Re Engine running full Revs

Discuss mechanical problems here.
Forum rules
By using this site, you agree to our rules. Please see: Terms of Use
Post Reply
ruislipboy
Minor Friendly
Posts: 17
Joined: Tue Oct 07, 2008 8:26 pm
MMOC Member: No

Re Engine running full Revs

Post by ruislipboy »

Hi yes me again I have just started my engine after it has not run for long while and it runs at full power. The carbs have been rebuilt and has new coil and points. The carbs were rebuilt with new kit. Can any one point me as to what could be wrong and out to sort it out . the choke is working and rest of carb seems ok
Thanks
minor_hickup
Minor Legend
Posts: 1101
Joined: Wed Apr 20, 2005 8:27 pm
Location: East Sussex
MMOC Member: No

Post by minor_hickup »

Is the throttle return spring fitted?
mike.perry
Series MM Registrar
Posts: 10183
Joined: Sun Jul 24, 2005 11:39 pm
Location: Reading
MMOC Member: No

Post by mike.perry »

Is the accelerator cable moving freely?
Are the 2 adjuster screws on the carb unscrewed clear of the cam and throttle stop?
bmcecosse
Minor Maniac
Posts: 46561
Joined: Wed Feb 16, 2005 11:24 pm
Location: ML9
MMOC Member: No

Post by bmcecosse »

If you 'rebuilt' the carbs (more than one ?) - have the throttle plates been assembled correctly to the spindles ?
ImageImage
Image
ruislipboy
Minor Friendly
Posts: 17
Joined: Tue Oct 07, 2008 8:26 pm
MMOC Member: No

Post by ruislipboy »

Have fitted new return spring, new accelerator cable fitted and is moving free. Adjuster screws are clear of cam and stop and the throttle plates have been assembled correctly to the spindles. Just been and check the above.
bmcecosse
Minor Maniac
Posts: 46561
Joined: Wed Feb 16, 2005 11:24 pm
Location: ML9
MMOC Member: No

Post by bmcecosse »

Well - it must be getting air in somehow ! Search and search again - something is obviously not correct. Are the throttle plates right way round - and are they able to close completely ? It's usual when starting an engine like this - to have the twin carbs disconnected, so you set up the idle correctly, and only tighten the joining straps when you have it idling corrrectly.
ImageImage
Image
plastic_orange
Minor Legend
Posts: 1405
Joined: Fri Sep 17, 2004 8:34 pm
Location: Broughty Ferry
MMOC Member: No

Post by plastic_orange »

Did you centre the jets?

Pete
[img]http://img.photobucket.com/albums/v436/sinky_aps/4e634210.jpg[/img] [img]http://img.photobucket.com/albums/v436/sinky_aps/MorrisRain4.jpg[/img]
ruislipboy
Minor Friendly
Posts: 17
Joined: Tue Oct 07, 2008 8:26 pm
MMOC Member: No

Post by ruislipboy »

Have checked and rechecked and checked again I can find no place where air is getting in had carbs off and put them back on, have taken them apart and set them up like books says jet is in middle and still as soon as the engine starts it goes to full power, chock open or close still the same. Throttle open or close still does it
mike.perry
Series MM Registrar
Posts: 10183
Joined: Sun Jul 24, 2005 11:39 pm
Location: Reading
MMOC Member: No

Post by mike.perry »

I seem to remember having a very fast tickover when I first set up my twin carbs. I'm just trying to think how I fixed the problem.
Try the following:-
Undo all the linkage clamps between the carbs
Remove the air filters.
Lift the pistons and check that you can hear them dropping onto the bridge
Make sure you have some slack in the accelerator and choke cables and that the return springs are holding the chokes fully closed, you may have to adjust the levers on the spindle.
When you have checked that tighten the clamps.
You should have three small springs, one for each carb and one for the accelerator cable.
Try that.
If that doesn't work then go to bed, its too late to be working on the car, besides you might upset the neighbours.
Last edited by mike.perry on Wed Oct 29, 2008 9:40 am, edited 1 time in total.
kennatt
Minor Legend
Posts: 2625
Joined: Fri Feb 02, 2007 9:11 pm
MMOC Member: No

Post by kennatt »

take the filters off and make sure the throttle plates are closed start engine and see if they are now open alowing high revs,if they are then the throttle return sytem( springs) are not doing their job. It can't rev at full throttle if the plates are only opening enough to set the idle speed.
bmcecosse
Minor Maniac
Posts: 46561
Joined: Wed Feb 16, 2005 11:24 pm
Location: ML9
MMOC Member: No

Post by bmcecosse »

What exactly did you do when 'rebuilding' the carbs ? Did you have the throttle plates out - and are they back in right way round ? When you look through the carbs - do you see ANY air space around the throttle plates ? If that's not where the air is getting in - then look elsewhere - is the manifold bolting up to the head properly - not being held off slightly by the exhaust manifold ? Is the servo take-off lying open ? Any other holes in the manifold lying open ? To rev up it absolutely MUST be getting air in somewhere - it's nothing to do with jets etc at this stage.
ImageImage
Image
linearaudio

Post by linearaudio »

As BMC suggests, check servo connection/pipe fallen off/split. This will override any throttle setting!
ruislipboy
Minor Friendly
Posts: 17
Joined: Tue Oct 07, 2008 8:26 pm
MMOC Member: No

Post by ruislipboy »

Thank I am checking all the above things and hope that some way along the line to be able to sort it out
Will get back to you and let you know how I get on
mike.perry
Series MM Registrar
Posts: 10183
Joined: Sun Jul 24, 2005 11:39 pm
Location: Reading
MMOC Member: No

Post by mike.perry »

Any progress on the carbs yet?
[sig]3580[/sig]
ruislipboy
Minor Friendly
Posts: 17
Joined: Tue Oct 07, 2008 8:26 pm
MMOC Member: No

Post by ruislipboy »

Hi no not yet have bad cold hope to have a look next week
wibble_puppy
Minor Legend
Posts: 2031
Joined: Tue Sep 07, 2004 6:09 pm
Location: Room 7609
MMOC Member: No

Post by wibble_puppy »

check level of oil in dashpots (if applicable)?

bmcecosse
Minor Maniac
Posts: 46561
Joined: Wed Feb 16, 2005 11:24 pm
Location: ML9
MMOC Member: No

Post by bmcecosse »

Can't see oil in dashpots having anything to do with it whatsoever!
ImageImage
Image
Post Reply