15 replies to this topic

[KSTANDSTEVE]

1990 mini checkmate 998cc stage 1

Had the car set up few months back now and has run faultlessly since.

However a couple of days ago the car started running rough when on choke and the car seemed to get bogged down when I accelerated - take foot off throttle and it picked up.

Anyway today the car wouldnt even start. Well it did start but felt like it was only running 1 or 2 cylinders - couldnt get it to pick up so had to leave it on the drive.

Will have a look tonight but any ideas what to check?

I will take all plugs out and clean them and check dizzy cap and leads but I'm thinking its carb/fuel related. Car was running fine late last night when I parked it up.

Cheers

[jaydee]

Spark plug colour?
Car running fine once warm?

[KSTANDSTEVE]

Will have to wait til I get back in from work - plugs will be first visit as its probably flooded now.

Car runs perfect when warm.

Almost certainly its choke related I think.

[KSTANDSTEVE]

Update

Took plugs out - they were on the black side and wet with petrol. - no surprise there.
Cleaned them off and heated them up on gas stove. Turned engine over then put plugs back.

Checked dizzy cap all looked fine but gave it a clean anyway.

Also checked oil level in dash pot - fine

Tried starting and again burst into life on 2 or 3 cylinders. If I try throttle nothing. If I pull choke out engine dies.

Any ideas?

[jaydee]

Could be something as simple as choke adjustment.
How much the choke lever comes out when you pull it and how mush does it lower the jet before opening the thottle butterfly?

[KSTANDSTEVE]

Hi

Choke pulls out 30mm
Jet moves around 10mm in total

[jaydee]

Too much, can you adjust the choke bolt till you have about 5mm movement at the jet?
Is yours checkmate fitted with single HS4 or with twin Hs2?

[KSTANDSTEVE]

Yep single hs4 carb
Will try the adjustment tomorrow

What exactly does the choke operate - just the jet? And idle speed?
Can I clean jets out as this could be the problem if I have rubbish drawn thru

[KSTANDSTEVE]

Anyone else?

[jaydee]

I've wrote a reply to this..strange it 'disappeared' probably its the forum woes..

The choke mecanism lowers the jet by a lever and opens the butterfly by the bolt pushing to the throttle lever, nothing else. This provides mixture enrichment (lower jet) and fast idle speed (butterfly open).
I dont think cleaning can solve the issue, but why not try.
Have you adjusted fast idle speed as per hynes?

[KSTANDSTEVE]

Ah cheers
Ok no secondary jets or anything to worry about
How do I remove jet to clean?
I will check fast idle but guess I need it running for that?

[JacPowell]

Im having the exact same problem just woke up to it like that the other day. Be interesting to see what yours is might give me somewhere to start!

[KSTANDSTEVE]

Gonna be looking at it again today. Gonna start with electrics. Make sure I have spark at all cylinders. Might change condensor and coil to be sure. Then will look at fuel system making sure I have fuel delivery then lastly checking carb over and cleaning jet

Will let you know how I get on

[jaydee]

Electric problems will cause missfire and are less noticeable with richer mixture, you said it works fine once warm..
You have fuel delivery, otherwise plugs wont be black and wet. But you could have a blocked/worn needle jet in the float chamber.
I'd be tempted to remove the float lit and check both the float clearance and the needle jet. Its all explained in the hynes, feel free to ask if you need further explanation.

[KSTANDSTEVE]

Cheers
Checked out electrics today and 4 strong sparks. Deffo thinking fuel now.
Tomorrow will check carb out and fuel delivery
Did try it again today starts and runs on 2/3 cylinders, acc pedal does nothing and choke just cuts engine out.
Will check my Haynes manual
Thanks