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1600 Aircooled engine (starting when hot)

Posted: 10 May 2012, 19:45
by da.cooper
Hi, i wonder if anyone could help. When my 1980 1600 Aircooled gets hot and i switch off the engine i have trouble starting it until it cools down any ideas. I spoke to some one at Volksworld show and theirs did the same. He said if i turn the ignition on for 30 seconds then start it. It seems to work but not 100%. i would love to cure this if possible, any ideas.???????

Re: 1600 Aircooled engine (starting when hot)

Posted: 10 May 2012, 20:01
by BOXY
Could it be fuel in the hot carb vapourising? Is there a thick gasket between the carb and the manifold to help cutdown on heat transfer?

Re: 1600 Aircooled engine (starting when hot)

Posted: 10 May 2012, 20:13
by PetenAli
Can't see how just having the ignition on for 30 seconds would have any effect - in fact I've always understood that having the ignition on without engine running is bad for the coil. When its hot have you tried starting it with your foot full down on the throttle and keeping it there until it fires? Thats quite a common way to start a hot carbed Aircooled engine and might address what Boxy suggests about vapourisation. Keep us posted with what happens. :ok

Re: 1600 Aircooled engine (starting when hot)

Posted: 11 May 2012, 07:24
by sarran1955
Hello,

1600 Aircooled..... perhaps a CT :wink:

I love 'em :rofl :rofl :rofl

Is everything standard, ie solex carb, and Hall effect ignition. :?:

Does it start well ( 1st time) from cold :?:

Have you ever checked the compressions. :?:

Some engine videos for you...

http://www.youtube.com/user/sarran1955/videos" onclick="window.open(this.href);return false;

I have just set up the CT after a full rebuild on my sons van, goes for the MOT TODAY :!: :!:

Cordialement,

:ok

Re: 1600 Aircooled engine (starting when hot)

Posted: 11 May 2012, 12:24
by kevtherev
compression Ok? (hot)

Re: 1600 Aircooled engine (starting when hot)

Posted: 11 May 2012, 20:15
by bigherb
It could be fuel vaporisation. When the engine is switched off heat rises and vaporises the fuel in the carburettor creating a rich vapour mixture in the carb and air filter. Normal procedure for starting a hot engine is to slowly press the accelerator pedal down (do not pump it) whilst cranking the engine until it starts thus drawing large amounts of fresh air through the carb to purge the rich mixture. Leaving the ignition on for 30 seconds is to power up the auto choke so it it fully open as it starts to close once it loses power but it shouldn't be necessary if every thing is adjusted correctly and the throttle is opened when cranking.

Re: 1600 Aircooled engine (starting when hot)

Posted: 14 May 2012, 21:08
by da.cooper
Hi all thanks for your help. Yes its starts perfectly when cold 1st time. Van has not been used in last 3 years. I have now started using it regurly and things seem to be improving. Its definately running better and i think i got up to 60 mph the other day, lol. Jioking aside i have now fitted a new battery and that definately has improved it so it seems. Im going to run it for a bit and see what happens . If it continues i will get it compression tested.What is the top speed on one of these beasts?

Re: 1600 Aircooled engine (starting when hot)

Posted: 14 May 2012, 21:41
by kevtherev
You already did it...

Re: 1600 Aircooled engine (starting when hot)

Posted: 15 May 2012, 07:56
by Ralf85
The handbook advice for my old T2 advised that the way to start when hot was to hold your foot down on the throttle until the engine fires. Just the opposite to when its cold. Once I did this the starting problem disappeared. Give it a try.
:ok
Patrick