11 replies to this topic

[Ol timer]

Hi. I have a 1972 mini mk3 998 stage 1 kit with a HS4 carb and a AAU needle. I seemed to be having a stuttering under load around the 2000 rpm range.

If I plant my foot it stuttering like lack of fuel then comes good. It makes no difference putting on the choke.

I have checked the dash pot oil and replaced it with 20w50 as I was out of SU oil. I also replaced the carb spring to a red spring as the car has a stage one kit. It made no difference.

I have replaced the plugs with new ones even though the old ones looked fine.. air fuel mix looks good on the new sparks. Tuned it with a gunson spark colourplug to get blue . But the issue is still there.

Any other ideas to look for ?
I am lost now to know what else to look for

[Quinlan minor]

My first suspect for stuttering under load would be high tension: HT leads, distributor and plug caps.

Voltage requirement by the spark plugs rises with load and may cause tracking issues.

Will it run through the rev range, cleanly, on light throttle application?

[Ol timer]

Yes it does. If I sit in my driveway and just rev it. It all sounds fine. As soon as I take off that's when the issue starts. .

[Ol timer]

Sorry. If I take off slowly then it seems to be better. . But as above in neutral and just sitting there and rev it sounds OK

[Quinlan minor]

Running it up in neutral will not test the HT system.

Inspect, dry and spray cap and leads with 'Damp Start', or similar.

Consider replacing cap, rotor and leads, if they look damaged.

[Ol timer]

Running it up in neutral will not test the HT system.

Inspect, dry and spray cap and leads with 'Damp Start', or similar.

Consider replacing cap, rotor and leads, if they look damaged.

Thanks for your help, will give it a look tonight , pending weather.

I do have new leads in the shed somewhere and will start with those

The Dist is rather old and crusty.. it did come with the mini and I did replace points to electronic about 2 years ago.. at that time the advance plate (if that is what its called)  inside the Dist was a bit crusty and seized.. I did free that up and it has worked since then, maybe that was a good indication as to the condition of the Dizzie

[Quinlan minor]

The coil is also a possible culprit, make sure the area around the HT ouput is clean, but I suggest checking/changing the service items first.

[Ol timer]

Thanks again. Will do the leads soon as I have the chance. I am considering replacing the dizzi as well due to the original issues I had with it in the beginning. I believe it is a 45D. What electronic one would you recommend?

Edited by Ol timer, 06 December 2021 - 07:11 PM.

[Quinlan minor]

Thanks again. Will do the leads soon as I have the chance. I am considering replacing the dizzi as well due to the original issues I had with it in the beginning. I believe it is a 45D. What electronic one would you recommend?

That's outwith my area of expertise.

Any others with recommendations?

[coopertaz]

id stick with standard dizzy as advance curve will be correct just change points and condensor for electronic unit that fits inside cap. then if fails can put old parts in a get you home. also check bob weights in dizzy body are free and springs not snapped. always used AAV in my 998 with stage one no probs.

[Ol timer]

Thanks for that coopertaz. Always wondered about the Aau needle. Always seemed to run rich. More than likely pick up a new dizzy and change the electronic part out of the old one to the new one

[OJDee]

Seem to be having the same issue after.a stage one kit install. Did you get this resolved in the end Ol Timer?