The carby on Mel's Alto was being a right bitch of a thing, so I replaced it with one I had prepared earlier. Now, even though it has been rebuilt there is a flat spot right above idle that I can't get rid of.
The little "power valve" is working and injecting a squirt of fuel when the accellerator is dabbed, but it still wants to die.
Anyone got a hint on what to check/adjust? Cheers.
It may be a dumb suggestion, but a flat spot just above idle could be a lean-out, possibly from the throttle butterfly opening before the accelerator pump or "power valve" is activated. Any way to check adjustment of it?
Brayden, I don't know what model Alto Mel has, but I had a similar problem with mine.....turned out to be a locking tab on the pilot jet ( I think that's it ) at the back of the carby......I released the tenision on this and tried again....problem solved.
Try it , if it works , good....if not, then you try something else....process of elimination.
i once had a mightyboy with the same problem... i rebuilt and changed various carbies... exactly the same problem..
it ended up being the vaccum advance on the dizzy.
lubricate the ball bearings and manually move it back and forth til the oil gets in... check that the vaccum actuator is at least half working... and then take it for a spin.
I've been messing around and rebuilt the carby to try and solve a few issues, but this flatspot persists!
Just rebuilt the distributor too, but that hasn't fixed it either.
I wouldn't be worried, but the flat spot is so bad that the car stalls unless you boot it, even that causes it to bog down badly.
Check for air leaks in your vacuum hoses , and put a timing light on it to see if the vacuum advance is working .
This sounds like a distributor issue ( bad advance curve) but these symptoms can occur if you have a bad enough vacuum leak .
I have come to the end of an era After 20 years of Kei cars It is time to move on - And almost time to leave this forum and say thanks to all who have assisted me .
Special thanks to Brayden
Nope, no vacuum leak, it is showing around -20PSI at idle, vacuum advance system shows 0 and then -12 on throttle open.
Distributor has been exchanged with one I rebuilt and problem persists.
disconect the vacume advance and bump up the timing of its conected to manifold vacume you will have good advance till you open the throttle then it retards giving you a flat spot
this may be a long shot, but one time i got alot of water in my fuel tank, and some of it got sucked into my fuel filter, and the water was sitting in the bottom half of the chamber alllwing the fuel to pass through it but when i revved it or took off in 1st the higher pressure would pull some of the water into the carby and cause it to start struggling etc,but it was fine in like second to third and just cruising,so it took me ages to work out what was going on, maybe thats what it is:P worth a try
to see if its fuel place hand over mouth of carburettor not completely just enough to make it run rich and rev it if it still flat spots its not fuel...
Other than timing issues the only thing I have had do this was a blocked Idle transfer jet - but that was on a 780cfm holley 4brl - the principles are the same but the implementation may be different.
Note the Holley was NOT on a Suzy.
I have come to the end of an era After 20 years of Kei cars It is time to move on - And almost time to leave this forum and say thanks to all who have assisted me .
Special thanks to Brayden
Now, even though it has been rebuilt there is a flat spot right above idle that I can't get rid of.
