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Blue smoke and running rough with a new motor

Discussion in 'Bay Tech Clinic' started by seashell, May 10, 2020.

  1. seashell

    seashell Member

    Messages:
    58
    Location:
    Tasmania
    Hi folks
    I have a 2Litre 76 Kombi and the motor has just been redone 3000km ago. It has been running beautifully. I have had it stored for the last month or so and have started it once in that time. Today I went to re-start it and it would not idle, was blowing blue smoke and seemed as though it was running on 2 or 3 cylinders. I checked the plug leads and then I took it for a short drive - maybe 4 km and could not get it over about 40km/h - there was no power really.
    The oil level is about 10mm above the full line which is weird because I have been careful to make sure it was not overfilled - and in fact I haven't had to add any oil since the re-build anyway.
    I am wondering what the hell is going on! Any insights would be appreciated. Thanks
    Dave
     
  2. Barry

    Barry Well-Known Member

    Messages:
    4,644
    Location:
    Abbotsford NSW
    My guess is the needle and seat is sticking in one of your carbs.

    you now have fuel in your oil.

    this will need changed pronto.

    sometimes a short sharp tap to the top of carb clears it.

    otherwise the carb tops need to be taken off
     
    oldman and tintop like this.
  3. Barry

    Barry Well-Known Member

    Messages:
    4,644
    Location:
    Abbotsford NSW
    So this if flooding fuel into the cylinders and stopping it from firing.

    one side of your motor will have wet plugs
     
    tintop likes this.
  4. T1 Terry

    T1 Terry Well-Known Member

    Messages:
    1,421
    Location:
    Mannum South Australia
    Or even worse, the fuel has washed the bore and the new piston has grabbed the bore because the clearances were so close, due to it was not run in yet, and now you have a damaged motor. Not what you wanted to hear but a very real possibility. A compression test will determine if there is any piston/bore damage

    T1 Terry
     
  5. Barry

    Barry Well-Known Member

    Messages:
    4,644
    Location:
    Abbotsford NSW
    Ouch!!!
     
  6. ttmck

    ttmck Super Moderator Staff Member

    Messages:
    2,769
    Location:
    Hallett Cove STH AUS
    Is it parked on level ground what sort of fuel pump set up pls
     
  7. T1 Terry

    T1 Terry Well-Known Member

    Messages:
    1,421
    Location:
    Mannum South Australia
    Sorry for the delay in replying, work has gotten in the way again :lol: The fuel pump I use is one of the Facet type rattle pumps and I use a tachometric relay to control it (like the gadget used on LPG fuel vehicles to turn the gas off if the engine isn't running) These units take a signal from a plug lead or the points and the relay cuts off if it sees less than 50 engine RPM. I guess you could even use a relay powered by an oil pressure light switch so the pump only runs when you have oil pressure.

    T1 Terry
     
    Mordred likes this.
  8. Mordred

    Mordred Super Moderator Staff Member

    Messages:
    2,887
    Location:
    Penna, Hobart
    I have found and seen reported on a lot of forums that facet pumps are a bit or miss pressure wise, especially the Chinese made ones. A better option are pierburg lift pumps and are a rotary vane pump(and more expensive). They are available in 3-5 psi which are suitable for carbs and don’t need a regulator.
    The relay is a brilliant idea, but to make the system as good as the original mechanical pump you also need a fuel cutoff solenoid and it is best to mount it close to the fuel tank. None of the electric pump types have a system to stop flow through when not operating. The mechanical pump has a cut off in it and it stops fuel siphoning into the float bowls, especially when parked on a hill.

    Adrian
     
    Barry likes this.
  9. T1 Terry

    T1 Terry Well-Known Member

    Messages:
    1,421
    Location:
    Mannum South Australia
    If you buy the genuine Facet pump or the Repco branded one, you can select the pump pressure range that suits best and I've found the 5-7psi unit works the best on my 1800. Mine is LPG/petrol so it does have the fuel lock solenoid as well, but I haven't seen one of the Repco or genuine Facet pumps pass fuel unless they are running, the spring holds the piston against the rubber seal, the one way valve in the outlet is spring loaded and the one way valve in the centre of the piston is spring loaded. If the pump does not have the rubber seal in the head of the cylinder they can be very noisy, but an O ring in there quietens then down a lot. As far as the mechanical pump leaking, if it develops a hole in the diaphragm and the drain hole or hose gets blocked up with mud because of where it is mounted, the fuel pumps into the crankcase and dilutes the oil, so yet another way to wreck a good motor.
    My Kombi flooded every time I ran it of petrol using the mechanical pump if it was parked up for more than an hr. When I blanked off the mechanical pump because the diaphragm started leaking and fitted the Facet pump and petrol lock off valve, the problem stopped, but I had fitted the LPG system at the same time so ........
    One great bonus the Facet pump and tachometric relay provides is the ability to prime the carbies with fuel without the need to wind the motor over for ages. If I push it too hard on LPG the converter freezes along with the cross over air cleaner pipe and the carbies them selves, so being able to pump fuel into the carbies gets me going again and provides enough heat to melt the ice.

    T1 Terry
     
  10. Mordred

    Mordred Super Moderator Staff Member

    Messages:
    2,887
    Location:
    Penna, Hobart
    Looks like you have the better than average facet pump. Most common ones around are Chinese copies of those and poor quality. As with most things you get what you pay for. Agree that the electric does help with a quick start and less cranking, but also you get some oil pressure before start if cranking (as long as it isn’t more than a few seconds) before firing especially on a cold start. Above 5 psi is high for solex carbs, and more than the original pump, but if it works for you that’s great.

    cheers

    Adrian
     

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