| [ Total Views: 742 | Total Replies: 10 | Thread Id: 106166 ] |
|
|
 pfillery
Insano Dub Head
Posts: 734
Threads: 160
Registered: December 30th, 2011
Member Is Offline
Theme: UltimaBB Pro Blue ( Default )
|
| posted on May 27th, 2014 at 07:15 AM |
|
|
General causes for idle spped fluctuating, "hunting"?
1600 Kombi engine fitted with twin kadron carbs. Been running "as purchased" until time permits to get some stuff done on her. She's a daily drive
that probably does around 7 to 8km of driving total each day at present.
What generally causes an engine to fluctuate in idle speed? When you rev the engine it will drop back down to idle and then start to climb and fall,
does this a few times (much like a mower engine with an air operated governor does) and after a little while (30 seconds) it will level off and idle
normally, but rev again and it will fluctuate again.
Any ideas what to look for? I'm guessing a carby issue or a jet or something similar. My plan was to do vaslve clearances, change the plugs and leads
and dizzy cap etc then look into getting the carbs right.
I know nothing about twin carbs, how to tune them, balance them etc. It is probably one of the few jobs I would take the car somewhere to have done.
|
|
|
 Bizarre
Super Moderator
The artist formerly known as blue74l
Posts: 12755
Threads: 731
Registered: August 25th, 2002
Member Is Offline
Location: Abbotsford, Sydney
Theme: UltimaBB Pro Blue ( Default )
|
| posted on May 27th, 2014 at 07:35 AM |
|
|
Vacuum leak
My guess is leaky bushings but could be many things
Futue te ipsum!!!
|
|
|
matberry
Super Moderator
Go hard or go home
Posts: 8114
Threads: 134
Registered: March 7th, 2006
Member Is Offline
Location: Cooroy Qld
Theme: UltimaBB Pro Blue
Mood: enjoying waving at all my Kombi buddies from my T3
|
| posted on May 27th, 2014 at 07:56 AM |
|
|
Air leak in manifold x 2 or Kadron linkage issues but not quite right for this by your description
Matt Berry Motorsports...air cooled advice, repairs and mods Ph 0408 704 662
OFF-ROAD,CIRCUIT,DRAG,STREET,ENDURANCE
 |
|
|
pfillery
Insano Dub Head
Posts: 734
Threads: 160
Registered: December 30th, 2011
Member Is Offline
Theme: UltimaBB Pro Blue ( Default )
|
| posted on May 27th, 2014 at 11:26 AM |
|
|
Any easy way to test where the leak would be? It has a vac port on each carb manifold with a brass tee piece to run the brake booster, but uncertain
when the gaskets were changed. Throttle butterfly and linkages seem nice, not loose or sloppy.
Do kads have any sort of auto choke? I don't see any wires so I'm thinking not.
Would I be likely to do any harm to the setting if I pulled each carb and manifold off and replaced the gaskets? I guess this can be done with the
engine in situ as you would usually remove the carbs before dropping the motor. I need to take out my genny at some point which will need to have the
linkage out anyway so maybe can be combined into the one job.
|
|
|
matberry
Super Moderator
Go hard or go home
Posts: 8114
Threads: 134
Registered: March 7th, 2006
Member Is Offline
Location: Cooroy Qld
Theme: UltimaBB Pro Blue
Mood: enjoying waving at all my Kombi buddies from my T3
|
| posted on May 27th, 2014 at 02:02 PM |
|
|
I use a vac pump and gauge to test for leaks in the booster lines. I've seen Kombis with half a dozen leaks in the booster system. A leak in the vac
pipe is just like a manifold gasket leak. It must be fixed.
Matt Berry Motorsports...air cooled advice, repairs and mods Ph 0408 704 662
OFF-ROAD,CIRCUIT,DRAG,STREET,ENDURANCE
|
|
|
beetleboyjeff
A.k.a.: Jeff Walsh
Custom Title Time!
Posts: 1773
Threads: 40
Registered: February 13th, 2009
Member Is Offline
Location: Port Macquarie
Theme: UltimaBB Pro Blue ( Default )
Mood: Drive bugs hard
|
| posted on May 27th, 2014 at 08:05 PM |
|
|
I have the Kadron manual as a pdf. If you want it, send me an email to beetleboyjeff@hotmail.com and I will send it back.
From your ole' mate Jeff
|
|
|
bug68m
Commited Dubber
Posts: 55
Threads: 15
Registered: May 20th, 2012
Member Is Offline
Theme: UltimaBB Pro Blue ( Default )
|
| posted on May 27th, 2014 at 08:15 PM |
|
|
I reckon mats on the money with leaking vaccum hose for the brake booster I fitted twin carbs to my 1600 and could not get the idle or mixture right
found all the hoses under car were porous/leaking replace and problem solved
|
|
|
pfillery
Insano Dub Head
Posts: 734
Threads: 160
Registered: December 30th, 2011
Member Is Offline
Theme: UltimaBB Pro Blue ( Default )
|
| posted on May 28th, 2014 at 07:02 AM |
|
|
I think the vac line underneath is a steel line with plastic pipes attached to it. Does that sound right?
Interesting though that when I hit a certain speed aka certain engine rev range, I can hear a whistling sound under the car which makes me think the
possibility of a vac leak somewhere on the brake system is maybe it.
Is it ok to just renew the hoses with decent vac line or does it need the proper hard plastic hose?
|
|
|
kaiisons
Seriously Crusin Dubber
Posts: 119
Threads: 11
Registered: March 1st, 2009
Member Is Offline
Location: St Clair, NSW
Theme: UltimaBB Pro Blue ( Default )
Mood: Dubbin
|
| posted on May 28th, 2014 at 02:01 PM |
|
|
Mine does this as well. but only with the lights on ?? 1800 type 4 with kadrons.
|
|
|
matberry
Super Moderator
Go hard or go home
Posts: 8114
Threads: 134
Registered: March 7th, 2006
Member Is Offline
Location: Cooroy Qld
Theme: UltimaBB Pro Blue
Mood: enjoying waving at all my Kombi buddies from my T3
|
| posted on May 28th, 2014 at 02:29 PM |
|
|
Lights on increases the load on the engine via the alternator. Increased load is increased manifold vacuum.
Squeek underneath is definately a place to start. Check all the joints. The factory plastic is great but the rubber seals required at each connection
are often cracked or even missing. Good quality vac hose will do the job.
Matt Berry Motorsports...air cooled advice, repairs and mods Ph 0408 704 662
OFF-ROAD,CIRCUIT,DRAG,STREET,ENDURANCE
|
|
|
psimitar
Son of Jim - Creator of Good
Posts: 2506
Threads: 148
Registered: January 1st, 2009
Member Is Offline
Location: North East Melbourne, VIC
Theme: UltimaBB Psyche Blue
|
| posted on May 29th, 2014 at 11:21 PM |
|
|
do you have a balance pipe fitted between the carbs? No balance pipe can cause idle issues.
madness is in the eye of the beholder  |
|
|
