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Spitfire Hot starting problem, 78 Spitfire

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J

Joe_Pinehill

Jedi Hopeful
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From my earlyier post, I know its a hot starting problem. The engine start fine cold. After driving around and it gets hot, it hard , or will not start at all. Is this a carb/choking problem? Any suggestions on places to look in the carb before taking it my Triumph mechanic?
 
I had exactly this same problem on my TR4A. Took me a long time to diagnose. In my case it was an overly rich carb mixture. Car started fine cold (with no choke). But, when hot, the mixture was far too rich.

I tried all the suggested methods of adjusting the carbs to no avail. Wasn't until I purchased a Gunson Colortune tool that I got it perfect. One of the coolest tools I ever bought. It's a glass topped spark plug where you can observe the flame in the combustion chamber and adjust the mixture for that perfect "Bunsen" blue flame you want.

Bob
PS: hope you have a good mechanic. It was my "British" car mechanic who screwed up my mixture to begin with!
 
I cleaned the carb with throttle body cleaner, last night, drove it a half hour this morning, and seems to start fine. I'll keep driving it and see. It sat quite a bit in the past 9 months. I think Ive driven it more this weekend than the past 6 months combined. The cleaning and new activity may have helped, but I've scheduled with my expert triumph mechanic.

Its adds more character to a drive when you're really not quite sure it will start after you stop for a cup of coffee and paper.
 
Joe,

something to check is the float setting. I get fuel percolating out of the carb after a good run. Looks like the float is set a little to high. After a short stop its a little hard starting (rich). if I stop for an hour the gas dissipates and the car starts fine.
 
If lots of Spit owners are having trouble with percolation, it might be worth contacting Joe Alexander and see if he would make a run of carb heat shields to fit. I don't have mine on yet, but I've heard lots of good things about them, including in some cases a significant improvement in fuel consumption.

https://www.the-vintage-racer.com/webroot/Heatshields/
 
Randall,

somewhere I have the CAD designs for Spit heatshields, just been to lazy to get them made.

HS2 and HS4 carbs only. thought I had a stromberg design but can't find it.
 
Two half hour drives in 90degree sun, stoped for 5 minutes, started fine, then 10, then 15 minutes started fine each drive.

I think my biggest problem was just not using it enough.
 
If you have that nasty water choke that could be your culprit.
Same symptoms I had. When I re-built the carb and choke assembly the enrichment needle was stuck in the enrichment tube (green corrosion) as they are brass. I replaced the o-rings and hit it with some light wire brushing and some lube. For me it solved the problem.
 
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