fearofweapons Posted July 22, 2018 Share Posted July 22, 2018 So you may have seen my previous posts about the trouble I'm having with my 2.5 petrol transplant into SIII. We have; changed the carb for a new one, changed the in line fuel filter, checked the fuel pump, changed the HT leads, changed the coil and condenser and points, checked the spark plugs, checked for vacuum leaks, checked the spark AND it still fails. Symptoms are it will start and run you can rev or leave ticking over but within a couple of mins it just dies away as if the power were cut; regardless if hot or cold. We have run without airfilter on - still fails. We have watched into the carb and fuel is still flowing - the in line filter is still full after it dies. We are stumped. At this point just about any suggestion will be welcomed. We are supposed to be going away next w/e and that is in doubt now 🙁 cheers Richard Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted July 22, 2018 Share Posted July 22, 2018 Tried running it from a separate fuel can? Quote Link to comment Share on other sites More sharing options...
Bigj66 Posted July 22, 2018 Share Posted July 22, 2018 I was always taught a rule of thumb that if an engine ‘cuts out’ it’s usually an ignition problem but if it starts to fail and then gradually dies then it’s fuel related. It is just a rule of thumb though. From what you describe it’s sounding like an ignition/electrical problem. After it cuts out can you restart it again immediately and how does the starter motor sound when you crank it over? It could be good to at least eliminate a battery drain/ poor earth as part of the problem as you seem to have checked all the basic possibilities. Have you taken any electrical readings during the fault tracing to date? Was the fuel solenoid replaced with the carb? Quote Link to comment Share on other sites More sharing options...
fearofweapons Posted July 22, 2018 Author Share Posted July 22, 2018 Gents thanks for the replies. Not tried a separate fuel can but we are not seeing any contamination evidence and flow remains good. Readings - voltage into the coil remains good. We have even linked +ve battery direct to coil input. Not checked earthing though so will add to the list. The new card came with new solenoids and I hear them click open with power applied and fuel flow into carb seems good from observation with out air inlet on. Quote Link to comment Share on other sites More sharing options...
lo-fi Posted July 22, 2018 Share Posted July 22, 2018 When it dies, does it suddenly cut out, or are there some symptoms heading up to that? Does the exhaust note change, surge or hunt etc? Given all the stuff you've changed, I'd say maybe an air leak that gets worse as something heats up. Have you put a timing light on it and left running to check it's still sparking when it dies too? Quote Link to comment Share on other sites More sharing options...
Gazzar Posted July 22, 2018 Share Posted July 22, 2018 I'd be looking at the intake manifold, an aerosol can of WD40 could be useful - spray as it dies, if it recovers, you've found the leak. Quote Link to comment Share on other sites More sharing options...
fearofweapons Posted July 22, 2018 Author Share Posted July 22, 2018 Timing light - yes we have had one on and it sparks all the way through. Also had a false plug on and could watch the spark - although we could hear it seeming to vary in strength a bit but no much. Hunting - not really. I sometimes think it feels a bit lumpy in the lead up but not strongly and no other changes discernable. Quote Link to comment Share on other sites More sharing options...
fearofweapons Posted July 22, 2018 Author Share Posted July 22, 2018 2 minutes ago, Gazzar said: I'd be looking at the intake manifold, an aerosol can of WD40 could be useful - spray as it dies, if it recovers, you've found the leak. Thanks we'll give that a go. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted July 22, 2018 Share Posted July 22, 2018 Carb cleaner or brake clean is much less messy. Quote Link to comment Share on other sites More sharing options...
fearofweapons Posted July 23, 2018 Author Share Posted July 23, 2018 So no sucking around intake manifold. Will work through earths. Also going to check that non of the components put on are faulty. When restarting after a failure sometimes it will just start right back up - other times it takes a bit of cranking. But it cranks strongly. Quote Link to comment Share on other sites More sharing options...
Gazzar Posted July 23, 2018 Share Posted July 23, 2018 Then I'd look at the coil. Quote Link to comment Share on other sites More sharing options...
jordan_meakin Posted July 24, 2018 Share Posted July 24, 2018 Does it have a brake servo? Quote Link to comment Share on other sites More sharing options...
fearofweapons Posted July 24, 2018 Author Share Posted July 24, 2018 So that particular problem is now solved. Many thanks for everyone's input. Turns out a small bud from a tree, previous owner as we don't have any of those trees, was wedged up the fuel intake pipe in the tank. It allowed enough fuel past for it to run on tick over but slowly starved it of fuel when under load. You live and learn. Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted July 24, 2018 Share Posted July 24, 2018 That's brilliant, glad you got it sorted! Quote Link to comment Share on other sites More sharing options...
Gazzar Posted July 25, 2018 Share Posted July 25, 2018 That's unusual. Trees usually only grow in the window channel, so yours must have been a special edition. 1 Quote Link to comment Share on other sites More sharing options...
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