543 b ---finally found the problem !!!

[buddy]

MY 543-B Would start and run fine for @ 1 hr then die slowly like fuel starvation. wait @ 10 minutes and would re start and run for around 5 min. and die out again. tried everything on all the posts and still no answer ! I finally got pissed and figured pull the tank and see if it is full of gunk. While removeing the tank I found the fuel supply line had been cut a little to short from the factory @ 20 yrs ago and was being pinched in between the rear of the tank and the body of the machine. (the lower left corner) it is supposed to be long enough to fit inside the detant moulded into the back of the plastic tank along side the return line. The line was about 2 inches too short. Figured i'd post these results as I did not see this result posted. Replaced line with correct length made sure it ran behind tank in the correct area and she purrs like new ! and ran great all day. Mark

 

[Tazza]

Glad you found it, yet i know it must have been frustrating trying to find the issue.
Generally the fuel primer bulb sucks flat when there is a restriction before it, but with age they do go hard and they don't flatten as easily.