Good evening! I’m having an engine issue which I cannot seem to solve - any help would be greatly appreciated! About engine: - 1.6 engine - Solex 34pict3 - Electronic ignition What’s going wrong: Engine is running really rough (quite hard to start - I believe this is due to spark plugs getting very black & chalky, as if I remove them and clean, it starts up first time (pic here of black plugs - likely running rich??) . It quickly goes back to running terribly (likely due to dirty spark plugs after starting) Carb Bypass and Volume Screw do not seem to affect anything (turning them in/out doesn’t really affect RPM). The volume screw in particular does seem to turn quite easily (as in, you hardly need to add effort to turn it). Possibly affecting mixture + ultimately causing black spark plugs?? One spark plug hole was fitted with a time cert by a company when I dropped the engine and removed heads. However, it is now stuck to the spark plug. I can remove the plug and reinstall using the groves made for the timecert (it feels as secure as fitting a spark plug normally). I want to fix this with high temp JB weld + bonding to the head asap so it’s not pulling out with the spark plug, but possibly could affect the engine running?? What I’ve done: Checked for air leaks Cleaned the carb completely + fit new seals Switched plugs around + new HT leads New distributor, new electric ignition All hoses securely fitted Checked spark on all plugs + all good (when clean) Checked valve gaps Here’s a video of the engine running: https://streamable.com/ua54b4
It possibly could be timing? I could attempt to reset it again once running with the strobe light, but ideally I need it to run a bit better before doing this? The spark plugs get blackened so quickly it runs quite rough quite quickly!
Here's the off-the-wall but possible answer - your heads want long reach plugs. As I learned today, Mexican heads need different longer plugs and I did once come across a van where short ones had been fitted - it did run, the owner drove it to my workshop. It went much better when the spark wasn't happening halfway up the hole. If you think it might be this, get a straightened out paper clip, or even a thin screwdriver - poke it down plug hole and press against the threads while withdrawing - near enough will do - it's either about 12 threads or 18-ish. If it does want longer plugs, rather that just wanging them in, get a plug thread chaser to clean the threads as they will be full of carbon. Just from the distributor position, you might be right, the can is usually more aligned with the engine. Try turning it a bit anti-clockwise and see if it runs better, but don't drive without setting it properly.
Doesn't sound too bad to me, I'd check the plug thing and remember - just because someone fitted a short insert doesn't mean they got it right. I'd also (probably first thing to do along with the timing) replace the o-rings on your adjusting screws AND/OR set the throttle stop correctly so the screws can work. If the stop holds the throttle plate too far open the screws don't work. The correct setting for the throttle stop with choke off is a fag paper gap. Valve clearances, then timing, then carb fiddling is the order to do things.
