Spark plug issue - any ideas?

[arpi2390]

Good day to everyone!
Here I am again with a little bit of an issue. My car had a bit of a trouble a few weeks ago with the fuel not getting to the carb, turned out to be a loose hose in the engine bay where the plastic tube enters in the engine bay and the rubber one goes on. Put everything back, the engine started up fine and ran great.
But now that we were getting temperatures of -15-20 C at night and in the day around -5 C the car wasn't really working that well. It was like it had been running on 3 cylinders so I took out the spark plugs and I noticed that it had carbon fouling on it. As you can see in the picture below:



I had another set, an old one which I cleaned up changed them over and the car was running brilliantly even in cold temps, until a few nights ago when it started to run on 3 again, losing all power, in neutral it was revs quite ok, went past 4000 rpm but in gear it wouldn't go just as last time I couldn't go over 50 km/h.
So I took out the spark plugs again and as I was expecting they were the same as the other ones that I took out before, all black and with fuel on them, they were wet.
I put them in cleaned as you can see in the picture the left one and the ones I took out were black as the right one on the picture:



Changed them again and the engine is working really nice...but I just don't know for how long.
My question is what can be causing this?
Too much fuel getting in and at low temperatures it wont vaporize as good as in above 0 C, so fuel is getting in the engine in more of a liquid form?



The engine is running nice when the plugs are clean, but I don't want to keep changing them every week
Any ideas on how to sort it out?

BTW the car is a 360 GLS with a B200K engine, everything is stock and standard.

Cheers,
Arpi

[Speedy88]

With it fouling up over a short time, I'd put my money on too much fuel getting in. Is it the same cylinder each time that stops working?

[arpi2390]

It isn't happening just in one cylinder, it's in all four of them. But not all of them were this bad, the first two cylinders were all coated with carbon the other two were a bit less black [looking from the radiator] and the first two had fuel on them too.

Thanks for your fast answer!

[volvosneverdie]

It isn't happening just in one cylinder, it's in all four of them. But not all of them were this bad, the first two cylinders were all coated with carbon the other two were a bit less black [looking from the radiator] and the first two had fuel on them too.

Thanks for your fast answer!

Mine were blacking up due to overfueling/running rich.
Adjusting the carb mixture back a bit helped and my new plugs have been fine since.

[arpi2390]

Mine were blacking up due to overfueling/running rich.
Adjusting the carb mixture back a bit helped and my new plugs have been fine since.

First of all, thanks for the anwser
I'm not really that good with engines, I'm just starting to learn things with my little Volvo and as it is a carbed engine I really don't know how to adjust the mixture, I know that the carb has some screws but I don't know where they are and how to adjust it.
If anyone could explain to me in a little detail how I could adjust the mixture. I would be really thankful.
I'm still learning about this car but I really love it only there aren't a lot of them around here in Romania so I have to seek advice everywhere I can.

Thanks again!

[Chris_C]

Yup, definately running rich to get that colour on all 4.

Arpi, have you adjusted the carburettor before? You'll need to adjust the mixture screw on it. There are a few people on here with that engine that will likely be able to help you, otherwise the "green books" in the technical section have good pictures.

[arpi2390]

Yup, definately running rich to get that colour on all 4.

Arpi, have you adjusted the carburettor before? You'll need to adjust the mixture screw on it. There are a few people on here with that engine that will likely be able to help you, otherwise the "green books" in the technical section have good pictures.

Well I have never adjusted it before but I'm off to study those "green books" than
Thanks for the answer and help! Would running rich have any of these symptoms: a lot of white smoke? high fuel consumption?

BTW I really have a fuel issue on my hand too, but I'm guessing it isn't related in anyway to this. I am loosing huge amounts of fuel, like 5-6 liters. I think I might have a leak at the tank and or either the return fuel pipe.
Fuel disappears until it reaches the last line at the fuel gauge, it just sits above it. It's either a leak or some voodoo magic

[volvosneverdie]

Well I have never adjusted it before but I'm off to study those "green books" than
Thanks for the answer and help! Would running rich have any of these symptoms: a lot of white smoke? high fuel consumption?

yes.
get someone to put the palm (face) of their hand over the exhaust and rev the engine slightly.
if theres a lot of large black specs on their hand, then thats a good indicator that its running rich. lots of whiteish smoke (other than on startup, when the choke is out) and high fuel consumption would both also be indicators.
Sounds like an easy fix with a bit of study.

that much fuel disapearing is worrying though.
is there a smell of fuel in the car?
Check the hosed under the boot floor access panel and make sure theyre not leaking.
Then i supoose, check all other fuel lines too.

[arpi2390]

Well I had a look at the green books, it has a lot of information and it is very useful I've found a lot of answers to past questions
But I can't find anything about adjusting the carburettor, just choke adjustment and engine idle speed. I can't find any other thing about the Solex Cisac carb (which turns out to be the full name of my carburettor).
So I haven't found my screws yet but I'm eager to finding them and to play with them.
The fuel leak is probably in the back somewhere near the tank only it's to cold to get under the car...I'll have to wait for the temps to get a little higher.
Thank you for pointing out the green books, theres a lot of info there I'll have to print it out a read through it.

Hope I can find those screws and thank you all for trying to help, I know I'm a bit of a beginner I'm more into computers and programming but I'm hoping taking care of engine can't be that hard to learn.

Any tips and tricks are welcome from people who have the same engine and carb

and a good day/night/evening to everyone!

Cheers,
Arpi

[Chris_C]

I know I'm a bit of a beginner I'm more into computers and programming but I'm hoping taking care of engine can't be that hard to learn.

Don't worry about being a beginner, most of us on here knew nothing when we started, and have learned from each other.

If you can't find anything (or no one has a handy picture) I'll take a photo of the page in the Haynes manual, I think that has a good exploded diagram. Worth you seeing if you can get one too, they have some good bits in them!

[volvodspec]

don't start adjusting the carb just jet,

the plugs are wet; but is this due to overfuelling? allways check the simplest things first.
it happens random, so i'd check ignition first. if you don't know when rotor, dizzy, leads are replaced; replace them just in case. big chance that this solves everything.

if not, then check up the carb; adjusting it won't fix the problem but only covers up some symptoms

[arpi2390]

Thank you all for your help, I've found the screw and I tried to set it to the best, I'm hoping that in time I will sort it and see which is the best setting, now it works really well, I think throttle response is better too and there isn't that much white smoke, just a little bit sometimes. I might still have to adjust it but I want to see if my spark plugs will get black again, I'm hoping they won't.
The engine is working great but...there always is a but isn't there? My fuel issues are getting worst and I think I've found where the leak is.
As it is still cold here today when I started it up and ran it for about 10-15 minutes setting the carb I went off to try out how the engine works and when I came back I noticed that the ground was wet where the car was sitting just about where the tank was when I was setting the carb. So out of curiosity I went over and checked out what it was...and guess what it was gas/petrol. But I thought that maybe I've been working on the car with the carb, fuel and so on maybe my hand just had fuel on it before so I leaned over and smelled the ground must have been funny to watch me but it was definitely petrol on the ground...a lot of petrol...
So I probably have a leak somewhere on the tank and I think it is on the return line just before it goes into the tank.
My question is can I get to those lines somehow from the boot? My 360 is a sedan.
I think I just have too many questions

Thank you guys again for helping me!

[kalyyyyyy]

As said before, if the carb adjustment dosen't work , then it must be the ignition. The Black substance on the spark plugs is the result of unburned fuel.Unburned fuel happens in two cases(usualy it's a combinations of the 2 factors): either the fuel mixture is to rich , or the spark is to weak to egnite the fuel properly. If the mixture is to rich, adjust the carb, if the spark is to weak there are several posibilities: bad sparkplugs(probably not because you tried 2 sets), bad sparkwires(i forgot the word- fise in romana), bad dizzycap or dizzy rotor.The wires you can check withe an ohmmeter, the dizzy cap should be clead inside without any green substance on the conectors and without any cracks-examine it thoroughly, and the rotor arm should also be clean - you can do the cleaning with sandpaper- the smother, the beter.There is another posibility, this is the worst case:the ignition computer (if you don't have the model with contact breakers), if this fails in the way that the spark isn't in the right time , than what's happening to you could be a simptom.If you have contact breakers , adjusting and cleaning them is the first thing you should do.

By the way, please post your problems on the romanian forums to , me and alf are the only ones active on the 300 section and it's lonely...

[volvosneverdie]

By the way, please post your problems on the romanian forums to , me and alf are the only ones active on the 300 section and it's lonely...

Ah dude, you sounded so lonely there.
there mustnt be a great deal of 300s in Romania then?

[kalyyyyyy]

There's a lot of them but for some reason they're hiding!