2a 2.25 petrol compression/blue smoke question

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joe_m

Active Member
Posts
100
Location
Yorkshire
Hello there. Any help appreciated!

‘62 2a, 2.25 petrol.

I have just acquired it, the previous owner told me he thought it had a low compression issue. It has a misfire.

Yesterday I thought I’d take a look at it. I went to it cold, having not had it running for a good few days. Took all the plugs out to find them wet in fuel. So I dried and cleaned them. Put them back in and checked compression. Taking one plug out at a time. They all read at 134psi (or there abouts). Not too bad I thought? Concidering that was stone cold too! Put all the leads back on and started her up..ran well without misfire. But smokey. At this point I wondered if it was just running far too rich? Hence wet plugs? Tried to lean it off but with the mixture adjustment screw wound right in it was still seamingly rich..blue/white smoke but smelt like fuel rather than oil. After running a little while the misfire came back. Plugs wet again.

Any ideas?

Thanks

Joe
 
Blue smoke is usually oil, but as your vehicle is 50 odd years old, your carb (Solex?) is probably in need of a service. Or has it just not been used for a while? Often a 'good run' helps blow the cobwebs away. How's your ignition system? Points correctly set? Decent pug leads and correctly gapped plugs? Dizzy cap condition. When was the oil last changed? All cheap and easy to check/replace. Let us know how you get on.
 
Carb is a zenith. I’ve ordered a service kit. I wondered if the volume screw might be buggered. Looks a little scored and bent. Not bad at all..but could be it?

Ignition system is good. It’s all been replaced recently. Oil change, I’m not sure! I don’t know when that was last done.

I’m about to strip it down to put on a galved chassis..but I thought it would be a good idea to know it would run well before I took it to bits!
 
Hello there. Any help appreciated!

‘62 2a, 2.25 petrol.

I have just acquired it, the previous owner told me he thought it had a low compression issue. It has a misfire.

Yesterday I thought I’d take a look at it. I went to it cold, having not had it running for a good few days. Took all the plugs out to find them wet in fuel. So I dried and cleaned them. Put them back in and checked compression. Taking one plug out at a time. They all read at 134psi (or there abouts). Not too bad I thought? Concidering that was stone cold too! Put all the leads back on and started her up..ran well without misfire. But smokey. At this point I wondered if it was just running far too rich? Hence wet plugs? Tried to lean it off but with the mixture adjustment screw wound right in it was still seamingly rich..blue/white smoke but smelt like fuel rather than oil. After running a little while the misfire came back. Plugs wet again.

Any ideas?

Thanks

Joe
Carb is a zenith. I’ve ordered a service kit. I wondered if the volume screw might be buggered. Looks a little scored and bent. Not bad at all..but could be it?

Ignition system is good. It’s all been replaced recently. Oil change, I’m not sure! I don’t know when that was last done.

I’m about to strip it down to put on a galved chassis..but I thought it would be a good idea to know it would run well before I took it to bits!

Like he says, good service and tune up is about all that those usually need. I wouldn't worry too much about compression, most engines that age will be a bit worn.
Try setting the tappets, changing the oil, and continuing with the carb overhaul.
And use mineral multigrade oil. It is possible your smoke issue is caused because someone has used synthetic oil, which may glaze the bores, and possibly bypass the rings, because it tends to be very thin.
 

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Thanks chaps! Like I said, it’s going on a glav chassis as this one is rotten. And it’s got a bit of unececery filler here and there too. As for the wing mirrors...I don’t know what they were thinking!?!
 
IIRC some Zenith carbs had a problem with the body warping and giving rich running symptoms. The answer was to rub it flat but I can't remember exactly how, someone on here may remember. Might be worth looking into/doing while you have it off and apart.
 
Blue smoke is oil burning. Valve seals may have gone hard.As Turboman say's use a good mineral oil.Check spark plugs are the correct one's.Do not worry if smoke is just at start up and then clears.Gunson Colour tune is a good tuning aid for petrol engines.
 
Interested in how your carb overhaul goes, keep us updated. Oh, and we like pictures :D

Success, ish! I rebuilt the carb, lapped both halves of the body. I found the accelerator pump stuck in its bore. Someone had had a pair of pliers around it before hand! Anyway, I got it out and freed it off somewhat and it ran lovely! No smoke or anything. Then it started to smoke again. Checked the accelerator pump..it was stuck again! The spring on it was damaged..thus fouling the bore. So I have ordered a new one!
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