14 replies to this topic

[luismx123]

hey all,

Thought Id start my baby up today again as its been a while. Its fairly cold here....-2* today... and I started my mini up, pull some choke and got it reving to 1500-2000 for a bit. Then i removed the choke and the car started stuttering so I kept him running with some light throttle work. I got it running for around 3-4min now and wanted to give it a little rev to 3000 and it started bogging down. I kept trying to "pump" the throttle to get the revs up but it was hit and miss. Id say around 50% of the time it bogged down and dropped rpms, then slowly regained.  

Any reason for this?

Cheers

[cal844]

How old is the fuel? When was it last serviced?

[pusb]

You sure you didn't just push the choke in too soon?

[Pigeonto]

Have you tried turning it off and then back on again ? lol

Being serious actually, I'm wondering if the carb iced. If you turned it off for 5 minutes and let the exhaust temperature heat the carb then re-started and it was ok then that would be the explanation.

[jime17]

Is there oil in the dashpot?

How thick is it if so?

Does sound like you just pushed the choke on too soon though.

Edited by jime17, 26 January 2019 - 07:38 PM.

[Dusky]

Pumping the throttle doesnt do as much as on other cars, as the su doesnt have an accelerator pump.

[luismx123]

How old is the fuel? When was it last serviced?

fuel is from end of august when I parked it away. Been to a specialist to get the MOT here in Austria 3 weeks ago. Passed without any issues.

 

You sure you didn't just push the choke in too soon?

 

would be reason for it cutting out, not sure about the bogging part :/

Have you tried turning it off and then back on again ? lol

Being serious actually, I'm wondering if the carb iced. If you turned it off for 5 minutes and let the exhaust temperature heat the carb then re-started and it was ok then that would be the explanation.

im thinking the same to be honest. Ill give it a longer try tomorrow. what I dont understand is why sometimes when I pressed the accelerator it reved up smoothly, and other times it ended up having hickups and dropping revs

 

Is there oil in the dashpot?

How thick is it if so?

Does sound like you just pushed the choke on too soon though.

yea it does. was serviced 3 weeks ago. What you guys mean by that is let it warm up more on choke? I understand that heat/warmth makes things go better on the mini (especially when its minus degrees outside) but it doesnt explain the hit and miss style reving that I was having :/

I thought it could have to do with the dizzy, as its a new 123ignition dizzy but i was reving up to 5000 easily.... carb icing could definitely be a reason.,.. Ill give it a go tomorrow again and leave the choke on for 10min or so

[dyshipfakta]

Drive it on the choke for afew miles and put it in gradually. When it’s cold mine takes a couple of miles to come off of the choke completely

[DeadSquare]

The engine in your car was made to drive it along, not to be blipped.

 

Until engines are up to temperature, carburetors are known to have "flat spots", so what you are experiencing is nothing new, but "pumping" an SU , unlike a Webber, will not help, if anything it "confuses" the engine.

 

As you are pumping through a flat spot, what keeps the blipped engine going is the energy stored in the flywheel.  If the car is being driven, the energy of the moving car is added to that of the flywheel and this makes the flat spot hardly noticeable

 

Don't pull the choke out and leave it to soot up the plugs, a manual choke is just that, to be set manually as you best judge to adjust it.

 

May I suggest that today, you take a hair dryer and gently heat the carb until it feels nicely warm to the touch, before you start the engine, and then use it.

 

On the whole, cars in general prefer to be used rather than sat, forlorn. 

 

When my grandfather laid up his Rolls Royce during the last war, he was advised, among other things, to hand crank the engine 1/2 a revolution once a week.  In June 1945, he was instructed to prime the carburettor, fill the radiator with boiling water and wait 5 minutes before hand cranking 12 times.

 

The engine started at a touch of the "Electric Re-commencer"

Edited by DeadSquare, 27 January 2019 - 05:32 PM.

[luismx123]

The engine in your car was made to drive it along, not to be blipped.

 

Until engines are up to temperature, carburetors are known to have "flat spots", so what you are experiencing is nothing new, but "pumping" an SU , unlike a Webber, will not help, if anything it "confuses" the engine.

 

As you are pumping through a flat spot, what keeps the blipped engine going is the energy stored in the flywheel.  If the car is being driven, the energy of the moving car is added to that of the flywheel and this makes the flat spot hardly noticeable

 

Don't pull the choke out and leave it to soot up the plugs, a manual choke is just that, to be set manually as you best judge to adjust it.

 

May I suggest that today, you take a hair dryer and gently heat the carb until it feels nicely warm to the touch, before you start the engine, and then use it.

 

On the whole, cars in general prefer to be used rather than sat, forlorn. 

 

When my grandfather laid up his Rolls Royce during the last war, he was advised, among other things, to hand crank the engine 1/2 a revolution once a week.  In June 1945, he was instructed to prime the carburettor, fill the radiator with boiling water and wait 5 minutes before hand cranking 12 times.

 

The engine started at a touch of the "Electric Re-commencer"

Not sure if I explained properly. I "pumped" the gas pedal to rev the engine like at a traffic light when two people want to race. Not sure if thats what you understand or if i understand something different

Why does the choke soot up the plug? doesnt it just let more gas in? Is there a "limit" as to how long to keep it under choke to warm up? Im thinking out loud here, but doesnt it make sense to increase the idle rpms a touch during colder months?

Unfortunately I didnt get around to starting it yesterday. Got caught up ripping out the carpets :/

 

hahaha yea thats why I want to get the motor running some during these cold months. Its my first carb'd car and only have it since the end of summer last year. Havn't put it through a winter yet so just trying to figure it out :)

[cal844]

I run the same oil etc in the carb and engine year round, I don't alter anything from summer to winter once it's set up

[dyshipfakta]

The only limit on how long it takes on the choke is how Cold it is outside. Once the temps are in the right place choke can go in and happy days. It’s a gradual thing not an on or off. If you have pushed it in to early or too far it bogs.

Edited by dyshipfakta, 28 January 2019 - 11:33 AM.

[jime17]

The choke soots up the plug because the mixture is too rich for the air fuel mixture to burn fully. The by product of this is soot.

You need the choke in varying degrees for at varying levels until the engine warms up properly as has been said by others.

If you push the choke in before the engine is warm enough it will often idle well enough but as soon as you try to rev it or out load on it ie. Try to pull away it will bog down.

[DeadSquare]

Pumping,'regular', and Blipping, 'occasional', depressions of the exhilarator pedal seem to be examples of English being divided by a common language.

 

BUT

 

"Bogging down"

 

The "bog" is somewhere to take a crap,   ...   ..   Classic Minis are anything but crap !

 

 

 

 

Lol.

[nicklouse]

icing of the carb forget it you were not going any where and it was no where near cold enough.