Series 3 Weber 32/34 DTML on 2.25 petrol vapour lock woes

Hiya all. My 1980 petrol came to me with a Weber 32/34 DTML and has always suffered difficult starting when hot.

I’ve done the following to try to sort it:
- carb rebuild inc new float, cleared crap out of jets, ran better for a bit (but still trouble when hot)
- set float height to 7mm
- facet posi-flow mechanical fuel pump fitted, bypassing mech lift pump, with bulkhead mounted swirl pot and fuel return line
- synthetic carb spacer
- run fuel hose around front (under thermostat) it used to go over rocker cover
- wrap fuel hose in insulation

It still conks out when gets really hot (eg summer traffic jam) and then won’t start for half an hour.

I’ve got clear fuel line and can see the fuel going to the carb, so pumps’s working. Although if it’s stopped and left, the line goes dry within a minute or so.

There are a couple more things to try but I don’t hold much hope?
- exhaust heat shield (missing)
- check thermostat operation… never seen it try to boil or anything but it seems damn hot in there

Any other tips?
Much appreciated

What is that new looking black object with numerous pipes? Is it a fuel filter?

If the clear fuel line your talking about is the one going from that black thing to the carb, there's something definitely not right

Try a new coil. & stand it upwards(connectors at the top)

remove air filter elbow & see if you are getting full throttle inside & on the throttle body.

Hicap phill said:

Try a new coil. & stand it upwards(connectors at the top)

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When i replaced mine, many years ago, i was told the connections should be at the bottom, putting the air bubble at the other end

kermit_rr said:

What is that new looking black object with numerous pipes? Is it a fuel filter?

If the clear fuel line your talking about is the one going from that black thing to the carb, there's something definitely not right

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hi, it’s a swirl pot. / vapour separator. It has a return line to the tank. As used on the 2.5na lump which has this carb

Hicap phill said:

remove air filter elbow & see if you are getting full throttle inside & on the throttle body.

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As in visually see if the throttles fully open?

Just fit a zenith carb and have done with it, all that other gubbins could then be removed.

Col

olriley said:

hi, it’s a swirl pot. / vapour separator. It has a return line to the tank. As used on the 2.5na lump which has this carb

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Never heard of all that, but it could be the problem of it's not working.
Bypass is, girl pump direct to carb. Are you on the standard mechanical pump still? It should be fine

kermit_rr said:

Never heard of all that, but it could be the problem of it's not working.
Bypass is, girl pump direct to carb. Are you on the standard mechanical pump still? It should be fine

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I fitted it, as these carbs are supposed to have it and are are susceptible to vapour lock without it, but it doesn’t seem to have helped.

kermit_rr said:

Are you on the standard mechanical pump still?

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electric

Colthebrummie said:

Just fit a zenith carb and have done with it, all that other gubbins could then be removed.

Col

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that’s my gut feel, but I’ve spent £s and time trying to get this setup right. Runs so sweet when cool.

olriley said:

hi, it’s a swirl pot. / vapour separator. It has a return line to the tank. As used on the 2.5na lump which has this carb

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I would get rid of that for starters. I have only ever seen them on diesels, and it is likely it is causing your problem.

olriley said:

electric

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I would get rid of that too.

It didn’t have either of them when I got it, but same hot running problems

olriley said:

It didn’t have either of them when I got it, but same hot running problems

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Common sense would suggest to me that the simpler you make the fuel system, the more likely it is to run right.
Try and avoid ups and downs in the lines as much as possible.
On diesels, those separators are fitted in the return lines to remove air bubbles from the fuel. There shouldn't be any air bubbles in there anyway, so I usually take them off, and bin them, they are just something else to leak.

Weber carbs are known not to be that good on a Land Rover, they are not for Land Rovers, but a generic carb that can be fitted to many things.
The most common problem is carb icing in cold weather, but you obviously have another issue.

If you can't sort it out, it could be that getting a different carb is the answer.

The SU carb is supposed to have an electric pump, not sure why but i didn't bother with mine and never had a problem

kermit_rr said:

The SU carb is supposed to have an electric pump, not sure why but i didn't bother with mine and never had a problem

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Morris Minors had the electric pump on the SU, and they used to pack up regularly.

Turboman said:

Morris Minors had the electric pump on the SU, and they used to pack up regularly.

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I was lucky with mine, never packed up, but did stall occasionally. A whack got it pumping again