10 replies to this topic

[Kombi]

Model: Mini 1000
Year: 1971

I took my '71 Mini out for a spin today to run some errands. As I was climbing the hill out of town it started losing power rapidly while in fourth. Shifting down helped, but even in third it was losing power. Climbing this hill and even accelerating on it has previously never been an issue.

The only thing that I've done recently was to add about an ounce (30 ml) of Redline lead substitute to the fuel tank (5 gal/19 litre). I had no reason to believe the head on my 998 engine is set up for unleaded fuel which was what prompted me to add it in the first place. I really didn't want to cause any more damage by running unleaded. I could have definitely been wrong about that and I suspect that's the culprit, but I don't really understand why.

It runs okay on flat ground, but I do sense the acceleration in general isn't quite as strong right now.

All that said, I'm open to suggestions that there might be other things to check besides waiting for a few tanks of gas to run through. Your help and advice would be greatly appreciated.

Edited by Kombi, 25 November 2009 - 10:26 PM.

[taffy1967]

As long as 30ml was the correct mix/ratio then that won't be an issue. Even if it has been converted, the additive won't do any harm, not unless you use far too much and then the pistons (or whatever) can stick.

Try putting some fresh engine oil (or whatever you prefer using) in the carburettor dashpot.

Also check the electrics are in good shape and you're not running on 3 cylinders.

[Kombi]

Thank you kindly for the advice. That's good to know that the Lead won't cause harm either way, at least that can be ruled out.

I'll take a look at the dashpot, and check the spark to make sure everything is up to snuff there.

[jmetal88]

Yeah, when my Mini started doing that it was a weak spark, sorted out by installing new points and condenser.

I still loose about 5 miles per hour going up hills in 4th (depending on the grade), but I don't loose any in 3rd anymore.

[biggles1293]

Yeah, when my Mini started doing that it was a weak spark, sorted out by installing new points and condenser.

I still loose about 5 miles per hour going up hills in 4th (depending on the grade), but I don't loose any in 3rd anymore.

I had the same issues, was a right pain, I recently had the car rolling roaded and gained an extra 18bhp!! A lot of it was down to the needle in the carb - when that was changed the rolling road guy said it made a huge difference, and it certainly has, the top end before was around 85mph, 90mph at a push, she now loses puff at around 110mph, done on a private runway obviously ;o)

[Moke boy]

Sorry to change the topic, but which Rolling Road did you
use in Devon. I heard some conflicting reports !

Thanks

David

[jmetal88]

Yeah, when my Mini started doing that it was a weak spark, sorted out by installing new points and condenser.

I still loose about 5 miles per hour going up hills in 4th (depending on the grade), but I don't loose any in 3rd anymore.

I had the same issues, was a right pain, I recently had the car rolling roaded and gained an extra 18bhp!! A lot of it was down to the needle in the carb - when that was changed the rolling road guy said it made a huge difference, and it certainly has, the top end before was around 85mph, 90mph at a push, she now loses puff at around 110mph, done on a private runway obviously ;o)

Wow! I wish I could have my car dyno tuned, but nobody within driving distance knows British cars (if I went to them all they could tell me is what my car can do currently, not actually tune it), so all I can do is make a best guess.

[m1tch]

Hi there, I had power loss issues with hills, found out it was a kinked fuel hose causing insufficent fuel flow to the carb due to the extra fuel demand and the angle of the engine and carb, might be worth checking the routing, I re-routed mine and it solved the problem

[Kombi]

Well I thought I had licked the problem of the loss of power, but it appeared to have come back today in the strangest way.

Since the problem occurred I replaced the old Bosch coil with a new Pertronix Flamethrower which is compatible with my Pertronix ignition module, bought new leads, spark plugs, a "premium" rotor, and new distributor cap. I also installed a new fuel filter as the old one was filthy.

So today I was heading down the highway at a fairly good pace through some curves on the highway. I'd been maintaining speed, but had to slow down briefly for another car. When I accelerated again the car seemed to not want to go any faster than 65 no matter how much throttle I gave it. Where previously it was making 70 without an issue. This too while I was going downhill.

So maybe it's a heat build-up issue? Any other advice will be appreciated.

[Wil_h]

I've had inconsistent running problems caused by dirt in the float bowl. Occasionally some debris would stick in the jet leaning out the mixture.

Stripping the carb and liberal amounts of carb cleaner may help.

[Kombi]

I've had inconsistent running problems caused by dirt in the float bowl. Occasionally some debris would stick in the jet leaning out the mixture.

Stripping the carb and liberal amounts of carb cleaner may help.

That could be the next step then. When I purchased the car the owner said the carb had been rebuilt, but didn't say how long ago. I'll put that on the list.

I'd love to have the car dyno'd (rolling road), but I'm not sure there's any places local to me that are familiar enough with Mini's and have this facility. I may have to seek out the local Mini Club.