Spitfire Hot starting problem, 78 Spitfire

[Joe_Pinehill]

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?

 

[RJS]

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!

 

[Joe_Pinehill]

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.

 

[Don_R]

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.

 

[TR3driver]

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/

 

[Don_R]

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.

 

[Joe_Pinehill]

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.

 

[Dudly]

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.