Issigonis mini
24 posts
Joined: 28/10/2004 15:54:18
Location: Maidenhead United Kingdom (Excluding channel Islands)
Float chamber overflow!
Firstly I would check to see if the float height is correct if it were set too low it would result in a very lumpy idle and very sooty plugs and well as petrol spewing out of the breather pipe. It may be that dirt is lodging under the float needle and the seat, thus preventing the needle shuting off the flow of fuel. The reason for this could be large rust particles from the tank or even the inside of the rubber hose from the pump is starting the breakdown allowing bits of rubber to jam the needle. If the carb is a HS4 then take off the float chamber cover, leave the petrol pipe conected but remove the float and needle. Then place a jar, jug, container undle the cover and crack the engine untill fuel spills through. If you are really lucky you might see particles/dirt etc come through with the petrol.
Posted: Jul 14, 2005 11:37 AM
John
1948 posts
Joined: 28/05/2006 16:49:46
Location: cambridge United Kingdom (Excluding channel Islands)
what carb?
main thing is location of float chamber, hif u cant see it. when u fit carb to manifold use a plastic spacer, should have one on your manifold. Best fit K&N cone filter with billet stubstack in if possible. rember whatever mods you do you will most likly need to change the carb needle and possibly the damper spring. if not it is most likly the mixture will end up too lean and could damage ur engine as well as loosing alot of power. if you car does have hs4 carb (side mounted float bowl) then it will have a non sprung needle this means u need to centre it when fitted. with performance airfilter and free flowing exaust system a good start would be E3 needle with a blue dashpot spring. then if e3 is too rich M1 needle, if e3 too lean no 7 needle. if you cant be bothered with that just take it to a roling road and let them tune it. also when u connect the manifold its a good idea to plug it into the heater pipes so when u turn on heater it will warm manifold up helping it run and idle in cold weather, alot of people dont but you will have to increase idle more in winter if not, and u wont loose any power when ur heater is off. gd idea to have heater on after starting so u can get choke off sooner, then turn it off once u dont need choke.
Posted: Feb 28, 2007 10:58 AM
Barry Brown
511 posts
Joined: 23/06/2008 12:08:31
Location: New Barn United Kingdom (Excluding channel Islands)
Carb/non starter
it's worrying that you had to straighten the needle a bit. HIF carbs have a 'spring biased' needle so that it either points slightly to one side (air intake or manifold depending on type) these do not bend when adjusting the mixture. The only way to tell is take the needle out of it's guide and roll it across a flat surface to see if you've actually got a bend in it.
the problem of the engine conking out when slowing down is usually a sign of a cracked vacuum breather pipe between carb and rocker cover. people compensate for this over time by richening up the mixture or increasing the revs until it finally lets go. check the end of the breather tube where it joins the carb.
for overhauling the HIF carbs do a google search on BURLEN FUEL SERVICES. they not only have an ecellent set of online guides but you can order genuine SU spares as well. I've just overhauled an HIF6 (1.75") for a Rover working from the web info and changed the butterfly and reset the choke and float without working on this type before. The float should be 1.0mm (+/- 0.5mm) below the float chamber surface when held upside down with the needle valve in situ.
Posted: May 03, 2011 05:37 PM
Cedric Lincoln
2 posts
Joined: 14/07/2012 14:03:06
Location: Union Flacq Mauritius
su carb leaking petrol
Hy, do you have one or two hoses coming on your carb? remove your air filter assy so you can see it clearly, If there is only one, turn your engine on and have a look at the float chamber, it is surely your float that is sinking or your needle that is stuck. Have it cleaned and check your float for damage.
Posted: Sep 04, 2012 06:32 PM
Baza53
14 posts
Joined: 11/03/2013 18:23:59
Location: Spilsby United Kingdom (Excluding channel Islands)
1986 998cc mini mayfair
Definatly fuel starvation,I had the carb off and made all new gaskets to fit, put carb back on and it runs fine.Now I have the occasional leaking from the float bowl,maybe to do with the electric fuel pump do you think I will need a filter king or something else.The carb as had a rebuild, ie,float,needle ect
Posted: Mar 28, 2013 05:32 PM
michael
79 posts
Joined: 02/03/2007 23:58:38
Location: Carpi Italy
fuel tank
i had the problem a rew years back, the carb got blocked, after i give the carb a good clean changed the parts needle float spring etc. i fitted a fuel filter just before the carb in the engine bay. its a plastic one with a paper filter very cheap, but it works, also i put in shell v power petrol that helped to.
Posted: Nov 26, 2010 12:08 PM
Tim
1849 posts
Joined: 18/10/2004 09:40:59
Location: Bournemouth United Kingdom (Excluding channel Islands)
Fuel pouring out of carb vent! HELP
Normally, it just means a bit of dirt is stuck in the needle valve and all you have to do is take the top off the float chamber, blow down the inlet tube a few times, and the job's done. It's a good idea to check the float height while it's off as well.
Posted: Feb 25, 2011 06:44 AM
Do you mean that there is no fuel getting into the float chamber? If that's the case, then you need to take the little needle valve out of the lid of the float chamber and clean it up. Then check it's working by blowing down the fuel inlet pipe and lift the float to make sure it shuts off properly.
Posted: May 03, 2011 08:55 AM
JiMbOb
26 posts
Joined: 14/12/2007 20:54:06
Location: Ammanford, United Kingdom (Excluding channel Islands)
Engine trouble...again
I would say it's the condenser, take the dizzy cap off and switch the ignition on, while ignition is on, get an insulated screwdriver and push the points apart - they will spark and if the spark is a yellowy white your condenser is naffed - 5 minute job to change depending on what dizzy you have - if the spark is a sharp blue colour your condenser is good and it maybe a blockage in the carb, check that the float chamber to needle pipe is clear - take it off and rod or blow it out...HAVE FUN and let me know if either resolves the problem,
Posted: Jun 19, 2008 12:13 AM
Engine troubles
fuel shortage ie little fuel getting to carb eg failing fuel pump meaning it stalls after it has run out. mixture too rich. carb float needle slightly stuck causing flooding, ignition coil failing so when is hot stops.
Posted: Feb 27, 2008 11:55 PM
abs
98 posts
Joined: 08/11/2007 20:20:11
Location: cornwall United Kingdom (Excluding channel Islands)
Re.
Check the vacuum pipe from the dizzy to the carb for splits etc and the breather hose ( you might have knocked one off ). Also have you checked your dash pot oil or the piston in the suction chamber might need cleaning. Another thing to check is the needle valve in the float chamber, it may be sticking or if you have a condenser ( points ignition ) it may need replacing . Hope this helps.
Posted: Feb 04, 2010 08:00 PM
Jake Holmes
172 posts
Joined: 14/02/2009 21:39:11
Location: Walton on Thames United Kingdom (Excluding channel Islands)
re
Indeed, could be a sticking needle valve in the carburetter or wrong float level. Easy enough on a HS4. Failing this there must be a LT circuit problem.
Posted: Feb 13, 2010 10:36 PM
Uncle-Gadget
27 posts
Joined: 12/06/2010 19:08:36
Location: Godalming United Kingdom (Excluding channel Islands)
Strange Fuel Delivery Problem
Thanks for your reply, I have striped the float chamber down, cleaned and checked, all working finn, the float floats fine, and the needle valve closes off, I cant blow through it at all when closed ? Any further thaughts?
Posted: Jul 12, 2010 10:41 AM
tom
15 posts
Joined: 15/11/2006 19:11:40
Location: United Kingdom (Excluding channel Islands)
fuel pump
It runs fine once started. No, it has no fuel filter. And I've checked the float chamber and needle. Both are fine, although I haven't carried ou a full strip down.
Posted: Dec 10, 2006 08:01 PM
HIF44 trouble
firstly a HIF44/6 is too big for a 998 so you will only loose power due to slow intake velocitys, if the 998 is producing over 65bhp it will gain a lil at top end but hif38 would suit alot better if not twin hs2/hs4/hif38(4) on a maniflow intake manifold would be good. (if u free flow insides of hif38/hs4 acording to david vizards a series book then u will have flow aproching hif44 but high port velocitys to increase power.) i would cheak your float in the carb might be damaged and put correct needle valve in it tho.
Posted: Feb 26, 2007 05:51 PM
Fuel Leak? - please help
Check to see if any fuel is coming out of the float chamber breather, the pipe ends down near the starter motor. It might be that the carb is flooding due to dirt under the float needle, dislodged when the carb was removed.
Posted: Feb 21, 2005 10:34 AM
brian
9 posts
Joined: 05/01/2005 20:13:27
Location: thirsk United Kingdom (Excluding channel Islands)
carb problem
i just had the same fault. i took the carb off, removed the bottom plate and found the float needle valve lying in the bottom. i then put it back in pointy side up and the fuel stopped squirting out of the overflow. if the needle valve is reversed this leak will occur. hope that helps
Posted: Mar 19, 2006 07:59 PM
mini90
32 posts
Joined: 30/09/2004 16:35:30
Location: Nottingham United Kingdom (Excluding channel Islands)
..
Presume you have checked replaced all the electrics, checked plug leads are in the correct order, timing set correctly.Have you checked vac advance is working correctly.Change the condensor. Float needle valve isnt sticking, jet not blocked, dashpot piston not sticking.
Posted: Jan 05, 2005 08:13 PM
Hif44 Carb fuel overflowing
It will almost certainly be dirt in the needle valve in the float chamber, preventing the valve from closing properly. You'll need to take the carb off the car and dismantle the bit at the bottom. With luck, all it will need is a good clean out.
Posted: Oct 21, 2020 09:11 AM
Gavin
20 posts
Joined: 16/09/2004 08:47:07
Location: Ashford United Kingdom (Excluding channel Islands)
No more misfire!
I ended up removing the carbs and inspecting the float chamber for any evidence of wear and tear and came accross two completely worn out needle valves. Have replaced them, and she runs like a dream. KC - I will look into getting a set of better suited plugs now you have suggested that, thanks! I belive it has a static CR of about 10.5:1?
Posted: Dec 10, 2004 09:33 AM