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carb idle issue

Posted: 10 Oct 2024, 16:48
by what2do
Up until recently the dg ran sweet as a nut.  It was stood for a few weeks, upon using it again (ordinarily it's used every day) it started fine but when idling the revs drop so low that it stalls.   A real pain in the a*** when doing short journeys around town, negotiating junctions and traffic lights, I've had to resort to blipping the throttle when stationary to prevent it stalling constantly.

What re your thoughts people?

Re: carb idle issue

Posted: 10 Oct 2024, 17:13
by TwinTurbo
I have a stalling issue too but it's very random.

Initialy it was quite poor, but freeing up the autochoke made a big difference

Next on my hit list is vacuum pipes and the servo pipe, Just need to find time to do it..

They would be my fist tings to check.

Re: carb idle issue

Posted: 10 Oct 2024, 17:29
by Mocki
Check the cone filter in the carb petrol inlet port , and obviously the main filter down under the cill by the tank
If those are clean and clear , maybe try try the old mechs trick of taking the air filter pipe off the carp cap , start it up and rev it whilst blocking the air intake with your hand , it will suck like mad before it dies , unblock before it stalls , that should move any minor blockages .

Re: carb idle issue

Posted: 10 Oct 2024, 18:12
by TwinTurbo
Actually my first thing was the main fuel filter...  :ok

Re: carb idle issue

Posted: 10 Oct 2024, 20:21
by tobydog
Crap/water in carb, air filter, air leak. Idle jet blocked? Clean carb out....

Check distributor, damp?

Least fuel used ticking over, if any fuel filters were blocked, would it be drivable under load?

Re: carb idle issue

Posted: 10 Oct 2024, 20:33
by TwinTurbo
does it do it every time your on idle, hot,warm , cold.

The idle cutoff valve was also on my list, but sort of ruled that out. ( although have a cunning plan for any future failure )

Re: carb idle issue

Posted: 16 Oct 2024, 17:06
by what2do
Oops, I hit 'Report' instead of 'Reply', sorry admin!

Re: carb idle issue

Posted: 16 Oct 2024, 17:08
by what2do
TwinTurbo wrote: 10 Oct 2024, 20:33 does it do it every time your on idle, hot,warm , cold.

The idle cutoff valve was also on my list, but sort of ruled that out. ( although have a cunning plan for any future failure )

It does it once the engine has warmed up, every single time without fail.  The idle bypass 'clunks' when powered up but is that a definitive test that it's working?  I'm assuming it works like a solenoid - on/off?

Re: carb idle issue

Posted: 16 Oct 2024, 17:11
by crazyhorse
Any joy on this?

Ha just asked this 30 seconds after your post

Re: carb idle issue

Posted: 16 Oct 2024, 17:13
by what2do
crazyhorse wrote: 16 Oct 2024, 17:11 Any joy on this?

Ha just asked this 30 seconds after your post
Not yet, will change the main filter this weekend and report back.  I had blasted the carb jets with a tin of compressed air quite a few times but to no avail.
 

Re: carb idle issue

Posted: 16 Oct 2024, 17:31
by crazyhorse
Ah ok…

Reason I ask Is I was going to put a post with similar symptoms… I was reading about the two filters and saw this in the wiki.. not sure if you have seen it also…

https://club8090.co.uk/wiki/Fuel_system_-_Pierburg

All the way the bottom of the page which is what mocki was talking about.. might be worth a look also

Re: carb idle issue

Posted: 16 Oct 2024, 18:24
by Mocki
what2do wrote: 16 Oct 2024, 17:06 Oops, I hit 'Report' instead of 'Reply', sorry admin!
No problem , sorted

Re: carb idle issue

Posted: 16 Oct 2024, 18:28
by Mocki
what2do wrote: 16 Oct 2024, 17:08
TwinTurbo wrote: 10 Oct 2024, 20:33 does it do it every time your on idle, hot,warm , cold.

The idle cutoff valve was also on my list, but sort of ruled that out. ( although have a cunning plan for any future failure )

It does it once the engine has warmed up, every single time without fail.  The idle bypass 'clunks' when powered up but is that a definitive test that it's working?  I'm assuming it works like a solenoid - on/off?

Simplest way i can think of ruling the idle cut off solenoid out is either exchange it for a known good one , or disconnect the power to it whist the engine is running at idle ( if you can get it to idle that is ) you will see. If there is any difference

Re: carb idle issue

Posted: 16 Oct 2024, 21:07
by TwinTurbo
Having one of these is an easy way to rule out the rare and expensive Solenoid.

ImageImage

Re: carb idle issue

Posted: 16 Oct 2024, 21:17
by Mocki
What are we looking at ?