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-   -   [ENGINE] Hot starting difficulty. (https://www.volkszone.com/VZi/showthread.php?t=1591961)

Blue72 27-03-2020 02:32 PM

Hot starting difficulty.
 
Got a slightly odd issue going on with my 1500 s/p Bug:
  1. Cold starting is perfect - immediately cranks into life and runs fine.
  2. Drive until the engine is hot - switch off and then the car will start fine immediately.
  3. Leave it for 5-10 minutes and then the car is really reluctant to start - smells and feels like over-fuelling and it will eventually catch if cranked over long enough.

What I've tried:
  • Check electric choke working correctly
  • Check fuel pump working correctly
  • Check fuel is clean, no debris in bowl
  • Blow through all jets
  • Check float/fuel level
  • Check cut-off solenoid it moving
  • Correct jets in carb
  • Timing etc all correct

Carb is a genuine, refurbed Solex PICT and the car has previously had no issues, but has seen very little use over last 1-2 years.

I've set the fuel level in the bowl actually lower than spec - 15mm - as it just feels like its overfuelling, but it made no difference.

I'm thinking maybe faulty needle valve allowing the carb to over-fill when standing?

Any other ideas?

Bada Ben 27-03-2020 09:29 PM

VW recommended a "technique" for starting a hot engine. Whilst cranking, slowly press the throttle pedal all the way down, and keep it there.
Worth a try before dismantling anything.

Mr.Whippy 27-03-2020 10:19 PM

One of Moby's pics -



https://i.imgur.com/3mYclZb.jpg
Dave.

Big Al 28-03-2020 12:12 PM

It's funny as when I learned to drive, my father taught me to press the pedal once, then half press and hold b4 starting. Guess it's always served me well :) tho now redundant with everything modern except my rav4 which needs it too :lol:

Blue72 28-03-2020 12:55 PM

Cheers Guys, understand the advice but this is a new condition - prior to being parked up for a while the car has always started easily, hot or cold, and I’m not doing anything different....

Hoosier 28-03-2020 01:40 PM

CO adjutment?

Blue72 28-03-2020 05:40 PM

Quote:

Originally Posted by Hoosier (Post 16588255)
CO adjutment?

Hmmmm...could be. Although the weird thing is the car has to be left a few minutes after running before the issue occurs. If the mixture was way out, sure the choke could mask it when cold starting but as soon as the choke came off I'd expect to start seeing the issue?
Or am I missing something...?

I think I'll order a new needle valve and see what difference that makes...cheap enough, and you never know.:rolleyes:

crispies 28-03-2020 09:23 PM

Quote:

Originally Posted by Blue72 (Post 16588021)
Got a slightly odd issue going on with my 1500 s/p Bug:
  1. Cold starting is perfect - immediately cranks into life and runs fine.
  2. Drive until the engine is hot - switch off and then the car will start fine immediately.
  3. Leave it for 5-10 minutes and then the car is really reluctant to start - smells and feels like over-fuelling and it will eventually catch if cranked over long enough.

What I've tried:
  • Check electric choke working correctly
  • Check fuel pump working correctly
  • Check fuel is clean, no debris in bowl
  • Blow through all jets
  • Check float/fuel level
  • Check cut-off solenoid it moving
  • Correct jets in carb
  • Timing etc all correct

Carb is a genuine, refurbed Solex PICT and the car has previously had no issues, but has seen very little use over last 1-2 years.

I've set the fuel level in the bowl actually lower than spec - 15mm - as it just feels like its overfuelling, but it made no difference.

I'm thinking maybe faulty needle valve allowing the carb to over-fill when standing?

Any other ideas?

Have you tried unplugging choke;
had this on our 1200 was told to do; fit a non return valve on fuel line and a cork gasket under carb, never understood how this changed things but it worked.:rolleyes:
Also always slowly push accelerator to floor on both our aircooleds anyway.

ainokea 31-03-2020 01:28 AM

If none of the above suggestions have worked satisfactorily, you have a start circuit wiring resistance problem or a bad ground. A faulty coil is also a small possibility.

old gh bug 31-03-2020 10:37 AM

Coil or condenser breaking down


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