Help! Fuel!

Discussion in 'Mech Tech' started by RM92, Sep 15, 2019.

  1. Just a standard type 1 aircooled with mechanical fuel pump and twin carbs. see pic


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  2. I'm confused, easy done, I know.

    Was it ever fuel injected?
  3. Why confused? It’s just a standard type 1.

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  4. Similar set up to mine, but I have dellorto carbs and you have Weber.

    I've fitted a malapassi fuel pressure regulator to mine. It is fitted after the mechanical fuel pump, and regulates the fuel pressure going to the twin carbs. The pressure can be adjusted to suit the carbs, by someone who knows these things and who has a fuel pressure gauge to set the correct pressure. It is mounted just under the spare wheel well.

    There are other ways of regulating fuel pressure eg electric fuel pump and electric fuel pressure regulator.

    @F_Pantos picture shows a fuel pressure gauge (I think). He can then visually check he has the correct fuel pressure.

    Check if any petrol has got into the oil. If it has don't drive the bus until the issue is fixed and oil will need to be changed.

    Double check that the fuel on the carb isn't just caused by a leak from the fuel feed into the carb. (I once had a leak of fuel from where the fuel hose connects to the fuel banjo which was bolted to the carb). Post a close up of the carb and where the fuel goes in please.

    So this is probably what you need to do:

    Fix cause of the leak (probably needle valves / thicker manifold gaskets stuff mentioned above etc).

    Find out what fuel pressure is best for your carbs (ring eurocarb or someone on here will advise).

    Decide how you want to regulate fuel pressure to carbs, to reduce future issues.

    I would also check your fuel hoses: use ethanol proof fuel hose.

    Drop oil if it has been contaminated with fuel (asap), only refill the oil when you are sure the fuel leak has been fixed.

    Hope that helps.

    This is just based on the little that I know and past carb issues I've experienced. I don't really understand them, other people on here will know far more.
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  5. Should have come to Techenders. I bought a "compound +/- 1.0 bar gauge" off eBay along with a T piece and an adaptor from hose to 1/4 BSP for the gauge.
    I brought it to Techenders.

    The -1 bar vacuum bit was for measuring manifold vacuum to calibrate a MAP sensor I have.
  6. if its still got the factory pump it'll be too high a pressure for the carbs. FI buses had a factory electric pump btw.
  7. Fuel injection engines require about 10 times the amount of pressure versus carbs.
  8. Lots of helpful advice given. I would do the thicker carbs to manifold gaskets, new float needle valves and a new in line large plastic see through fuel filter under the tank to catch stray rust particles which often cause needle valve damage or sticking and block carb jets.

    All simple to do. The other stuff, new pump, pressure gauge, pressure regulator could wait for a bit. Its more complication and extra fuel line joins in the engine bay.

    Your engine bay looks amazing, nice and tidy.
  9. Thankyou, a lot of hard work and restoration has got it to this point now finally enjoying it as I first intended 5 years ago!!! Now little niggles like this pop up keeps me on my toes, I’ve just replaced the fuel filter, new lines for the 20 year guarantee hoses and so I’ll do a full inspection at the weekend and try and find the problem!

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  10. [​IMG][​IMG]

    Few pics of my suspect carb

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  11. Isn't that brown colour dried fuel residue?
  12. My thoughts exactly

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  13. Gasket failed, perhaps?
  14. Maybe, I’ll give it a rebuild and replace all. Better safe than sorry! Rebuild kits have gone up in price to what they used to be!!!

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  15. PIE


    You can reduce the pressure of a standard pump by adding gaskets
  16. Thinking about it, this heat soak talk is getting me thinking I have a problem of that type, as after a good run, and pull up at a services, my bus really does take a good while turning over to start. So maybe a hot start isssue i.e heat soak?

    Cold starting is the turn of a key, so maybe I’ve gone out for my trip Sunday, engines heated up the carbs, heat soak, petrol spills over.. hence my problem. ? Maybe?!? Hence the hissing/gurgle sound, the hot petrol in the carb ?!?

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  17. Heat soak is common problem, mine does the poor starting thing when it's hot, but if that's the case, why is the residue collecting around the gasket?
  18. Where the hot petrol is finding a way out perhaps?

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  19. Maybe, I dunno. I'd always assumed the hot fuel boiled off from out of the float bowl.

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