreciated as always - thank you :0) 

Cheers,

Mark 

 

[Colin Lindsay]

Sounds like fuel starvation - maybe something momentarily blocked the fuel lines or carb, then cleared again? It wouldn't be rich running as this wouldn't clear so quickly, and would have continued for the rest of the journey until the engine was given a decent break.

Possibly, also a lead working loose momentarily? Check they're all pushed on firmly, however I'd put my money on it being a fuel feed problem.

[Algy]

I have come accross a simular problem in the past, when it is humid and even when the temp outside is fairly high in summer, when driving at moderate speed. The cause was carb icing.

Another possible cause can be vapour lock, if the carb's have not got heat insulators or shields.

One other cause can be condensor or coil breaking down.

These are just some thoughts but not got a lot of experiance with Spit's.

[Pete Lewis]

Very likely its the dreaded rubber slivers shaved of when fuel hoses are refitted float about in the supply after the filter and block the small float needle valve under fuel demand situations 

Check the ht coil is wired with correct polartiy  white to +ve   dizzy to  -ve

Check the rotor brush is in contact with the rotor, and coil ht terminal is not all green and corroded

Check fuel lines for degraded or loose and you end up sucking air  not fuel.

Pete