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Wont stay running. CARB SET UP !!!
Posted: Fri Feb 03, 2023 9:22 pm
by thetobymac
Hi,
I am trying to get a 1970 Morris Minor on the road again, it was sat for about 8 years, I managed to drive it 5 miles home, then spent the winter wedlign a new floor in . But I just cant get it to start now.
Over the winter it has had
Alternator
New Distribuot
New LEads
Spark splugs
I have serviced the SU Carb, SU Carb factory is just round corner from me, they even checked it or me
Put it back in the car and I just cannot get it to start up and keep the engine running
I have followed SU CArb base linning procedure.
Used "Hard start" will fire
Poured eg cup of fuel into carb will fire and run
Can some one point me in direction of CARB tips. I have spark, fuel, air...just somethign is wrong.....I just dont know what.
I need it on the road by 13th FEB to get it to a garage......to check the work !!!! I dont want to have to trailer it there
Any pointers gratefully received
Toby
Re: Wont stay running. CARB SET UP !!!
Posted: Fri Feb 03, 2023 9:38 pm
by svenedin
Just ideas these before I get flamed for speculating. Is the fuel stale? This modern fuel seems to only last a couple of months. Is the fuel pump working properly? Easy to check by removing the fuel hose from carb and directing to a container then turning on ignition. You don’t mention any work on the fuel pump. At bare minimum, remove the filter and clean it and remove the cap and clean the points. If fuel pump OK check float level set correctly. You say you have spark but do you have spark at the right time? Any car left standing for years is likely to have a gummed up fuel pump. Not only does the diaphragm stick but the non-return valves too. Carburettor cleaner is quite good at removing the varnish but really total disassembly and overhaul is advisable. May also be wise to check the hard fuel line from tank to pump isn’t blocked with rust (this happened to me). If pump is working fine and fuel level in float bowl is fine it’s just possible that fuel isn’t getting to the jet. The tube from float bowl to jet is a plastic tube with a metal “spring” around it. When replacing this it is possible to kink the inner tube. It’s only the Venturi effect that draws fuel through this little tube so a kink means no fuel.
Anyway, let us know how you get on. I will now look for the basic carb set up instructions…..
Oh and another thing for goodness sake check the brakes and bleed through fluid whilst topping up with new fluid (change the brake fluid) before driving anywhere!
Stephen
Re: Wont stay running. CARB SET UP !!!
Posted: Fri Feb 03, 2023 10:11 pm
by svenedin
Re: Wont stay running. CARB SET UP !!!
Posted: Sat Feb 04, 2023 9:22 am
by thetobymac
svenedin wrote: ↑Fri Feb 03, 2023 9:38 pm
Just ideas these before I get flamed for speculating. Is the fuel stale? This modern fuel seems to only last a couple of months. Is the fuel pump working properly? Easy to check by removing the fuel hose from carb and directing to a container then turning on ignition. You don’t mention any work on the fuel pump. At bare minimum, remove the filter and clean it and remove the cap and clean the points. If fuel pump OK check float level set correctly. You say you have spark but do you have spark at the right time? Any car left standing for years is likely to have a gummed up fuel pump. Not only does the diaphragm stick but the non-return valves too. Carburettor cleaner is quite good at removing the varnish but really total disassembly and overhaul is advisable. May also be wise to check the hard fuel line from tank to pump isn’t blocked with rust (this happened to me). If pump is working fine and fuel level in float bowl is fine it’s just possible that fuel isn’t getting to the jet. The tube from float bowl to jet is a plastic tube with a metal “spring” around it. When replacing this it is possible to kink the inner tube. It’s only the Venturi effect that draws fuel through this little tube so a kink means no fuel.
Anyway, let us know how you get on. I will now look for the basic carb set up instructions…..
Oh and another thing for goodness sake check the brakes and bleed through fluid whilst topping up with new fluid (change the brake fluid) before driving anywhere!
Stephen
thanks, Its a new SU fuel pump, so pump is good. I think it may well be small tube from float bowl, I am going to take a look later today. I have serviced the front brakes. Going to do rear this weekend as well...they currently slow it down a lot better better, but to get it to stop quick, you put your foot down as if you are trying to get to Australia!
Re: Wont stay running. CARB SET UP !!!
Posted: Sat Feb 04, 2023 9:32 am
by svenedin
If it’s a points type SU fuel pump even brand new they can need the points to be cleaned. An oxide film forms on the points in storage. If the electronic version this is not relevant.
Take the lid off the float bowl and check the fuel level. If it is the little pipe from (jet tube) float bowl to carb jet then if kinked inside it’s wrecked and will need replacing. It can be done with the carb on the car (I’ve done it but is fiddly and easy to get wrong especially the tiny o-ring around the end of the pipe to float chamber).
See this video:
https://youtu.be/ZPzu2zzyGCQ
Also ensure the jet is centred correctly and that the choke linkage is correctly lowering the jet or you haven’t a hope of it starting.