26 replies to this topic

[JDImini]

Hi All,

 

My son's mini isn't running very well seems to be running rich but also has very little power below about 2500rpm

It is a '89 998 with a single SU HS4 carb and stage 1 kit added before we bought it 

 

It has been off the road for sometime having body work done and has only done about 700 miles since being put on a rolling road

 

It has been suggested that the jet may have been sticking or choke not fully releasing

 

both look to be OK now liberally sprayed with WD40

 

I took the carb piston out and as you can see it looks to have quite a lot of carbon deposit on it. Is that normal or could it be an issue? The piston seems to move freely

 

 needle.jpg   89.23K   0 downloads

 

Also had a look at the timing and it looks to be way off but that might just be me doing it wrong. The red arrow shows approximately where the timing mark was showing on the pulley. Strobe gun was connected to spark plug lead nearest the timing mark and vacuum advance/retard disconnected

 

 timing marks updated.jpg   25.87K   0 downloads

 

Thanks for your help

[blacktulip]

Tell us exactly how you checked the timing?

[cal844]

Clean that carb,
check/replace the points (if fitted)

Is there a fuel filter fitted?(if so is it dirty inside?)

Is the air filter clean?

[JDImini]

Tell us exactly how you checked the timing?

Hi blacktulip

Thank you for the question I hope this is what you mean

ran the engine until warm

connected the strobe gun so live off the starter motor, earthed on engine, inductive pickup on what I hope is cylinder number 1, right hand cylinder when looking into the engine bay from the front of the car

disconnect the vacuum advance retard pull the trigger and see where where the notch on the pulley appears

rev the engine and watch the timing mark, it moved but not significantly 

 

I wasn't planning to make any changes just wanted to see if it looked about right

 

cheers

[JDImini]

Clean that carb,
check/replace the points (if fitted)

Is there a fuel filter fitted?(if so is it dirty inside?)

Is the air filter clean?

Hi Cal844

 

will clean the carb any suggestions what with?

it has got the electronic distributor

not sure about fuel filter so will check

It has got a K&N filter in the original filter housing but it does look grim so have just ordered the cleaning kit

cheers

[cal844]

Clean that carb,
check/replace the points (if fitted)

Is there a fuel filter fitted?(if so is it dirty inside?)

Is the air filter clean?

Hi Cal844
 
will clean the carb any suggestions what with?
it has got the electronic distributor
not sure about fuel filter so will check
It has got a K&N filter in the original filter housing but it does look grim so have just ordered the cleaning kit
cheers

To clean the carb I remove it(you could do it in place) all I remove is the top cover, piston and needle assembly. I then simply use a 1/4 inch paint brush and scotchbrite (dish scourer sponges would also work) and some fresh petrol. Using the brush you simply need to adgitate the petrol around the piston where it is dirty, then pour some into the carb body and do the same, if there are any heavy soiled areas I use the scotchbrite to rub it off. Then simply rebuild and run the car.

Remember to top up the dashpot oil(I use 1/2 a cap of 20/50 engine oil).


The electronic distributor will aid you in setting the timing(no need to set points gaps etc)

Edited by cal844, 04 March 2018 - 11:36 PM.

[minidaves]

that needle looks skinny for a 998

[dyshipfakta]

Try and set your timing to 5 degrees. See how it goes. Could well be the needle though some people get lucky and they are close enough others need custom needles

[CityEPete]

I've said this before but a perfectly set up standard 998 is always better than a botched stage one which most are from what I've seen.

[JDImini]

Thanks all for your help and advice, I'll post an update when I get chance to put some of your suggestions into action

[JDImini]

Try and set your timing to 5 degrees. See how it goes. Could well be the needle though some people get lucky and they are close enough others need custom needles

Thanks is 5 degrees the second tooth from the top, so next to the one with paint on in the photo, if not which tooth is it

Thanks

[JDImini]

that needle looks skinny for a 998

Hi the needle was replaced and "profiled" when the mini was on a rolling road in Nov 16 and only about 500 miles ago 

[dyshipfakta]

disconnect you vacuum bung it up. Then see what timing you actually get the pin after the big one go tdc 4 8 12 16 etc warm it up and set idle to 1000 set timing to 5 degrees see how you go. I would imagine you can advance further then this though.

Edited by dyshipfakta, 07 March 2018 - 10:29 PM.

[CityEPete]

If it has electronic ignition and it was rolling road setup 500 miles ago I can't see the timing needing any adjustment, ever really.

Wouldn't surprise me if nothing more than a tank of super unleaded and an Italian tune up was all it needed, if you've moved the timing and carb setting you might only be able to get it as close as any of us can without a rolling road now.

[Midas Mk1]

As above, how olds the fuel? Also checked basics like fuel filter, lines, ignition components? Changed the plugs?

 

Stuffs not like it used to be back in the day, ignition components fail, fuel filters can get blocked / reduced flow.

 

 

My high spec 1380 wouldnt pull clean past 90 last year after winter recomissioning, combination of poor fuel filter, slightly iffy rotor arm & cap and a couple of spark plugs not fully right. 

 

Good tank of V power & italian tune doesn't harm.