If its a fuel feed issue you will have to check using a jamjar to catch the fuel being pumped , pull a fuel feed off a carb. while you crank with the coil negative wire disconnected avoiding sparks. Then I would clean out both idle jets- look through them you may find one is visibly blocked if you hold them up to a light. Also pop the rocker covers check the rocker arm assemblies are all bolted on. You end up with a useless engine that will run but only about 10mph if one side is loose.. Same losing two cylinders for whatever reason..
Sorry wasn't ignoring your post, it's an older malpassi with the metal filter cover so I can't actually see the filter I will still take it off and have a look though
I didn't want to push the issue, I know you're under a load of stress and I wasn't sure that I'd be helping at all.
Just checked the rhs carb and the idle jet is clear, I can't seem to remove the lhs as it fouls on the firewall, I only have a 13mm spanner and pliers with me and a socket to change the spark plug and fan belt, I will see if I can beg one tomorrow
I've taken out the malpassi fuel filter as I also had a plastic one inline which looked cleaner , still no difference The engine was run for maybe 3mins and is now to hot to check the valve clearances so I will check in the morning, I did take the rocker cover off no 1&2 and no movement in the rocker arm so can't put a feeler in to check I presume where it has got hot in that 3 mins of driving at 4mph
For reference if the engine is less than 50 deg C you can check rocker clearances. Easiest to wait though. So so far adjusting the points has changed things and that is all ? So changing fuel filters changed nothing. Next though is check for fuel flow from the pump, also if its mechanical check to see if the pivot pin is still there.. a tank blockage can sometimes be cleared by extending the pump inlet fuel line up above the tank fuel level with some hose and blowing either with a mouth or gently with a tyre pump, without breathing or swallowing fuel..
Valve clearances - doubt it, it would be lumpy idle. Fuel starvation - no - there's 2 x carb float chambers full and it idles.. It would take a few minutes driving before the carbs were empty, not merely getting up to 5mph. Blocked idle jets - no, it idles. Sounds like a weak spark thing to me - coil, condenser, cracked distributor cap?
Cheers zed, how do I confirm weak spark, I'm in the arse end of nowhere, if I purchased all 3 would it probably cure the issue ?
Hmmm, well, I would hope so, but we only have your descriptions and what you've checked to go on. Can't be right every time, just saying it sounds like a weak spark and those are known causes that can effect every and/or random spark (rather than just one cylinder like a bad plug or lead) and show up under load. Coil is normally worse at higher revs but at least those parts are cheap and it doesn't hurt to have spares. Apologies in advance if that doesn't cure your problem.
No apologies needed, I'm happy to throw parts at it at this point the alternative is not wort thinking about at this point, I may have access to a 009 distributor would that be worth a try? Would eliminate the condenser as they are different to the svda I believe?
This however (I think of it as 250F) is bliddy hot though, I'd have slowed down, pulled over at 240F and wouldn't have been happy driving it much above 220F I know and love the fact that my type-4 never gets over 95C (into the engine, the sump oil is no doubt warmer). So, though I don't like to be a doom monger, I hope you haven't damaged the heads.
