Project 1974 MGB GT - The Mustard (Mit) Mobility Scooter - 6yrs ownership & the end is potentially nigh!

[tooSavvy]

Head in lions mouth... Ouch!!?

 

Might the car be 'given to' a [suitably old person/old skool] mechanic... For beer tokens/all our yesterdays craic... and have it caressed by someone who just 'knows the B' and can do (as has been said earlier) cigarette packet card adjustments - knows the rattles - feels tuning when it is 'in the zone'??

 

The 1000pound RR this is not >> look where he has ended up though!

 

Food For Thought

 

2centz, from someone who did IMPs

 

 

ATB m8

 

 

TS

[SiC]

Oh, come on people ! MGBs are as simple as a post-war car can get ; you don't need to be a professor of automotive engineering to get them to run properly !

 

There isn't much to the poor, old SUs, either. Problems are usually due to lack of use or people fiddling with them without knowing what they're doing.

 

SiC, I'd make sure everything on the ignition side is correctly set up first. Then, I'd take the SUs off to give them a quick clean. There are a million how-to articles and videos on this online. Then put them back on, make sure the linkage is installed correctly, and do a basic re-tune of idle and mixture. You then need to drive the car around a fair bit and make further adjustments at the roadside, until the thing runs well.

One thing I haven't mentioned is that I went to the Beaulieu Autojumble this year on the Sunday when it was pee'ing it down. The significance of that? Well I went to the SU stand for some gaskets. They didn't have the ones I needed individually - only as part of a set that included a float valve. As I was rather wet and fed up at this point I said I'd take them not quite expecting to having to need them.

 

So I have a pair of new SU gaskets and float valves. As I have them to hand, I guess it's probably worth cleaning it up in there and replacing them.

 

 

Re the pressure relief valve, undo the big nut and if the plunger and spring come out on their own accord, it's ok. Problems start when a bit of grit sticks the valve in the bore, leading to most of the pump's oil going straight down the overpressure drilling, and not up to the top of the engine.

Good call. I didn't know about this. Someone did remark earlier in this thread when I took the rocker cover off that it looked a bit dry up there.

[SiC]

Not completely clear from this pic, but the number 4 is wet. Number 1 is dry but lost its biscuit brown colour. Number 4 and 3 have always been black. 1 and 2 were brown.

 

Possibly is a sticking float. Going to remove carbs now. If sticking float it could have been like it for ages, just the new stronger pump has made it an issue?

 

[SiC]

Plug 2 is soaking too. Not sure I can read too much into this as I did keep trying to restart it.

 

Going to try doing a quick start before I go any further. Then carbs and oil change.

 

Oil is black but ok level. Doesn't smell of petrol. At least not strongly. My nose isn't that good...

[Mally]

Stick a 2.0 zetec in.....

 

Sent from my SM-A510F using Tapatalk

 

If anyone has a Blacktop for sale I am on the lookout.

[SiC]

Trying to fire and the occasional backfire but nothing.

 

Two carbs. Fiddler than I expected to remove.

 

Just realised I've run out of carb cleaner.

[Angrydicky]

You should get a Powerspark leccy ignition on if you haven't already. It has improved the reliability of my A40 Somerset no end

[SiC]

FFS. This is why I never became a mechanic and why my dad quit doing it. I even bought a proper scraper. Just clumsy.

 

Went to the bone too, so a bit sore.

 

[richardmorris]

Stitches?

Or at least some steri strips?

[Skizzer]

Ouch.

 

All carburettors are bastards, in my (very uneducated) experience.

[Mally]

Forget it until next year.

Then Roffle it £1 a go.

Probably not sell them all.

 

Oh and that is not an Engineers scraper.

[Mally]

Having read that again it sounds harsh. 

Sorry, not the way it was intended.

[SiC]

Having read that again it sounds harsh.

Sorry, not the way it was intended.

Don't worry I'm tempted right now! Frustrated but also determined that 1960s-1970s British will not beat me.

 

I probably need some sitches, but can't find any and can't be bothered. But never mind, a Elastoplast is mostly keeping it in and are the only plasters I'll consider nowadays. One the few plasters that don't fall off when they look at a bit of moisture.

 

Anyhow, less of my accidents and more of this carb.

 

Float chambers look fine to me and no gumminess or sticking. Both floats float fine too. I did notice one of the needle valves had a black spec on the seat. Not sure if that fell in when cleaning the chamber or if there all along. It should be clean though as there is a filter. The jets though are different colours. Not sure if they're different or not. I don't really want to remove them as I'll have to retune the carbs. In their current state and tune I know the engine can run at least.

 

Really irritatingly it appears that I've been supplied with two of the same floats. But one carb needs the inverse. I'll swap the front carb float and leave the back the same.

 

I've also set the float height using a good old Johnathan Twist video guide.

[Video]

[SiC]

Well this is rubbish. Originals don't stick.

 

[Video]

[320touring]

Is it sticking or is it a super weak spring? Doesn't look as bouncy as the one in the setting video

[SiC]

I've been fiddling with it and I think I agree. The spring isn't as strong as the other one. When it bounces, it has a habit of settling in a different place.

 

If it does stick though, putting it the right way up frees it off. I can't get it to stick when the correct way up.

 

A full rebuild kit might be on the January sales shopping list.

[Guest Hooli]

Tune the damn things. I bet they are running different mixtures, so just putting them to their base setting would improve matters.

[SiC]

I will do once I've got the friggin thing actually running by itself first! Will leaving the spark plugs out overnight help clear any flooding in the engine?

 

I've checked the spark and it's definitely happening. I'll double check static timing tomorrow.

[Guest Hooli]

Oh oil - sniff the dipstick, if it doesn't smell of petrol then you don't have a sump full of petrol.

[Guest Hooli]

Quickest way to clear the cylinders if it's well flooded is to spin it on the starter with the plugs out. But I'd lay a cloth across the holes first.

[busmansholiday]

Twin carbs are a twat to sort, but make sure when you stick them back on you put some grease on all the gaskets ( I was brought up with making gaskets out of cornflake boxes and a smear and of grease) as any air leaks will totally fuck up any work you do and are an absolute pig to track down.

 

If it's any help, proper old cars sense what you are thinking so if you take the attitude that it's going to go to rat shit it will. Get in, tap the dash, say, "Hello lovely, we're off to piss off all these modern piles of shite by getting from a to b without any problems and faster than them".

 

 

 

Usually works for me.....

[SiC]

I couldn't smell petrol in there but my sense of smell is crap. I'm going to do a change anyway once right after I've got it running. Plugs were wet and kept getting wet, so must be flooded. So wet that the carbon came off when I wiped them.

[Rusty_Rocket]

That's not good, those 'stay up' floats are supposed to be the best things in the world according to the SU website..  The springy action comes from the needle valve though doesn't it?  They are critical to stop the carbs flooding, are they in good condition and sealing properly in their seats?

[SiC]

They do seem to unjam when the carb is the right way up. I suspect the springs in the needle valve aren't as good as they should be. The back carb I filled with fuel and I saw no bubbles or fuel leak out of the inlet.

[Guest Hooli]

Btw, all those people saying twin carbs are a twat to setup must make hard work of it. I never found it a problem on my Midget or on my Bonnie.

[SiC]

The seats don't look to bad. This is the front that I'm currently working on.

[Rusty_Rocket]

It looks ok.  I would say though, if you suspect carb flooding problems, change the needle and its seat straight before anything else.  A weak valve, pitted seat etc will bring the whole system to its knees.   

[Rusty_Rocket]

Yes... problems magnified because you now have a good/ enthusiastic fuel pump?  Did you say it always ticks fast, as opposed to slowing down as it pressurises (a healthy) system?

[bigstraight6]

Btw, all those people saying twin carbs are a twat to setup must make hard work of it. I never found it a problem on my Midget or on my Bonnie.

Try it with twin Strombergs, they really are the work of the devil. I’ve owned my Stromberg inflicted Triumph 2000 for over 5 years now and after many hours of carb adjusting it’s still not quite right. I’m looking for SU replacements which these days seem hard to find and expensive, they are much better than Strombergs....

[SiC]

I think the seat and needle look fucked.

 

The seat appears to be full of pits and the needle has a clear ridge on it. That is wrong and fucked.

 

Ben

I think you might be right. The silver in the picture might just be the flash reflecting. Here is a picture without the flash.

 

It doesn't seem to leak when filled with fuel.

[Video]

 

However under pressure, it might be a different case. With the ignition on, I get a pump roughly every 20 to 30 seconds (I think). I always assumed that was it just building pressure up again. When I turn the ignition on at the start of the day, I do get a lot of pumps before it's ready. The filter has always been empty since I started having trouble. Originally when I bought it, it kept fuel in the filter. As I had a new pump, I wasn't sure if it was simply the new pump design leaking back to the tank. However it might be that the carb float chambers leak out of the bottom - one had signs of wetness at the bottom. They've got new rubber seals so hopefully that's sorted.

 

I'm really convinced it must be the carbs. If it isn't, I really don't know what else it could be. Unless it's a heat soak issue and because I flooded it when trying to get it to start again, I ended up with another problem.

 

I've left the plugs out and the carbs off over night. Hopefully any fuel in there will vapourise and clear the flooding. That's my hope anyway. I'll try giving it a start tomorrow too with no carbs on to be sure it's all cleared through.