Calling all you carb experts

Hi,
I'm having problems with the hot start on my standard 88 1500 - i'm hoping someone with
more knowledge than me can shed some light on the problem. Here are the symptoms-
Car starts fine from cold and warms up normally to approx 90deg and the drives strong and
smooth with no obvious problems other than a slightly lump idle. When i swithch the engine off hot as long as i start it with a couple of mins it's fine but if i leave it for say 5-10 mins when it restarts it's smokey as if the mixture is really rich sometimes with a misfire which clears quite quickly. Compression is good on all cylinders and the auto choke is working fine with the choke flap fully open when hot, it seems as if when the fuel is hot it's expanding and running into the inlet manifold thus making a really rich mixture on startup. Any help would be appreciated.

Mike

Sounds to me like you may have Carb float height issues and or jetting issues

Do you have a std air box or a K&N setup?

Be worth removing the jets and make a note of its jetting values & compare against std.

Is the car in regular use or has it been standing for some time?

Car is in regular use and has 117 and 135 main jets - idle jets are std as is the
air filter asembly.

Mike, some things to consider:

Are the exhaust manifold heat shield and the paxolin carburettor tray/insulator both present and correct? Is it a mechanical pump? Is the return line from the carb to tank blocked? Is the float chamber inlet needle valve working correctly? It may be that with heat soak, the fuel is expanding in the line between pump and carb, which is defeating a leaky needle valve and flooding the carb. One would expect the engine to run rich all the time, but maybe the pump is a bit marginal too so the flooding is not severe once it's running.

Thanks for your help but it's headgasket after all.

Ah, so it was white smoke then!

Yes - guess I didn't want to face facts! Anyway head is off and at machine shop being cleaned and checked. Looking ahead to
the rebuild what are the correct valve clearances as there seems to be various settings depending on which manual you read.

I use:
Inlet: 0.35-0.45mm
Exhaust: 0.45-0.55mm

Thanks Rachael that's pretty much what I thought.