Tuning Carb base leak

[bugsymike]

Sorry to hear still not running right.
Little concerned that it starts OK, then worse when getting warmed up.
If as has been suggested it improved with easing choke out a little that could point to carb running weak.
However my other thoughts return to valves sticking in guides or not sealing/burnt out.
Others may advise better , but is there any issues re running unleaded modern fuels on these engines if valve seats haven't been modified. I know on Ladas with aluminium cylinder heads it wasn't a problem as they had been designed to run on anything the Russians threw at them.
Re direction of distributor, I don't know off hand, but usually able to tell by the advance bob weights allow more movement in the correct direction as they try to advance when twisting the rotor slightly, otherwise check at crank pulley by marking it and flicking ignition key a little, then knowing that turn engine at pulley and watch rotor. Simple tests like that help if you work on many different makes of vehicle, as I did from day one. I had friends who trained at Ford or Vauxhall for example who were great on those vehicles, but knew very little if you gave them another make to work on.
I trained at a country garage and the same day you could work on a 1950s XK Jag, the bosses boat engine, a farm tractor or be welding an old ladies shopping trolley for her. Oh! also punctures on muck spreaders.

 

[FR85]

Sorry to hear still not running right.
Little concerned that it starts OK, then worse when getting warmed up.
If as has been suggested it improved with easing choke out a little that could point to carb running weak.
However my other thoughts return to valves sticking in guides or not sealing/burnt out.
Others may advise better , but is there any issues re running unleaded modern fuels on these engines if valve seats haven't been modified. I know on Ladas with aluminium cylinder heads it wasn't a problem as they had been designed to run on anything the Russians threw at them.
Re direction of distributor, I don't know off hand, but usually able to tell by the advance bob weights allow more movement in the correct direction as they try to advance when twisting the rotor slightly, otherwise check at crank pulley by marking it and flicking ignition key a little, then knowing that turn engine at pulley and watch rotor. Simple tests like that help if you work on many different makes of vehicle, as I did from day one. I had friends who trained at Ford or Vauxhall for example who were great on those vehicles, but knew very little if you gave them another make to work on.
I trained at a country garage and the same day you could work on a 1950s XK Jag, the bosses boat engine, a farm tractor or be welding an old ladies shopping trolley for her. Oh! also punctures on muck spreaders.

When it comes to unleaded I do run a lead additive along with an ethanol additive. I also have a bit of a belief that there should be an element of valve seat memory from previous runnings with leaded fuel.
I've heard of so many folks running additives and many others not and there have been minimal detrimental effects. Stand to be corrected.....

Given it's on its second carb with the same issues I'm thinking ignition timing, for it to be popping both ways and there being a shimmy back and forth on the strobe I could be getting both ends if the stick with some pre and post detonation.

I'm also thinking it could indeed be the after market exhaust which is just a slightly noisier single exit affair from either Axel Gerstl or Fd Ricambi, Abarth knock off vibe, nothing special.

 

[bugsymike]

When it comes to unleaded I do run a lead additive along with an ethanol additive. I also have a bit of a belief that there should be an element of valve seat memory from previous runnings with leaded fuel.
I've heard of so many folks running additives and many others not and there have been minimal detrimental effects. Stand to be corrected.....

Given it's on its second carb with the same issues I'm thinking ignition timing, for it to be popping both ways and there being a shimmy back and forth on the strobe I could be getting both ends if the stick with some pre and post detonation.

I'm also thinking it could indeed be the after market exhaust which is just a slightly noisier single exit affair from either Axel Gerstl or Fd Ricambi, Abarth knock off vibe, nothing special.

I tend to think unless vehicles have been designed to run on current fuels then the older ones were definitely happier with lead. I converted an old boat to diesel and the old 1982 five star petrol that, once I had drained the water and sediment out of I put in a Fiat Uno I was running and I can honestly say it was the best it had ever ran, that stale fuel was over 20 years old as boat had been standing in the yard all that time to my knowledge.
It would be nice to eliminate some things, at present you have changed carbs, electronic ignition to points, etc. and no massive improvement.
What is your instinct the problem, is from your point of view driving it?

 

[fiat500]

Evening!

Tonight's proceedings went as follows:
Old points back in (only about 150 miles since reverting back to points from an electronic ignition that failed)
New condenser, leads, cap and rotor.
Mixture screw all the way in and back out 3 turns, points set to about .5mm and confirmed to be happening with a test light.

Car started and it's noticeably more lively!
Ran it on choke for 5 minutes to bring the battery back around and eased off the choke, brought up the idle screw and have the mixture have a turn back in and it's idling nicely.
From the engine bay when it was warm I gave it a good rev, held it for 8 seconds and it started to fall and I'd to fettle the throttle to catch it and return it to idle. If I didn't do this it would just die, found this out the next time.
It's popping through the carb and there is still popping through the exhaust as it's falling.

I put a strobe on it set to around 12 degrees and while there is a slight wander through hunting, it's not a complete train smash.

I also remembered this carb has 125 jets in it, came off a running 600 126 engine.

Am I up against timing or fueling do we think?

Based on the info I've provided should the dizzy go clockwise or anti clockwise?

Sorry this thread has taken a turn but I didn't want to be creating lots of them and have answers and suggestions in a few different places!

Hope 24 is treating everyone kindly!

When you set it to 12 degrees, is that on idle?
I wouldn't worry about the idle degrees as long as it starts and ticks over OK. You need to check the degrees advance in the high range of RPM. This is where you are looking for that (circa) 28 degrees. If it's significantly less than that, you need to incrementally rotate the distributor anti-clockwise until it does.
If you can't achieve that or if that then messes up thes idle, it points to a possible fault wtin the distribtor advance.

 

[FR85]

I tend to think unless vehicles have been designed to run on current fuels then the older ones were definitely happier with lead. I converted an old boat to diesel and the old 1982 five star petrol that, once I had drained the water and sediment out of I put in a Fiat Uno I was running and I can honestly say it was the best it had ever ran, that stale fuel was over 20 years old as boat had been standing in the yard all that time to my knowledge.
It would be nice to eliminate some things, at present you have changed carbs, electronic ignition to points, etc. and no massive improvement.
What is your instinct the problem, is from your point of view driving it?

Did the fuel not varnish over the 20 years? I cleaned out a fuel tank from my 600d after it had been sitting for a similar duration and my lord the smell, it was lingering in the garage for weeks!
The only way I think I'll get leaded fuel is to run it on avgas, think that is the only true leaded fuel left?

To be honest the last time I was out it ran grand for a few miles albeit with the backfires when decelerating to a junction or similar then things got rough and like in my first post I discovered the base of the carb leaking after heat, fuel was bubbling outside from under the gasket so I thought with heat something is opening and drawing in air and possibly leaning up the mix.

So in essence this to a degree leaves me back at the very start, carb in theory has been changed with bakelite spacer, all the ignition stuff with the exception of nearly new points.
So now I think it's look at timing, see if I can stop it from falling down and possibly change back the original exhaust.
Back at the beginning I think!

 

[bugsymike]

Did the fuel not varnish over the 20 years? I cleaned out a fuel tank from my 600d after it had been sitting for a similar duration and my lord the smell, it was lingering in the garage for weeks!
The only way I think I'll get leaded fuel is to run it on avgas, think that is the only true leaded fuel left?

To be honest the last time I was out it ran grand for a few miles albeit with the backfires when decelerating to a junction or similar then things got rough and like in my first post I discovered the base of the carb leaking after heat, fuel was bubbling outside from under the gasket so I thought with heat something is opening and drawing in air and possibly leaning up the mix.

So in essence this to a degree leaves me back at the very start, carb in theory has been changed with bakelite spacer, all the ignition stuff with the exception of nearly new points.
So now I think it's look at timing, see if I can stop it from falling down and possibly change back the original exhaust.
Back at the beginning I think!

Fuel was fine, boat had belonged to my old boss before I went self employed and had been sat in his yard probably even before that. Original engine was a Volvo Penta 150Hp V6, which over all those years had rusted out all the raw water (sea water cooling) heat exchangers etc. and was knackered, fuel had been sitting in a galvanised tank under the floor ever since. I replaced tank with plastic one as diesel and galvanised don't mix. I did have to filter out a lot of sediment and water, but genuinely Fiat Uno loved it. Not much chance of Avgas unless you run an aeroplane
When I was into old motorbikes in the 1960s and even static engines the fuel could have been sat for years and would run, it is only the modern rubbish that goes so dead quickly.

 

[bugsymike]

Any clues re engine, after a run pulling spark plugs and seeing how they look?
Serious backfiring through the carb/inlet manifold I have only seen with burnt out or sticking valves not shutting/sealing and also back in the old days when manifolds had something called a "hot spot" which was used to warm the carb up from cold to stop icing etc. and on some vehicles could burn through allowing exhaust to get into inlet side.
If just a misfire and backfiring then ignition if timing way out or carb very lean/ weak due to serious airleak or blocked jets etc.
If idles reasonably but coughs and spits when accelerating, maybe the latter but if idling and spits back more likely valves etc.
But Heh! there is always something new we haven't thought about, it's a mechanical object.

 

[FR85]

When you set it to 12 degrees, is that on idle?
I wouldn't worry about the idle degrees as long as it starts and ticks over OK. You need to check the degrees advance in the high range of RPM. This is where you are looking for that (circa) 28 degrees. If it's significantly less than that, you need to incrementally rotate the distributor ant

When you set it to 12 degrees, is that on idle?
I wouldn't worry about the idle degrees as long as it starts and ticks over OK. You need to check the degrees advance in the high range of RPM. This is where you are looking for that (circa) 28 degrees. If it's significantly less than that, you need to incrementally rotate the distributor anti-clockwise until it does.
If you can't achieve that or if that then messes up thes idle, it points to a possible fault wtin the distribtor advance.

Sorry, typing off a phone, was supposed to be static set to about 12BTDC, at idle there wasn't too much flickering, I dont have the rev counter hooked up cause I didnt know if the coil would be coming back out. I've never used a strobe before so I was just having a play.
Will have another look at it tomorrow but I'm not sure I'll have enough hands to hold at around 3k revs, the gun and the cap.....I can already feel the burns off the exhaust!

 

[FR85]

Any clues re engine, after a run pulling spark plugs and seeing how they look?
Serious backfiring through the carb/inlet manifold I have only seen with burnt out or sticking valves not shutting/sealing and also back in the old days when manifolds had something called a "hot spot" which was used to warm the carb up from cold to stop icing etc. and on some vehicles could burn through allowing exhaust to get into inlet side.
If just a misfire and backfiring then ignition if timing way out or carb very lean/ weak due to serious airleak or blocked jets etc.
If idles reasonably but coughs and spits when accelerating, maybe the latter but if idling and spits back more likely valves etc.
But Heh! there is always something new we haven't thought about, it's a mechanical object.

I've set the ins to .20 and the outs to .25 using the rule of 5 from cold and when turning the engine over they're going up and down.
I don't have confidence or indeed the weather to go for a test drive but the last time I pulled the plugs to ease doing valves clearance they were a nice tanned colour with no oil or carbon. I might do a compression test on the cylinder 2, can't do 1 as someone in a previous life cross threaded the plug, drilled and helicoil'd it.
Maybe I'm not diagnosing it right, could be misfiring.
It's idling and it will rev so I don't think it's jets in the carb and the spacer and gaskets are all new so I don't think it's an air leak but I might get a can of "ether gogo" and spray it around the base to eliminate air leaks.

More playing needed, thanks all so much!

 

[bugsymike]

I've set the ins to .20 and the outs to .25 using the rule of 5 from cold and when turning the engine over they're going up and down.
I don't have confidence or indeed the weather to go for a test drive but the last time I pulled the plugs to ease doing valves clearance they were a nice tanned colour with no oil or carbon. I might do a compression test on the cylinder 2, can't do 1 as someone in a previous life cross threaded the plug, drilled and helicoil'd it.
Maybe I'm not diagnosing it right, could be misfiring.
It's idling and it will rev so I don't think it's jets in the carb and the spacer and gaskets are all new so I don't think it's an air leak but I might get a can of "ether gogo" and spray it around the base to eliminate air leaks.

More playing needed, thanks all so much!

Many use rule of "5" and other methods. Unless some peculiar engine, I do "on the rock" on the opposing cylinder and then do both valves at the same time on the one at TDC on it's firing stroke, as in No.1 inlet and exhaust valve adjust/check if rocking valves on No4 on a four cylinder engine. Some people will tell say that is wrong, but if it has worked for over 55 years on 2,4,6 and 8 cylinder engines then good enough for me. It is also quicker as involves less turning engine so doing two valves at the same time (obviously two feeler gauges out if different settings such as pre crossflow Fords 10 and 17 thou. but not A Series BMC both 12 thou, or B Series 15 Thou.
Though what ever method you use, as long as valves set at correct clearance, then which ever works for you.
Plugs sound good if nice light brown, newer designs tend to run much lighter for emission regs. etc.
If Helicoiled professionally then should be no problem with that repair. In the early 70s it was quite common to find No4 spark plug on things like small Renaults which had the very short reach plugs and that last one was fairly inaccessible by the bulkhead. I always tend to wind things in by hand as far as possible to eliminate issues like that.
If engine will keep idling, can you pull plug leads off one at a time to see if one cylinder working better than the other, honestly I am not trying to get you an electric shock.
If all else fails, seeing you have tried different carbs and ignition set ups then maybe a compression test followed by a "leak test" if you have the gear.

 

[FR85]

Many use rule of "5" and other methods. Unless some peculiar engine, I do "on the rock" on the opposing cylinder and then do both valves at the same time on the one at TDC on it's firing stroke, as in No.1 inlet and exhaust valve adjust/check if rocking valves on No4 on a four cylinder engine. Some people will tell say that is wrong, but if it has worked for over 55 years on 2,4,6 and 8 cylinder engines then good enough for me. It is also quicker as involves less turning engine so doing two valves at the same time (obviously two feeler gauges out if different settings such as pre crossflow Fords 10 and 17 thou. but not A Series BMC both 12 thou, or B Series 15 Thou.
Though what ever method you use, as long as valves set at correct clearance, then which ever works for you.
Plugs sound good if nice light brown, newer designs tend to run much lighter for emission regs. etc.
If Helicoiled professionally then should be no problem with that repair. In the early 70s it was quite common to find No4 spark plug on things like small Renaults which had the very short reach plugs and that last one was fairly inaccessible by the bulkhead. I always tend to wind things in by hand as far as possible to eliminate issues like that.
If engine will keep idling, can you pull plug leads off one at a time to see if one cylinder working better than the other, honestly I am not trying to get you an electric shock.
If all else fails, seeing you have tried different carbs and ignition set ups then maybe a compression test followed by a "leak test" if you have the gear.

I normally roll the engine over twice or three times when doing the valves and go through them to the best I can.

The helicoil reference was more so to do with doing a compression test and actually risking electric shock would be a good way to figure it I've a strong and weak cylinder.

Just need to find time to get out there again.... every time I suggest going out to the garage I get that look from herself, sometimes its just not worth it!

 

[bugsymike]

The helicoil reference was more so to do with doing a compression test and actually risking electric shock would be a good way to figure it I've a strong and weak cylinder.

Or a strong or a weak heart

 

[Goldnrust]

From the engine bay when it was warm I gave it a good rev, held it for 8 seconds and it started to fall and I'd to fettle the throttle to catch it and return it to idle. If I didn't do this it would just die, found this out the next time.

Once you had 'caught' the revs with the throttle, would it return to a nice stable idle? If its got a good stability idle, with your mixture screw at approx 2 turns out (you said you started with 3 and backed it down by 1 turn) then I don't think you can be looking at anything too drastically wrong with timing or too big an air leak.

Did you verify that it was up to full temp before doing this test of holding the revs up? Depending on the outside temps it might take longer than you think to really get the engine up to full temp just by idling it. You could try applying a touch of choke and see if that helps, if it gets worse its rich, if it gets better then it was lean, if just a bit of choke doesn't make much difference then it gets worse as you add more choke then its about right!

As you've now got a reasonable idle, I think a test drive would really help you, even if its 100 yards up the road and back, you'll learn more about what the engine is or isn't doing than free revving as thats not an especially realistic driving scenario for the carb.

 

[FR85]

Once you had 'caught' the revs with the throttle, would it return to a nice stable idle? If its got a good stability idle, with your mixture screw at approx 2 turns out (you said you started with 3 and backed it down by 1 turn) then I don't think you can be looking at anything too drastically wrong with timing or too big an air leak.

Did you verify that it was up to full temp before doing this test of holding the revs up? Depending on the outside temps it might take longer than you think to really get the engine up to full temp just by idling it. You could try applying a touch of choke and see if that helps, if it gets worse its rich, if it gets better then it was lean, if just a bit of choke doesn't make much difference then it gets worse as you add more choke then its about right!

As you've now got a reasonable idle, I think a test drive would really help you, even if its 100 yards up the road and back, you'll learn more about what the engine is or isn't doing than free revving as thats not an especially realistic driving scenario for the carb.

Hey,

When I'd catch and fettle it to stabilise it she'd idle as per normal.

I don't think it's an air leak at the carb anymore as it's have a new or change of everything at that end and holding a damp rag over the exhaust kills it.

I know it's not getting up to full full temperature as I've the boot lid off and Ireland has been sitting at -/+4 ish degrees on nights I've been working on it.

My issue with going for a drive is it not recovering from a rev or me not being able to catch it and then not being able to start it. I also need a dry day, I hate them seeing rain!
I do see what you mean about a real world test however so I'll have to brave it when the weather allows!

Thanks all!

 

[FR85]

Timing!

I did some fiddling with the distributor this evening and a slight twist anticlockwise brought it to life. Still some pops but the responsiveness is night and day. It's also running cooler, before the oil cap would be hot after a long idle/rev but now it's touchable.

I also discovered that there was a second return spring fitted to the carb throttle linkage. I wasn't getting full throttle and the amount of times I had the carb on and off fitting this spring just became second nature.
I'm going to try and bring the cable back to life with wd40 and oil everywhere link in the chain I can find.

Happier little bunny is FR85 tonight!! Still not 100% but I'd be confident now to bring it for a spin with tonight's results. I may tax it now!!

 

[the hobbler]

Evening!

Tonight's proceedings went as follows:
Old points back in (only about 150 miles since reverting back to points from an electronic ignition that failed)
New condenser, leads, cap and rotor.
Mixture screw all the way in and back out 3 turns, points set to about .5mm and confirmed to be happening with a test light.

Car started and it's noticeably more lively!
Ran it on choke for 5 minutes to bring the battery back around and eased off the choke, brought up the idle screw and have the mixture have a turn back in and it's idling nicely.
From the engine bay when it was warm I gave it a good rev, held it for 8 seconds and it started to fall and I'd to fettle the throttle to catch it and return it to idle. If I didn't do this it would just die, found this out the next time.
It's popping through the carb and there is still popping through the exhaust as it's falling.

I put a strobe on it set to around 12 degrees and while there is a slight wander through hunting, it's not a complete train smash.

I also remembered this carb has 125 jets in it, came off a running 600 126 engine.

Am I up against timing or fueling do we think?

Based on the info I've provided should the dizzy go clockwise or anti clockwise?

Sorry this thread has taken a turn but I didn't want to be creating lots of them and have answers and suggestions in a few different places!

Hope 24 is treating everyone kindly!

You turn the distributor clockwise to RETARD the timing , and anti-clockwise to ADVANCE the timing. The use of points allows one to "statically" time the distributor---a simple light for carrying out the static timing can be made from anything that can have a 12 volt bulb fitted and a couple of longish leads with small 'crock-clips' on each cable.

 

[bugsymike]

With modern fuels I find with older cars it's best to use the original timing marks as a starting point, then with engine warmed up check for any signs of "pinking" when pulling under load up a hill.
I definitely got a power boost in an old Fiat Uno some years ago when on fitting a diesel to a boat, I had some 1980s five star petrol which I filtered for water and dirt then tipped in the Uno, the difference was quite noticeable.

 

[the hobbler]

With modern fuels I find with older cars it's best to use the original timing marks as a starting point, then with engine warmed up check for any signs of "pinking" when pulling under load up a hill.
I definitely got a power boost in an old Fiat Uno some years ago when on fitting a diesel to a boat, I had some 1980s five star petrol which I filtered for water and dirt then tipped in the Uno, the difference was quite noticeable.

I have mentioned this before---in the bulk of England, (sadly with the exception of the West Country), according to Esso's own web-site, their Super 99+ petrol is ETHANOL FREE! I have found that this is the best fuel to use in the 'enhansed' 126 engine in my 500. However, I still put the recommended amount of "anti-ethanol" gunge in the petrol. A friend of mine has a 1200cc Ford Anglia ('Super' model)---following my suggestion, he also now puts this fuel into his car, reckons that it has made a definite improvement in the running of the engine.

 

[FR85]

I have mentioned this before---in the bulk of England, (sadly with the exception of the West Country), according to Esso's own web-site, their Super 99+ petrol is ETHANOL FREE! I have found that this is the best fuel to use in the 'enhansed' 126 engine in my 500. However, I still put the recommended amount of "anti-ethanol" gunge in the petrol. A friend of mine has a 1200cc Ford Anglia ('Super' model)---following my suggestion, he also now puts this fuel into his car, reckons that it has made a definite improvement in the running of the engine.

In Ireland with the exception of northern Ireland we have the option of E10 and that's it thanks to the current Green Party leader, cycle lanes everywhere but not a decent drop of fuel. I have noticed on my 850 since E10 came in it is running warmer, I don't have a thermostat fitted so any response off the temp gauge spikes my interest and since it's been getting that (with a stabiliser and lead replacement) it's crept up a tad