7 replies to this topic

[Big Man]

1989 998 Mayfair 78k

 

 

Hi all,

 

After some advice please.

 

Bought the above a couple of months back, did a little body work and now onto engine.

 

It starts first turn but seems to be running on three cylinders or at the very least running exceptionally rough.  

 

Backfires when throttle applied and spits out of carb (kind of like a quick clap of the hands)  has a cone filter fitted.

 

Brand new carb (on when I bought it).   I have replaced HT leads, correctly set points and tappets, fitted new coil and checked that the HT leads are going to the correct plugs using Haynes and a search on here.    Also changed dashpot oil to 20w 50

 

I will be honest and say I have nessed about with the carb in so much as dialing up and down on the mixture screw underaneath the carb, and the idle screw. but other than that nothing.  

 

Plug 1 (nearest the Rad) is very sooted up, others seem okay.  Also have swapped plugs about and it is sooty in number 1. I dont want to be focussed on the number 1 plug in case I miss anything else.  

 

Car starts (albeit rough) on full choke,  will run with a couple of MM of choke but cuts out with no choke. 

 

Not sure what to do moving forward,  sure I have missed something but for the life of me I cant see it!

 

Please any replies keep the simple for stupid (that's me)

 

Cheers in advance.... BM 

[kit352]

Have you checked compression?
Which carb is on it and whats its current state of tune?

[Maccmike8]

Take it to a rolling road.

[Maccmike8]

Its a massive can of worms. A rolling road will be able to tell you whether its carb or other related.

[sonscar]

Personally I would not waste rolling road time getting it running.Old school,remove plug leads one at a time whilst running(carefully)is one cylinder off?Check compression,is one or more cylinders down?Check tappets.Check dissy cap leads and rotor do not assume things are OK.This was second nature when running old cars as a youth.New plugs often work wonders.Minis are simple cars and good grounding for simply fault finding.Good hunting,Steve..

[cal844]

Personally I would not waste rolling road time getting it running.Old school,remove plug leads one at a time whilst running(carefully)is one cylinder off?Check compression,is one or more cylinders down?Check tappets.Check dissy cap leads and rotor do not assume things are OK.This was second nature when running old cars as a youth.New plugs often work wonders.Minis are simple cars and good grounding for simply fault finding.Good hunting,Steve..

I agree

[Big Man]

New plugs going in but the weekend.

Thanks for all the replies.

Not sure what carb is on all is can say it's tilted slightly forward. Float bowl to the side and mixture screw vertically underneath.

Cheers BM

[Big Man]

New plugs going in but the weekend.

Thanks for all the replies.

Not sure what carb is on all is can say it's tilted slightly forward. Float bowl to the side and mixture screw vertically underneath.

Cheers BM