2l Aircooled CU won't fire up

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mrbodly
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2l Aircooled CU won't fire up

Post by mrbodly »

Hi all,

Started my van this morning fired up fine on the button, left it idling for 10 minutes or so. It was idling a tad high so blipped the throttle and the revs cam down to normal then after a minute or so it died.

Tried to restart, it would turn over but wouldn't fire up, it would cough and splutter and backfire. At one point it did fire up but was laboured and with full throttle really struggled and wouldn't pick up speed and after a short while died.

I tried a spare coil and HT leads but no luck. Fuel filter looks clear. Poured fuel down carbs, no joy.

Its got me stumped. It has been in regular use and usually starts on the button. I assume for it to suddenly not fire up it must be electrical.

Any help greatly appretiated.

Regards
Myles

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toolsntat
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Re: 2l Aircooled CU won't fire up

Post by toolsntat »

Not sure how, but has the distributor come loose and moved?
Cheers
Andy
------------------
"GOT ANY OLD TOOLS??"
"WANT ANY OLD TOOLS??"
WANTED old treadle lathe please......
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1980 2.0L Aircooled Blue Hightop Holdsworth Villa Camper
2002 White 2.0l 280 td swb hightop Tranzit works van

cubus
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Re: 2l Aircooled CU won't fire up

Post by cubus »

Vacuum hoses checked and all the connections as well?

Rolf
1980 Westfalia 2.0 CU Assuan Brown Poptop

mrbodly
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Re: 2l Aircooled CU won't fire up

Post by mrbodly »

Hoses all appear to be in place and distributor hasn't moved.

mrbodly
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Re: 2l Aircooled CU won't fire up

Post by mrbodly »

Just a thought, is it possible for the drive teeth to be stripped from the distributor? Could this have happened in normal use?

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tobydog
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Re: 2l Aircooled CU won't fire up

Post by tobydog »

Do you have a spark?
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mrbodly
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Re: 2l Aircooled CU won't fire up

Post by mrbodly »

Thanks for the replies all. Going to check spark and compression in the morning. Will report back.

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sarran1955
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Re: 2l Aircooled CU won't fire up

Post by sarran1955 »

Hello,

Hovering.. :wink:

Cordialement..

:ok
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mrbodly
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Re: 2l Aircooled CU won't fire up

Post by mrbodly »

Morning all,

Checked for a spark, got a strong orange spark on all plugs.

Compression readings:
Cylinder1: 110psi
Cylinder2: 130psi
Cylinder3: 110psi
Cylinder4: 130psi

At one point when doing the compression test on cylinder one the engine stopped turning like it was blocked, switched off the ignition then turned it over again and it was fine. It did that twice. Charged the battery overnight so that is good. Maybe just the starter due to being cranked all yesterday morning then today.

Cheers
Myles
Last edited by mrbodly on 07 Aug 2017, 17:11, edited 1 time in total.

mrbodly
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Re: 2l Aircooled CU won't fire up

Post by mrbodly »

Also, poured a little petrol down the carbs. It sounds like it is trying to fire but doesn't quite manage it. I am wondering about timing but the distributor is rock solid hasn't moved.

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tobydog
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Re: 2l Aircooled CU won't fire up

Post by tobydog »

Should be a blue spark ideally.

I'd check the rotor arm, is it a rev limiting one? Distributor cap?
Knowledge is power
1970 CU

mrbodly
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Re: 2l Aircooled CU won't fire up

Post by mrbodly »

Dizzy cap and rotor arm look ok. Rotor arm is standard.

Does the coil take its earth from the clamp that holds it? The reason I ask is because I tried a spare but it didn't make a difference but I didn't put it in the clamp.

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orangebooboobearcrew
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Re: 2l Aircooled CU won't fire up

Post by orangebooboobearcrew »

Hi,
Have you got fuel being pumped to the carbs?
Old mechanical fuel pumps have perishable diaphragms that can fail.
Take fuel supply pipe off carb and check it is pumping through into a jar (safely - remember very explosive!).
Cheers,
Chris

mrbodly
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Re: 2l Aircooled CU won't fire up

Post by mrbodly »

Thanks Chris. I fitted an electric pump a year or so ago. Tried pouring some fuel into the carbs, wants to fire but not quite managing it.

I'm wondering if the spark is strong enough. As suggested by Tobydog, the spark should be blue. I've got some new plugs, rotor arm and dizzy cap to fit, see if there is any improvement.

mrbodly
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Re: 2l Aircooled CU won't fire up

Post by mrbodly »

Hi all

Just to tie up this thread.

Success, the old girl finally fired up. Fitted new spark plugs, rotor arm, dizzy cap and fitted a spare old coil and voila she fired up!! Must've been a weak spark.

Thanks for all the help.

Cheers
Myles

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