iv just changed the carb of the van as the one that was in the back of the van wasn't working properley (thats were it was when I bought it ) Iv used the one of the doner that was chucked in the back, they are the same make but the knackered carb was a zinith 36 IV and the one that is now fitted is a 34 IV what is the diffence becuase I cant tell? .it ticks over lovely but struggles when driving oh and I think the thermostat is stuck closed is there any way of freeing it of with out taking it out