10 replies to this topic

[vipernewz]

Hey, 

 

I have a 1989 Mini Thirty, it has recently had new Inlet Manifold Gaskets and tappet cover gaskets fitted by my local garage, it was then brought to my attention that the valve in the float chamber would require attention soon as it was starting to stick. 

 

Whilst driving it back from the garage the car started coughing and spluttering along the road... I have now fitted a new float chamber lid which is adjusted to 3.3mm clearance. Once it was fitted it still didn't want to run so pulled a plug to see that it was running really rich and the plugs where covered in black soot. 

 

I have then adjusted the mixture to get it running which I thought meant it was all over... Took the car for a run this morning and it was perfectly fine... just gone to pop to the shops and it will turn over and run for 10 seconds and then cough splutter and slowly die... pulled the plug and its caked in black soot again.... 

 

What would cause it to go from running perfectly fine to really rich without any adjustments being made? will it require a carb rebuild/new jet or could it be another fuel issue like the pump? 

 

Cheers for any help

Tom

 

 

[jaydee]

Two simple checks you must do now, first remove float lid and check the overflow isnt blocked, clean it, also clean the overflow line using compressed air. Then check that the needle valve in the float chamber is properly closing, with the lid upside down, place a 3.5mm drill bit between the float and the lid and gently blow in the inlet pipe, you should feel the valve is closed.

[vipernewz]

Just checked the lid the overflow was clean and have just run some compressed air through the overflow line. I checked the lid and the valve is opening and closing correctly. 

 

Turned it over to see if it made any difference and I this is what the happened; 

 

http://s1086.photobu...f2e54e.mp4.html

Edited by vipernewz, 12 May 2013 - 03:04 PM.

[jaydee]

Looks like a carburation problem.

Firstly check if you have an air leak at the manifold (gaskets have been changed, so probably you have a leak there, could be some nuts are not tight) and that all breathers are connected (engine breather to the carb, vacuum advance and servo pipe to the inlet manifold)

Also if you remove dashpot and piston and see if its flooded of fuel inside or its bone dry and report back

[vipernewz]

I have checked all the nuts and they are tight... But how do I check if there is a leak from the gaskets?
all the pipes are attached in each of their relevant places... And after taking the piston out it is bone dry in there

[jaydee]

Well spray some WD40 over the gaskets in the inlet and listen to engine note, if it changes then you have an air leak, but i wont reccomend you that WD40 test because the vapour can be ignited by the hot exhausts, plus to make that test you need the engine idling at a constant speed and it doesnt seem capable of tickover now.

 

See if the jet is blocked, and the piston moves freely, the big spring isnt damaged and binding, and there is oil in the dashpot.

A quick check on the electrics is also woth a punt, although the rev counter does not move very temperamental, i'd give a check at points,condenser and coil connections.

[vipernewz]

Will give that a check over tomorrow after work and will report back after

[vipernewz]

ok so I ended up taking the carb off to give it a bit of a clean and upon doing so the gasket between the carb and the abutment bracket was completely shot. Ive cleaned up both surfaces and will fit a new gasket tomorrow if I can source one. 

 

There was some muck in the bottom of the float chamber and actually in the carb... have given it all a wipe down with some cloth and re-assembled so fingers crossed this will have sorted things out with the new gasket. 

 

Am I correct in thinking that I need to get the following gasket for between the bracket and the carb ; http://www.minisport...o_AUD2219X.html

 

It also looks like the connectors on the wire to the coil could do with replacing so will get that sorted out too... 

[robminibcy]

If your able to carry out tasks such cleaning the carb ECT. Why did you take it to the garage for new gaskets?! :-P And yes that is the right gasket asuming its still standard carb

[vipernewz]

because i was an idiot and didnt check things properly... it looked like it was leaking from the timing cover which I thought was too big a job for a novice like myself to be told it was leaking down the engine onto that area from above >.<

[vipernewz]

Ok well I've got it all refitted and tweaked... Seems to be working well at the moment

cheers for the help jaydee