Quote Originally Posted by Patrol'n View Post
Thanks mudnut, hadn't thought of the fuel pump or solenoid, the throttle response and power aren't a worry, it holds highway speed and accelerates pretty well for such a heavy vehicle. Regards the fuel pump, it's electric and in tank isn't it?

Maybe I'm tired but how would the pump slowly failing cause poor economy? Not doubting, just curious, and how would I test the pump?

I may have to find a dyno tuner in Perth that can work on Carbied motors, anyone know a good one?
Check the float level of the carby from the slight glass while idling and revving. There is no easy way to check the float level while taking off unless
you setup one of those el cheapo inspection camera. But I reckon idling & revving test for the float level is good enough in many cases.

I would've thought a low fuel pressure would cause lean running issue by making the float too low, and the high fuel pressure vice versa.

What you can do is to take the first spark plug out and check it for soot build up, clean it and put it back and drive for few minutes and check the
spark plug again. If it's building up soot in no time then you know you have a carby rich running issue, which easily translates into a fuel economy issue.

Another thing you need to make sure is the auto choke. Check to see whether the auto choke open up completely after few minutes or warming up. You need to remove the air cleaner to see of course. If the choke is not opening up then the continuous rich running will mean poor fuel economy.

3km/L is pretty crappy fuel economy for sure. You have to find the culprit and fix it, 'cos it's not just about the fuel economy. It is saying there's something else is wrong with the engine for that poor economy, so it's a good idea to find out before taking off for any long treks.

Compression test also might be a good idea to find out whether the head gasket is on it's way, 'cos that can affect the fuel economy as well.