Engine Hot starting difficulty. - VW Forum - VZi, Europe's largest VW, community and sales
 
Machine 7, high quality air-cooled  restoration and performance parts

     
 

Go Back   VW Forum - VZi, Europe's largest VW, community and sales > Tech Forums > Aircooled Mechanical Tech

Aircooled Mechanical Tech A Q & A Forum devoted to Aircooled Mechanical Issues. Got a problem? Then ask in here. Please, no 'For Sale' or 'Want To Buy' ads, plugs for your 'business', links to 'for sale' ads or Ebay links to your (or your mate's) auction (use the VZi 'Classifieds' section) - this also includes thinly veiled 'What's My Car Worth?' threads and "Who Can Sell Me A . . ." posts.

Machine 7, high quality air-cooled  restoration and performance parts
Reply Post New Thread
 
Thread Tools Display Modes
Old 27-03-2020, 02:32 PM   #1
Blue72
Wannabe Chat Slut
 
Blue72's Avatar

Trading feedback: (0)
 
Join Date: Nov 2004
Location: Midlands
Posts: 715
Default 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?
Blue72 is offline   Reply With Quote
Old 27-03-2020, 09:29 PM   #2
Bada Ben
I really must get out more
 
Bada Ben's Avatar

Trading feedback: (0)
 
Join Date: Mar 2007
Location: Black Sticks, Darkest Lancashire
Posts: 6,368
Default

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.
__________________
Nothing is foolproof to a sufficiently talented fool
Bada Ben is offline   Reply With Quote
Old 27-03-2020, 10:19 PM   #3
Mr.Whippy
Help! I'm trapped in here

 
Mr.Whippy's Avatar

Trading feedback: (3)
 
Join Date: May 2002
Location: Thornton, Lancashire, UK.
Posts: 13,335
Default

One of Moby's pics -




Dave.
__________________
Mk 2 Scirocco 1600 GT new clutch kit
Mk 4 Golf front brake discs & pads new in box (288 mm)
- Collect for free - I need the space - PM me.
Mr.Whippy is offline   Reply With Quote
 
Old 28-03-2020, 12:12 PM   #4
Big Al
Help! I'm trapped in here
 
Big Al's Avatar

Trading feedback: (7)
 
Join Date: Dec 2001
Location: Sheffield
Posts: 21,245
Default

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
Big Al is offline   Reply With Quote
Old 28-03-2020, 12:55 PM   #5
Blue72
Wannabe Chat Slut
 
Blue72's Avatar

Trading feedback: (0)
 
Join Date: Nov 2004
Location: Midlands
Posts: 715
Default

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....
Blue72 is offline   Reply With Quote
Old 28-03-2020, 01:40 PM   #6
Hoosier
I'm not an addict... honest!
 
Hoosier's Avatar

VZi Member Sponsor

Trading feedback: (2)
 
Join Date: Sep 2008
Location: The Deep South
Posts: 4,581
Default

CO adjutment?
Hoosier is offline   Reply With Quote
Old 28-03-2020, 05:40 PM   #7
Blue72
Wannabe Chat Slut
 
Blue72's Avatar

Trading feedback: (0)
 
Join Date: Nov 2004
Location: Midlands
Posts: 715
Default

Quote:
Originally Posted by Hoosier View Post
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.
Blue72 is offline   Reply With Quote
Old 28-03-2020, 09:23 PM   #8
crispies
Chat Slapper

Trading feedback: (0)
 
Join Date: Sep 2016
Location: Cambs
Posts: 307
Default

Quote:
Originally Posted by Blue72 View Post
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.
Also always slowly push accelerator to floor on both our aircooleds anyway.
crispies is offline   Reply With Quote
Old 31-03-2020, 01:28 AM   #9
ainokea
Chat Slapper

Trading feedback: (0)
 
Join Date: Nov 2012
Location: Honolulu, Hawaii
Posts: 424
Default

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.
ainokea is offline   Reply With Quote
Old 31-03-2020, 10:37 AM   #10
old gh bug
Seasoned Chat Slut
 
old gh bug's Avatar

Trading feedback: (8)
 
Join Date: Feb 2005
Location: cleveland
Posts: 2,903
Default

Coil or condenser breaking down
old gh bug is offline   Reply With Quote
Reply Post New Thread

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +1. The time now is 03:00 AM.


Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
User Alert System provided by Advanced User Tagging (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.

Disclaimer: For recreational purposes only, some assembly required. Any resemblance to real persons,
living or dead is purely intentional and the site admins are not responsible for direct, indirect,
incidental or consequential ridicule resulting from any defect or failure to perform. No animals
were harmed in the creation of this forum. Colours may fade over time. No other warranty expressed or implied.

volkszone.com

SupportingSupporting Brad's Cancer Foundation

 










 
© Volkszone • Terms and Conditions of use



volkszone.com is an independent Volkswagen enthusiast website owned and operated by VerticalScope Inc. Content on volkszone.com is generated by its users. volkszone.com is not in any way affiliated with Volkswagen AG.