Hey folks, Landy series 3 2 3/4 petrol. Runs well and have no issues whatsoever with it driving etc.

My question is the spark plugs. I do use lead replacement additive but to be honest after replacing the head gasket the valves looked really good so will not bother in future.

However, I’ve noticed the plugs have a white substance on them like limescale. It runs well (slightly rich). It maybe nothing and I’ll leave alone but would rather ask ‘just in case’.

Thank you

Rich

You may think that your engine is running rich but white deposits are the result of running lean.
If it were running rich they would have black deposits on the plugs.
A nice light brown is what there should be on the electrodes.
A Gunson colortune is a simple to use tool to set up older carb fed engines.

Thanks Tottot that’s what I’m thinking. Defo looks l like it’s running lean.

Going to turn the mixture up slightly to helpfully get the plugs a nice brown for now

Gun7354 said:

Thanks Tottot that’s what I’m thinking. Defo looks l like it’s running lean.

Going to turn the mixture up slightly to helpfully get the plugs a nice brown for now

Click to expand...

Used to be 1 & 1/2 turns for standard running

Going to start from basic - thank you

thats only really for the idle tune the screw if its running lean it means the main jet has an obstruction or something else, but as i said the mixture screw is only for the idle. the main running jet is fixed and cant be adjusted but changed out for a large one. you could have a issue elsewhere but maybe try to replace the plugs first and you can do the idle mixture and then leave it a few weeks and then recheck hopefully its the idle mixture thats the issue. if its still a issue try stripping and cleaning the carb and then give that a try, i think she will run hotter if its lean and will be slightly down on power but might not be noticeable.

what make of plugs are those i see just visible made in france..? i got BP5ES NGK plugs in my 2a they are cheap thai junk now they used to be japanese made but they went the poor route or the auto place sells the cheaper NGK plugs im sure they still make them in Japan, i had the same with denso plugs i tried they was made in China.