18 replies to this topic

[Mito]

Rover mini 1991 998
Hs4 carb with AAA needle
Electronic ignition
Stage 1 kit (I think it does anyway. As it's got a heated inlet with no hoses connected and a k&n filter).

It will idle all day if I let it but when out on a run it lacks power and when holding the speed steady for a while on an incline or just above 50mph it will lose power until it's below 50 or slower if it's on an incline. It's a bit like it is starved if fuel.

I've replaced the ht leads, dizzy cap, spark plugs, cleaned the carb and fitted a new waxstat jet and checked the vent on the petrol tank. The spark plugs are white/grey coloured on cylinder 1&4 and more of a browney tea colour on cylinders 2&3.

There's a leak on the inlet/exhaust manifold so I have a new gasket to fit. Is there anything else I should be looking at?

[KernowCooper]

First replace the inlet/exhaust gasket and carry out a basic tune and go from there, have you sprayed wd40 around the inlet to head and see if its sucking in air?

[Mito]

I've not done that but there are exhaust fumes coming from the manifold so I'm assuming the inlet is leaking as well. I'll try wd40 around it before I change it.

[Anthony30]

AAU would be better suited to your spec, IMO.  I tried a AAA needle in mine, and it was too rich.

[Mito]

I've changed the manifold gasket and put plenty of gasket sealant around the inlet so there's no chance it's leaking now.

It's still doesn't like going faster than 50. I can get her up to 70 but have to do so gently and she won't stay there for long before she cuts out and decelerates to 50.

[KernowCooper]

Whats the plug readings like?

[Mito]

Don't know, will take a look at them tomorrow after its been for its mot

[cal844]

We had exactly the same issue (standard 998 with stage 1kit)

Would rev perfect on the driveway,take it out and it would struggle to gain speed, like you say we had to nurse it to get past 50 mph,

Changed carbs, needles, even tried a spare dizzy! and it still wouldn't run!

In the end I said sod it, I will try the coil from our other mini(1275) and it worked!!

Try changing your coil for a known working one to eliminate it

[Mito]

Just back from mot. Among other things it failed on emissions. No surprise there. The emissions report is below and is very high on the co reading.

Attached Files

•  1465922804810-1095754894.jpg   40.2K   15 downloads

Edited by Mito, 14 June 2016 - 04:47 PM.

[Mito]

Here's the spark plugs. Water pump is on the right.
 1465924228226780501869.jpg   102.37K   19 downloads

I can't try a coil as I don't have a spare but will get one if I need too.

[Mito]

I've just put the two middle spark plugs in the hole and left them there for a bit and when I take them out they have droplets of liquid on them. I can't tell if it's fuel or water

[Mito]

Bump

[kyle9832]

Bump

seems to me that it is too rich, you say when you try and build speed it starts to fall again, so i am deffinatley leaning to way too rich, try turning the adjuster on the jet about a turn in and try again see if it improves any, give the engine some stick to get it nice and hot and if it improves when hot that also may be some clue as to its running to rich, although the plugs dont look to bad it is still my main thought...

[Mito]

So not head gasket or timing? I was starting to think head gasket with the two middles being different to the outer ones.

Are the blobs of liquid appearing on spark plugs likely to be fuel? They evaporate within a minute or two.

[kyle9832]

So not head gasket or timing? I was starting to think head gasket with the two middles being different to the outer ones.

Are the blobs of liquid appearing on spark plugs likely to be fuel? They evaporate within a minute or two.

the centre do generally run richer than the outer due to the shared port design, i dont think the problem is your headgasket, im pretty sure its mixture that is at fault, and if they evaporate yes its fuel, which leads me again, to say too rich...