Ausmini
It is currently Fri Jul 18, 2025 1:23 am

All times are UTC + 10 hours




Post new topic Reply to topic  [ 13 posts ] 
Author Message
 Post subject: Idling high on twin SU's
PostPosted: Sun Nov 29, 2009 7:29 pm 
Offline
998cc
998cc
User avatar

Joined: Sat Jul 14, 2007 1:42 pm
Posts: 903
Location: Hunter Valley, NSW
Finally started engine and now for the next problem.

Using twin 1.1/4. Idle screws all the way out and still idles high. Thinking I should turn the jet screw up a turn????????.

Also does anyone have a photo of how the throttle cable attaches to the centre swivel between the carbies. I only seem to have minimum movement on the throttle pedal (about an 1").

Also a ton of smoke coming out of exhaust. Is this usual on starting a new engine??????

Many thanks

_________________
Dave K.
1979 Moke Californian + 1981 'Coke' Moke


Top
 Profile  
 
PostPosted: Sun Nov 29, 2009 7:59 pm 
Offline
religious status
religious status
User avatar

Joined: Fri Mar 19, 2004 6:19 pm
Posts: 39754
Location: near Baulkham Hills, NSW
miniDave wrote:
Finally started engine and now for the next problem.

Using twin 1.1/4. Idle screws all the way out and still idles high. Thinking I should turn the jet screw up a turn????????.

Also does anyone have a photo of how the throttle cable attaches to the centre swivel between the carbies. I only seem to have minimum movement on the throttle pedal (about an 1").

Also a ton of smoke coming out of exhaust. Is this usual on starting a new engine??????

Many thanks

Did you remove the throttle spindles when you blinged the carb bodies up? If so you will need to centralise the butterfly in each one.
This is done by loosening the 2 screws, then hold the throttle closed with the idle screws backed off, and retighten the screws.
Hold up to the light with throttle closed, you should see no light at top or bottom.

_________________
DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R. :mrgreen:


Top
 Profile  
 
 Post subject:
PostPosted: Sun Nov 29, 2009 8:10 pm 
Offline
998cc
998cc
User avatar

Joined: Sat Jul 14, 2007 1:42 pm
Posts: 903
Location: Hunter Valley, NSW
Yes - did that. Also did:

Had GR look at the needles and appeared to be the right type.
Screwed needle to correct position on dampner.
Jets wound down 1.5 turns from flush.
New red carbi springs.
Fill top of dampner with correct SU oil.
Fuel bowls are level - new seals
All new gaskets and all nuts are tight.

Might take them off again and go through the same procedure.

Regarding not having much throttle - please look at these photos as I believe something might be in back to front:
Image
Image
Image

_________________
Dave K.
1979 Moke Californian + 1981 'Coke' Moke


Top
 Profile  
 
 Post subject:
PostPosted: Sun Nov 29, 2009 9:22 pm 
Offline
1275cc
1275cc
User avatar

Joined: Sun Jul 01, 2007 11:25 pm
Posts: 5174
Location: Greensborough, Victoria
Just some thoughts.................
sucking air through the throttle shafts :?: (spray crc, wd40 etc when running and listen for engine idle difference)
were the butterfly's put in the correct way :?:
cable to tight :?:

_________________
http://www.youtube.com/watch?v=nDMkVq1jRGU


Top
 Profile  
 
 Post subject:
PostPosted: Sun Nov 29, 2009 9:27 pm 
Offline
Mods rock!
User avatar

Joined: Fri Oct 03, 2008 9:02 pm
Posts: 5079
Looks like the throttle shaft is in back-to-front


Top
 Profile  
 
 Post subject:
PostPosted: Sun Nov 29, 2009 10:58 pm 
Offline
Bimmer Twinky
User avatar

Joined: Mon Sep 06, 2004 4:36 pm
Posts: 8606
Location: Brisbane
yep,,, Center throttle link is wrong way round

& i`d say you`re sucking air somehwere,,, maybe underneath the manifold, grab a mirror & have a look

_________________
No offence intended here but--> anyone writing a book about minis 30 years ago may not have experienced such worn or stuffed-with components as we are finding these days.

You should put your heart & soul into everything you do.


Top
 Profile  
 
 Post subject:
PostPosted: Fri Dec 04, 2009 6:00 pm 
Offline
998cc
998cc
User avatar

Joined: Sat Jul 14, 2007 1:42 pm
Posts: 903
Location: Hunter Valley, NSW
Well one step forward and one step back.

Pulled the carbies apart and found that one of the pistons was grabbing and not falling back down correctly. Also - must have overfilled the dash pot oil and it had leaked down into carbi and was causing smoke.

Replaced the throttle link with another and now have good pedal range.

NOW to the latest problem . . .
Engine starts OK.
Even with idle screws wound fully out, still idles slightly fast.
Noticeable miss at idle.
Take plugs out and matt black (way to rich)
Cleaned and checked gap, repeat and still matt black.

So I am thinking the jet is wound down too low.
I remember winding the jets up flush to the chamber and then backing off (down) 1.5 turns. Is this correct??????

Is there a starting point where the jet should start at?

Will take the needle out and place it in the jet to make sure it is the correct size.

_________________
Dave K.
1979 Moke Californian + 1981 'Coke' Moke


Top
 Profile  
 
 Post subject:
PostPosted: Fri Dec 04, 2009 6:14 pm 
Offline
religious status
religious status
User avatar

Joined: Fri Mar 19, 2004 6:19 pm
Posts: 39754
Location: near Baulkham Hills, NSW
8 or 12 flats is a good starting point, but don't bet they are still both the same when mixture is even, they are not a Weber...
As said above, your jets may be wrong (.100" instead of .090").

_________________
DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R. :mrgreen:


Top
 Profile  
 
 Post subject:
PostPosted: Fri Dec 04, 2009 6:45 pm 
Offline
998cc
998cc

Joined: Sat Jun 21, 2008 12:43 pm
Posts: 850
Location: Narellan NSW
Dave have you got clearance between the idle screws and the bell cranks on the choke piviot shaft when the choke is all the way in and is the choke coming off all the way when you push it in ? . Just a thought
Cheers Mark


Top
 Profile  
 
 Post subject:
PostPosted: Fri Dec 04, 2009 7:04 pm 
Offline
998cc
998cc
User avatar

Joined: Sat Jul 14, 2007 1:42 pm
Posts: 903
Location: Hunter Valley, NSW
drmini in aust wrote:
8 or 12 flats is a good starting point, but don't bet they are still both the same when mixture is even, they are not a Weber...
As said above, your jets may be wrong (.100" instead of .090").


Thanks for that - How many flats for for a complete turn (6????)

Will check the needles and the jets.

slacko wrote:
Dave have you got clearance between the idle screws and the bell cranks on the choke piviot shaft when the choke is all the way in and is the choke coming off all the way when you push it in ? . Just a thought
Cheers Mark


Will check this. Seems as if choke postion etc is OK. But then again not having the 'pleasure' of tuning SU's before I am still working things out!!!

BTW brakes are still good now - however brakes lights don't come on :evil: Rather than replace fluid switch and re-bleed brakes I bought a $9 electronic brake switch and wired that in :D

_________________
Dave K.
1979 Moke Californian + 1981 'Coke' Moke


Top
 Profile  
 
 Post subject:
PostPosted: Fri Dec 04, 2009 7:13 pm 
Offline
religious status
religious status
User avatar

Joined: Fri Mar 19, 2004 6:19 pm
Posts: 39754
Location: near Baulkham Hills, NSW
Dave, there are 6 flats on a hex nut, so 9 is 1-1/2 turns and 12 is 2 turns. :lol:

_________________
DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R. :mrgreen:


Top
 Profile  
 
 Post subject:
PostPosted: Sun Dec 06, 2009 1:02 pm 
Offline
Yay For Hay!
User avatar

Joined: Wed Sep 08, 2004 9:27 pm
Posts: 15912
Location: Wodonga - Vic/NSW border
were new bushes put in the carbs? if there is a space between the bush and the inner bore of the carb air will get past the butterfly


Top
 Profile  
 
 Post subject:
PostPosted: Mon Dec 14, 2009 12:45 pm 
Offline
998cc
998cc
User avatar

Joined: Sat Jul 14, 2007 1:42 pm
Posts: 903
Location: Hunter Valley, NSW
Well after a house call from the good doctor, we worked towards getting the carbs to run better.

The jets are in fact 0.90 - so that part is OK.
The needles are AH2 (rich) and I have ordered some new 'M'needles from Burlen in the UK.
Choke is not stuck on.

In the meantime I take the plugs out, clean and replace and within a minute of running again there is a miss again and the plugs very black and wet.

I HAVE to get the blue slip done on thursday and I need the car running reasonably. Because I don't have the correct needles I am suggesting:

Wind the jets up 1 complete turn (1/2 turn from flush) which hopefully will make the mixture less rich (but just enough to run low revs) - will this work?

Not a long term fix but just enough to drive to the garage and back. Currently when I drive around the block a few times, stop and try to re-start it takes a long time to re-start as the spark plugs are drowning!

BTW I have just read the SU workshop manual and there is good section on setting up idle screw and jet height according to engine note etc.

Regards -

_________________
Dave K.
1979 Moke Californian + 1981 'Coke' Moke


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 13 posts ] 

All times are UTC + 10 hours


Who is online

Users browsing this forum: No registered users and 12 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Jump to:  

© 2016 Ausmini. All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.