After Dave's Toshi 975 suggested it I've removed a spare top to a 28IMB carb. This one appears to be a genuine Weber as it comes off an untouched 652 engine. You can see the detail of the bypass arrangement and the tapered seat, brass filter access screw. This is the filter that should remove any speck of dirt that has evaded any other filters in the system, but after it's been through my ultrasonic cleaner (a bowl of white spirit and a toothbrush ), and been looked at closely, it has been twisted resulting in a split....now in the bin.

That is a shame , I have never seen one with a split before. Have you got a replacement? I would pull out the brass ferrules before the dustman comes, they sometimes come in handy. Message me if you have not got another spare

Toshi 975 said:

That is a shame , I have never seen one with a split before. Have you got a replacement? I would pull out the brass ferrules before the dustman comes, they sometimes come in handy. Message me if you have not got another spare

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..that's very kind of you (as usual). The split is in the plastic fillter-basket.. you had to look very close to see it. The carb top itself is good apart from where the centrally placed elbow-screw has been driven slightly through what appears to have been a blind tapping; no big deal with a bit of threadlock to be certain.

It's going to work fine. thanks again for the suggestion.

Oh that little bit, I thought you were talking about the casting
I have got a few carb bits including one with the brass mesh if you should need it.

I think most of the engine running-in has been completed today; ....185 miles of high roads and by-roads, much of it between 30 and 40mph and some forays as high as 50mph. There was a bit of vapour lock early in the day when I stopped at the garage to fill up and there were a couple of awkward episodes later. But things settled down by the end of the day although the combination of a tight engine and high air temperatures did make for an uncomfortably warm experience.

I haven't used top speed or highest revs yet for obvious reasons, but the engine seems to have plenty of reserve power and is very smooth when running at a steady speed in traffic.

This was the furthest we have been for many months and it was good to see other classic cars and lots of motorbikes on the tourist roads of The Highlands.

After our long drive yesterday I thought it was worth checking all the settings. A new engine is bound to settle a little.

The fan belt needed tightening, the tappets were all a bit tight, I'd roughly adjusted the points gap during the day and they were too wide. I also topped up the oil and fitted the new plugs which had previously gone AWOL. [emoji16]

The contact breaker assembly is a mystery. I couldn't achieve my version of the old illuminating bulb technique to set the initial timing (I use a continuity tester). On investigation I could see that the pivot bush, which should be made of an insulated fibre compound, was made of steel. So despite having done many miles on this setup, in theory it shouldn't have worked; there should have been an insulated washer under the pivot. So I used a genuine, old set, smoothed on a flat diamond stone, cleaned and adjusted followed by dynamic timing with the strobe.

All of the maladjustments will have contributed towards overheating and the engine now runs better than ever. I even adjusted the mixture and idle and find it possible to get this extremely fine-tuned.

Murf's a happy little car today and ready for a 30 mile drive

I'm back to hogging the forum.

We covered a few more miles today up and down Loch Ness. So we're up to 300 miles on the "new" engine and it's running like a dream and doing about 55mpg.

I tried to avoid offending anyone by cropping the reversing light but unfortunately, the very wide angle lense I use makes Murf's bum look big in this.

We are very high up above Loch Ness on a private estate where you can often see RAF fighter jets travelling several hundred feet below your eye-level.

My mileage is well down on previous years for obvious reasons. My job isn't yet back up to speed and as winter approaches i'm less inclined to go the long distances anyway. So I'm still not quite up to 500 miles on the new engine when I will change the 20W50 running-in oil to my normal 10W50 motorbike oil. Today was so nice I decided to clock up a few miles close to home and obviously couldn't resist a photograph and one for Facebook too.

We did it again as in 2018.

https://www.fiatforum.com/500-classic/422579-murphios-meanderings-38.html?p=4360904

I've made my way through the whole thread over the past week or so, it's lovely to see old cars being used an enjoyed.

And I've got to say it makes me more keen to go and see the north of Scotland than ever before, that scenery is stunning! I've only been to Scotland once, I flew in to Glasgow on a damp January morning, did a days work and flew out at the end of the day, not really a fair representation of the country!

Goldnrust said:

, it's lovely to see old cars being used an enjoyed.

And I've got to say it makes me more keen to go and see the north of Scotland than ever before

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It's even better to be the one who's actually using the old car.

If you choose your time of year and destinations well, The Scottish Highlands is an incredibly scenic place, even if you never get out of the car.

Today I did my longest journey since March, covering over 180 miles and doing one stretch of seventy-five miles literally non-stop and at speeds of 50+ mph.

The 594 engine is well up to the task of hauling the car up steep hills and having set the 123 ignition to advance the timing a bit, that performance comes at a bit of a cost to fuel consumption which is just over 50mpg....the previous 650 did about 55mpg. One noticeable improvement is that on over-run, down very steep hills, I don't get the popping sound which used to really annoy me.

For some reason, although the locknuts are tight, the clutch-cable somehow ended up a bit tight and I could hear the release bearing running on the pressure-plate springs at tickover. A quick running adjustment on a beautiful dry, smooth road in the middle of nowhere soon sorted that out.

Here's what Murf looks like on the Axel Gerstl calendar and another standard photo of him posing in The Highlands.

On the best day that we've had for weeks, we trekked over to a lovely place with a lovely name; Jemimaville on the Black Isle. This is a few miles from Cromarty, where there are clear views across the firth towards Nigg. Nigg has a huge construction yard where the access to very deep water makes it a good place for the manufacture and servicing of oil-rigs.

The day took the total mileage on the new engine over 1,000, so I think I can now be certain that it's a reliable lump. There are no oil leaks and there have been no issues other than a bit of carburettor tweaking needed. The original intention was to try to sell it on at this stage. As previously discussed, that was likely to have been difficult and not cost effective. But in any case, I'm so pleased with it that it will be staying in the car for an indefinite length of time.

The 594 is hardly any different in acceleration and top speed from the 650. It comfortably cruises at 60 and has plenty of reserve. Where it is better than the 650 is in being more flexible in the gears. It will coast down from high speed when approaching a 30-zone without pushing me to immediately change down. It will pick up better when I need to do the opposite of that and I'm still in a gear which is technically a bit too high. As with the standard engine and the 650, it's actually still better in third when travelling in town or on undulating rural lanes.

Here's hoping for improved chances for long journeys in 2021...it's not looking too promising just now.:bang:

Mighty Murf has managed more meanderings of late. So much so that I think I have "Tiered" him out.

On the previous journey I was sensing a knocking on starting and aometimes on acceleration. It all fitted with the fan being loose again, but after taking off the intake hose and locking the alternator pulley I couldn't achieve any more movement of the super-Loctited nut.:bang: Whilst it was in pieces I removed a pulley spacer to tighten the fanbelt. Further prodding with a crowbar showed that one of the gearbox rubbers had come away from the steel mounting..the real cause of the knock. Half an hour later, a good, pre-used one was fitted.

There has been an increasingly worrying leak from below one of the big driveshaft rubber boots. Cleaning it up revealed that it wasn't the seal or the big "O"-ring which goes under the bearing housing, but was actually dripping from between the rubber and that housing . As a stop-gap, I drained the oil, removed the boot, cleaned it all up and put a bead of high quality RTV sealant on the edge of the boot and then clamped it all back in tightly. Those gaiters have a hard life and are under strain from day one; I hope I can find some really good ones to replace it.

Having bought some EP90 oil for my spare steering-box, I thought it wise to check the level on Murf. Surprisingly, it was still fully up to level after five years' driving .

After all these little jobs had taken up the bulk of the few daylight hours we have at the moment, I reflected on the fact that it does actually require you to keep a very close eye on these cars and put in the graft if you want them to run reliably.

fiat500 said:

Further prodding with a crowbar showed that one of the gearbox rubbers had come away from the steel mounting..the real cause of the knock. Half an hour later, a good, pre-used one was fitted.

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Of the 4 I have laying around, only one seems to be in what I would deem "good" condition. These seem like a less-than-ideal design. Have you, or anyone else, seen a polyurethane one that might be a bit more rugged?

JumpJet said:

Of the 4 I have laying around, only one seems to be in what I would deem "good" condition. These seem like a less-than-ideal design. Have you, or anyone else, seen a polyurethane one that might be a bit more rugged?

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I've been searching the 'net all evening. This is one part where the repros are actually quite good. As you say...less than ideal design. The later 126 BIS tried to improve on it with oversized, circular mountings. But in my experience, these were no more reliable. They are very expensive for anyone who wanted to experiment.

With regard to your drive-shaft boot oil leak Peter, i usually buy the 'top-quality' boots from Mark at Motobambino. These come with an alloy shaft-seal holder and I then replace the seal with a SKF silicon radial-shaft seal. Maybe I have been lucky, but i have never suffered much of an oil leak by doing it this way (I know, famous last words!)

the hobbler said:

With regard to your drive-shaft boot oil leak Peter, i usually buy the 'top-quality' boots from Mark at Motobambino. These come with an alloy shaft-seal holder and I then replace the seal with a SKF silicon radial-shaft seal. Maybe I have been lucky, but i have never suffered much of an oil leak by doing it this way (I know, famous last words!)

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Thanks Tom, I've sourced one, genuine, Fiat boot from eBay and will keep looking for more. The ones I have on the car already are the best, upcycled originals from my spare parts gearboxes. They are significantly more robust than the aftermarket ones I have had previously, but I will try Motobambino eventually.

I note that your recommended "Viton" seals can now be bought on eBay and there is also someone selling original Fiat seals at the moment. I did about 180 miles today and the leak is completely sealed for the moment.

.....and that 180 miles wasn't without its dramas. It's not always plain-sailing with Murf.

On a few occasions recently there have been moments when it has seemed that the car has momentarily run short of petrol. The circumstances have been when I'm at sustained speed, especially on undulating roads. I had investigated float levels and confirmed a good supply of fuel from the pump. Things had settled, but today I had a couple of times where the engine was hard to start after a short stop....classic fuel vaporisation. It wasn't a cold winter day, but it didn't seem warm enough to cause that sort of issue. After one short stop, and having got going again, the engine gave up halfway across the very long, Dornoch Bridge on the A9. This forced us onto a very narrow strip at the side, whilst lorries hurtled past at top speed.

It was going dark and threatening rain. I investigated and found a good spark, but with obviously overheated plugs. The mixture screw was out by two full turns; I randomly turned it to one and a half. As it's easy to get at, I also removed the idle jet and blew though it. The split at the end, which keeps it wedged in place, was flattened and needed opening out. With everything back in place it started first time.

I restricted the car to around 50mph for the rest of the 60 miles home, which was wise for the other reason, which was that by then, I was driving in rush-hour traffic in torrential rain.

More investigation is needed because I had another jittery moment only a few hundered metres from home. I may put the 123 back to its standard setting just in case I'm pushing the engine a bit hard. The main thing is, we got back in one piece, as usual.

I have suffered a similar problem Peter---turned out to be a tiny piece of 'something' sitting in ther bottom of the float chamber, and it was being pulled down into the jet, just enough to partly block it. It didn't do it all the time and was therefore a bit of a bugger to sort.