Constant high revs and running hot

Discussion in 'Mech Tech' started by Ermintrude, Apr 20, 2019.

  1. Drove bus home today and the revs are constantly high, a lot higher than usual - he also seemed to be running hotter too.

    Could this be due to an incorrect size fuel line?
    My fuel line from the malpassi filter to the first of the twin carbs was leaking, a lot! This has been replaced.

    i thought this should be a 7.3mm hose (but what do i know?) but the chap who replaced it said that was too big and has used 5.6mm hose.

    Would this cause the issues? the 5.6mm does look quite a tight fit onto the carb!

    I need to get the bus to the mechanic on Monday night for a tuesday check over but am concerned that by driving it again like this could do some permanent damage - there are a lot of hills between me and the mechanics -could it cause permanat damage or is it just annoying?

    could it be something else?
  2. Was 23 degrees today!
    Ermintrude likes this.
  3. What carb linkage have you got it might be sticking
  4. The replaced hose comes from the malpassi. Can just se it.

    And goes into here - the lower of the two shown.
  5. no idea. would a pic help?
  6. [​IMG]

    Please know that I know very little about all this but am so worried I may be damaging something by driving it that I will try things but instructions need to be quite simple :(
  7. [​IMG]

    These pics were taken before the leaky hose was replaced.
    nicktuft likes this.
  8. Csp that's s good bit of kit.
    How is the spring back on the go peddle? Is it sticking at all when you take your foot off
  9. Go around and look for a vacuum hose fallen off or split when the mechanic fumbled around changing fuel pipes.

    Something like a brake servo pipe missing or cracked by knocking it might do it.

    And/or look for anything else somebody focussed on the fuel pipes might not notice knocking off the carburettor.

    And yes, it could be serious if not fixed. Although today was warm, it was only say 10 degrees warmer than recently. So the engine would only be 10 degrees warmer..

    If it was really a lot hotter then be worried.

    Try seeing if you can push the throttle linkage more closed. It might be something stupid like an aftermarket throttle linkage catching on carpet at the front. I made my own and the bolt caught under the carpet and held the engine at 3000 rpm while in Esher High Street going to Volksworld camping..
    Jack Tatty, Merlin Cat and nicktuft like this.
  10. not at all - have tried a few times to blast it but the revs aren't changing - just high constantly. really high/fast
  11. davidoft

    davidoft Sponsor

  12. i've not run it since february (been on ramps derusting the chassis)

    fuel pipe changer isn't an aircooled bod - and tbh, i know nothing about what to look for :(

    It ran high coming off the ramps and still after taking up the cab mat and replacing it.
  13. Does it rev high on tick over in neutral ....rev it again in neutral if it sticks higher again then could be sticking cable give it oil down the tube or wd40and check your linkage at bottom of foot pedal these are just simple checks .
    Jack Tatty likes this.
  14. The bit in the jaffa circle is the throttle linkage with the engine OFF press it in towards the front of the bus try twisting it anti clockwise it should move with some resistance then snap back of it's own free will
    Ermintrude likes this.
  15. Put a bigish return spring in linkage somewhere to pull it back to idle/tick over.
  16. @Ermintrude i can put your mind at ease, the replacement hose won’t cause the van to run fast or run hot, it could be the throttle is sticking , bring it to EG and I’ll fix it for ya:thumbsup:
    Lasty, Jack Tatty and Ermintrude like this.
  17. no, just some help so i don't toast my engine while taking it to the mechanic.
    nicktuft and davidoft like this.
  18. Yes as said seems to be sticking throttle . As nell says have a fiddle with it engine off . And put spring on if needed.

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