Project Rusty Triumphs in Scotland - Carbs, again - 17/02/25

[captain_70s]

Man the sun still sets fast at this time of  year...

Anyways, first things first. I checked the bulb for the 740's battery warning light.

It's fine, illuminates with the ignition on but goes out when the car starts, connections to the alternator are fine, it isn't noisy. Assuming voltage regulator/bushing failure.

I set it aside as I'd like a functional car for the weekend, have no parts for the Volvo and have limited daylight...

Threw carbs at the Acclaim.

It runs, after a fashion. It'll still only idle on choke, although it isn't dying as soon as it drops under 1,500rpm like it was before.

You can drop it right down to 800rpm but it chuffs away like it's runing too rich.

Something definitely isn't quite right, I'll play about with the choke/throttle stops in daylight. Once you're driving it's fine, as seems to always be the case with the Acclaim...

[GingerNuttz]

On 07/02/2025 at 20:48, captain_70s said:

Man the sun still sets fast at this time of  year...

Anyways, first things first. I checked the bulb for the 740's battery warning light.

It's fine, illuminates with the ignition on but goes out when the car starts, connections to the alternator are fine, it isn't noisy. Assuming voltage regulator/bushing failure.

I set it aside as I'd like a functional car for the weekend, have no parts for the Volvo and have limited daylight...

Threw carbs at the Acclaim.

It runs, after a fashion. It'll still only idle on choke, although it isn't dying as soon as it drops under 1,500rpm like it was before.

You can drop it right down to 800rpm but it chuffs away like it's runing too rich.

Something definitely isn't quite right, I'll play about with the choke/throttle stops in daylight. Once you're driving it's fine, as seems to always be the case with the Acclaim...

These should have pilot jets yank so em out and blow through em with compressed air or replace em.

I had some bother with the pilot jets blocking until I put a better fuel filter in it the Herald so if you have a see through plastic filter before these remove it and fit a canned fuel filter under the car at the tank, makes a huge diff.

Pilots are for tick over up to 30% throttle on Keihin carbs so it might be your issue.

[captain_70s]

4 hours ago, GingerNuttz said:

These should have pilot jets yank so em out and blow through em with compressed air or replace em.

I had some bother with the pilot jets blocking until I put a better fuel filter in it the Herald so if you have a see through plastic filter before these remove it and fit a canned fuel filter under the car at the tank, makes a huge diff.

Pilots are for tick over up to 30% throttle on Keihin carbs so it might be your issue.

It was deffo the pilot jets before, it had the same problem a year ago. I'm gonna stick a canned filter back by the tank, @juular has offered one from his stock.

Went back out to it in the daylight, tried to start it, wouldn't start. Popping through the carb, generally being a piece of shit.

Pulled the air filter housing off and found one loose vac hose and one which should have been blanked off but had lost it's cap. Replaced that shit, car fired up and ran perfectly. Took it a spin for a few miles, flawless.

2 hours later, need to run to the supermarket. Halfway there it starts spluttering under throttle.

Now though the problem has shifted. It idles perfectly, completely shits itself and seems to drop to two cylinders between 1,500 and 3,000rpm and then clears back up again if you force past it.

Rechecked the vac hoses, all good. Sprayed carb cleaner about the rubber mounting blocks and they seem fine. Either it's another blockage or a sticky piston. Shall pull it back apart over the weekend, I'm getting pretty fast at it now. 😂

Today I was messing about with the 740. Checked the continuity for the 3 wires that go to the alternator and they're all fine. Pulled the alternator.

As you can see it lives under the oil filter and in the path of the inevitable rocker cover gasket seepage.

There was evidence I was not the first person to have removed it...

The bushes were a decent length, online seems to suggest they can be nearly flush with the housing before they are totally dead.

I tested the resistance for the diodes and then rigged the alternator up to a battery and ran it off a drill for bench testing.

Completely dead. Will need to dig into it further. Don't get why the battery light in the car is going out, despite no charge, when my test light doesn't. 

I also finally sorted out the stuff that was recovered from Girlfriend_70's gran's shed.

The metal toolboxes were right underneath the hole in the roof.

The big cantilever one has actually rusted through on the bottom. Most of the contents will have to go in an acid based de-rusting solution of some description and we'll see what will actually be salvageable.

[captain_70s]

So, Acclaim carbs back off.

It seemed the RH piston was getting stuck. Using a screwdriver It'd rise slightly then stick then pop free. No oil damper on these, like an SU, just a weak return spring.

I also stripped both down completely and blasted everything through with carb cleaner. Again.

Reassembled and tried to lift the pistons with a screwdriver, both jammed solid. U wot m8?

Took the domes off, both pistons free to move in the carb body. Put the pistons in the domes, both free to move there too... Hm. There was some marking to the edges of the pistons so I polished them with wire wool.

Reassembled, one piston moved and then jammed, the other was stuck solid. Right, started removing the domes and as I loosened the screws I heard the jammed piston dropped back down.

It seems with the screws tightened the domes either don't centre properly on the carb body or are sitting at an angle and jamming the pistons. I tried rotating the domes 180 but the problem persisted.

I might have accidentally swapped the pistons/domes, which could potentially cause issues. Or I could have overtightened the domes previously and damaged the aluminium surface where the screws locate. Not sure.

Either way I just tightened the screws bit by bit until the pistons started getting resistance and then backed them off a touch. There is a rubber seal and it shouldn't be loose enough to vibrate itself looser.

Reassembled and went for a test drive, drives fine. No issues at all.

Perfect. With this in mind I have immobilised the car in a new way.

This is because the mobile tyre fitter is coming over tomorrow to replace these...

Which could be charitably described as "well used".

I prefer to remove/refit the wheels myself if possible, prevents squashed sills/chassis rails from being jacked up in the wrong place and means I can do the wheel nuts up to a torque which allows roadside removal in the case of a flat. 

@MrsJuular kindly volunteered to test the 740's alternator and found the bridge rectifier was fucked. Replacement was £130 odd from Europe so just bought a new alternator. 

Cadged a lift to an auction and didn't even come home with a car...

Some weird stuff is worth money these days...

There was a very shiny Inca Yellow Dolly 1850HL like my old one up for grabs. Up close there wasn't much right with it. Wonky sills welded to the front wings, evidence of rear wheelarch bodgery and wobbed door bottoms just at a glance. I think it went up to £5k odd, not sure if it made reserve though.

Obviously I went out to the work van this morning to find it sat in a puddle of oil...

This really isn't my problem but it'd be rude not to look...

Naturally, having been serviced last Tuesday, the sump plug was loose. Tightened it, drove to site and it was still dripping but with it hot I could get an extra 1/2 turn on it which seems to have stopped it.

The last time it was serviced they left a rear brake bleed nipple loose... As I discovered approaching a roundabout outside Redcar, downhill, off a dual carriageway, at speed.

And people wonder why I try to avoid having garages work on my cars...