1988 520h

[Johnm1226 0]

I have a 520h that after 15 minutes of cutting grass revs very high and noticed also that the vacuume gauge jumps up and down. It does not hold steady? Anyone know what the problem could be? Seems to run fine when cold.

[CRE1992 135]

Sir you probably have a dirty carb as the culprit. Try adding some choke, if the engine smooths out take your carb off and soak it.

[Sparky-(Admin) 19,756]

I've only owned one 520 and the vacuum gage was the jumpiest thing ever.....totally unreadable.

Mike............

[tiggercl 28]

I've only owned one 520 and the vacuum gage was the jumpiest thing ever.....totally unreadable.

Mike............

I experienced the same 'pulsing' when I replaced a vacuum gauge on a 520H. The solution was to add or squash more padding (or felt?) on the input side of the gauge where pipe connects. I recall just adding the packing from the old vacuum gauge into the new one essentially doubling up .... settled it down beautifully...

Paul

[Johnm1226 0]

Thanks for your advise. I soaked the carb for 1 week and put it back together...same issue. I discovered that the problem turned out to be the gaskets to the Air Intake were in bad need of replacement. Evidentally i think too much air was being sucked in causing it to run like crap. I replaced the gaskets and it runs like a brand new machine.