Lotus Elan

Strombergs spluttering when hot

PostPost by: 661 » Thu Jun 10, 2021 8:30 am

My S4 SE doesn't like to sit in traffic.
Trying to accelerate after a time sitting in a queue on a hot day causes them to cough and splutter and fail, to the point where the revs will not rise. After a period of switch off/cooling things seem to flow normally again.
Could this be the temperature compensation valve?
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PostPost by: david.g.chapman » Thu Jun 10, 2021 5:54 pm

Possibly vapour lock in the fuel line?

I had something similar a couple of years ago in my +2 with strombergs. A hot day and the engine was hot as well. I stopped at a roundabout and the car refused to start. I got trucked back home and the car started immediately when cooled down. When it happens again you could try pouring cold water over the fuel line in the engine bay, This should make the petrol condense and restore the engine.

In my case the vapour lock was caused by not having a plastic spacer between the fuel pump and the block.

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PostPost by: 661 » Thu Jun 10, 2021 8:54 pm

Thanks Dave. It feels as if the plugs are getting fouled. It runs fairly rich at the best of times.
I don't have anything other than instinct to suggets it's probabaly not the same issue, but who knows?
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PostPost by: mbell » Fri Jun 11, 2021 2:05 am

What spark plugs are you running?
'73 +2 130/5 RHD, now on the road and very slowly rolling though a "restoration"
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PostPost by: SENC » Fri Jun 11, 2021 1:55 pm

Graeme - if your temp compensators are stuck or just adjusted so they don't open (as many have been), then you might get the symptoms you're describing. They were designed to open as things heat up to allow more air and lean out the mixture a bit (the strombergs need a bit more richness when cold to run cleanly).

The following link is a good one for reference on how to test and adjust them.

https://vintagetriumphregister.org/temp ... mpensator/
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PostPost by: 661 » Mon Jun 14, 2021 11:46 am

mbell wrote:What spark plugs are you running?


It's a good call, I remember trying many different types and it's certainly got a feel of the plugs fouling from a rich mixture and then taking a time to clean themselves. Without looking I think it is the '6' s, but in all honesty I've found these the best of the bunch , after much discussion years ago with Pat Thomas.
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PostPost by: 661 » Mon Jun 14, 2021 11:53 am

SENC wrote:Graeme - if your temp compensators are stuck or just adjusted so they don't open (as many have been), then you might get the symptoms you're describing. They were designed to open as things heat up to allow more air and lean out the mixture a bit (the strombergs need a bit more richness when cold to run cleanly).

The following link is a good one for reference on how to test and adjust them.

https://vintagetriumphregister.org/temp ... mpensator/


Excellent, thank you
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