Save me money please.

[bob654]

Hi, I have been trying to track down a cylinder not firing problem.

I would like to run a check list by you guy, please.

I have swapped coils. No difference.

I have swapped plugs, no difference.

Swapped leads, no difference.

I have good compression.

Pulling off the  vacuum pipe. makes it change cylinder.

I put new o-rings on inlet rubbers, so they are tight. Exhaust is good.

So before I bolt on the new carbs, and then cant return them if the problem persists, cos, " he cant sell used as new" ( fair enough),  which arrive tomorrow, with rubbers and pods, can you tell me, if you all agree,

it's carbs?

Although the idea of new carbs is appealing, the thought of having spent the cash and still having the problem!  Is sickening, honestly.

Edited June 17, 2020 by bob654

[Gixer1460]

If you do have big fat blue sparks then although timing may be incorrect, you can pretty much rule out electrics (not deffo though) and carbs are a likely candidate for being the problem. Swapping cylinders is the weirdest bit !

[bob654]

My guess.Is 3 is flooding cos the fuel air screw is broken and so, not firing. When the vacuum is removed it allows a different mix and fires, then upsetting the mix for 4. Leaving it impossible to set / balance.

[Blubber]

Pinched diaphragm in the current carb set?

[bob654]

No diaphragm, on these. Thanks.

[bob654]

New inlet rubbers, and all is good, thank you.

Twits are almost indistinguishable from the populace.

[Askamaskinservice]

18 hours ago, bob654 said:

Twits are almost indistinguishable from the populace.

Sorry if i'm beeing a bit thick here i don't understand the lingo???

[bob654]

I thought I was less stupid than I turned out to be, who knew.

And thanks again to GS7_11 for his help.

[BigT]

Pull the vacuum line from the fuel tap and plug it with a 6 mm bolt, or similar

Run the fuel tap on prime

See if the cylinder starts firing

 

[bob654]

New inlet rubbers, and all is good, thank you