Morris Minor Owners Club

Fitted a recon unleaded engine 3500 miles ago. Right from the start it ran rich and was "hunting", then over 2 weeks quickly deteriorated to chugging and backfiring and running hot and running on, took it into a local garage, points had closed and knocked timing out also carb was all over the joint cos of me fiddling with it whilst on my hols in an effort to make it driveable.
It was retarded to I think about 2-3 degrees as per instructions with engine. Anyway it drove better but was still running hot, overheating in traffic jams and running on spectacularly. Approaching it's 3500 mile service I bought new points, condensor, dizzy cap, oil, oil filter, air filter, ht leads, plugs, as well as flushing the rad and changing the coolant and the thermostat (old one was working by the way).
All these jobs done i was hoping it'd drive lovely, but to the gurning face on my new found mechanic who seems to know his moggies well enough to phone the engine supplier to discuss timing with him, it ran even hotter and with a dramatic loss of power when retarded to 2-3 degress. My mechanic had predicted this saying it'd be better advanced but then I'd have to use red ex. After a week of struggling on I've took it back to him, he's advanced it and it's running cooler, not running on (maybe a tiny bit) and has more poke. But it's still hunting worse than ever in fact. Idles like a bag of spanners. Have spoken to engine supplier and outlined this tale. His engineer reckons it needs a new rad. Whilst my mechanic reckons it's carb maybe sucking air in somewhere like inlet manifold and is going to start there, if neither of them things resolve it then it's new carb and dizzy time. Anyone have any experience of similar probs who could assist. BTW, my mechanic reckons even if we do cure hunting I shouldn't retard it back cos it'll still run on less power. Please help

Avoid this 'mechanic' like the plague - he hasn't a clue!! Advance the timing till it 'pinks' then take it back very slightly till no pinking. Also check if the vacuum advance is working - most are not if over 10 years old. He may be right about new rad - but first try a good flushing with drain cleaner (or Rad Flush) to get the temperature down. Was it actually boiling - or you just relying on a temp gauge ? Consider new plugs - I have just spent two days on a mate's poor running MGB engine - changed everything on the ignition side(dizzy/coil/cap/leads/rotor arm etc etc) /removed and cleaned/checked carbs - finally in desperation fitted a new set of plugs and VOILA - sorted. The NGK plugs that were in there were relatively new and looked fine - but were the cause of all the problem - we threw them as far away as possible into the field at back of his house !! Lesson learned - stick to Champion!

i would say do as BMC says about flushing the rad
i had teh same problem when i did drive over 60 so got some drain cleaner (demestos on offer at tesscos black bottle ) got teh car up to runningtemp then switched off added teh drain cleaner started teh engine left to run for about 1 hour screwed teh scew onteh carb so it ran faster then after a hour i let it get cold teh drained teh hole system .flushed teh engine at every point i could get teh hose in to ie pipes heater rad , and now i have found at 85 its fine drinks a bit of fuel as still timming to sort but at no can do.
befoer i did the flush the coolant was clean and blue no signs of any rust etc but now you can see a lot better and there was a lot of rusty water coming out after teh drain clean was added

To really flush the rad you need to take it out to back flush it and its surprising how much extra muck comes out even just using a hose.

Hi JohnPaul

Sorry you're having problems. Don't get mixed up between advanced and retarded. The engine will run hot if retarded, i.e fires AFTER TDC...It should be advanced to fire 3 to 5 degrees BEFORE TDC.

Do as BMC says, his advice is excellent. perhaps a compression test too? Yes, and find another mechanic!!

I'd also suggest thet you add your location to your profile, so people can see where you are. If you were close to where i live in Suffolk, i would gladly come and have a look at a weekend, as I am sure a lot of people on the forum would be...

Don't struggle on on your own ppl here are always keen to help

thats true dave i will help if you are near to the suffolk norfolk boarder but be paition with me as im off and on here at moment as my new born is in the hospitail and due to the problems he has got we are there 24 7
good luck let me know were you are

Thanks for your help. I'm in New Brighton on the Wirral, up north. Boooo. It is advanced to about 8 now and is driving really nicely. When it was retarded to 2-3 as per unleaded engine spec it was slow and overheating loads, running on and that. Just to clarify, the mechanic I've spoken to advised this new timing whilst the engine supplier advised flushing the rad and sticking with 2-3 degrees. It's defo not running hot now but still humpty dumpty idling. Whats TDC?

Top dead centre - when the piston's as close as it gets to the cylinder head.

I'm getting it I think. Ta for my help

It may not just be the radiator that's choked up - I recently opened a 1275 and almost ALL the passages between block and head were blocked with thick hard goo. So I suggest flushing the complete engine and radiator with drain cleaner - but only leave it in there for an hour - then drain and refill with water. If it stays clean - all is well - if it colours up - then repeat the drain cleaner!!

When it was retarded to 2-3 as per unleaded engine spec it was slow and overheating loads, running on and that.

I thind DaveC hit the nail on the head, the instructions probably said to start by retarding by 2 - 3 degrees from your normal setting and not set at 2 - 3 degrees retarded, still it looks like things are sorted now.