Is this normal? (Primer use creates fuel stain)

[170C]

One other tip, you might pull your primer out again and check the "O" rings to be sure they are seated properly. Although not likely, but the new "O" rings might have been the incorrect ones? I changed mine a year or so ago when I started getting fuel on the primer plunger when I pulled it. Replaced the two "O" rings with new ones from an "O" ring assortment from Harbor Freight Aircraft Supply and have had no problems since

[pmel22]

This ended up being a failure of the primer. Even though the primer was closed and locked, a small amount of fuel would still move through the primer. Replaced the primer and all is well!

[pdb]

Nope nothing has changed in the 3 years I have had the plane. Just recently noticed a harder to push primer.

1) Have you used any car gas with ethanol?
2) Did you use the correct o-rings?

There is a thread below that correctly cautions about both. Improper o-rings may fit and function perfectly initially but swell or deteriorate, especially if exposed to ethanol. Take a look here:

http://www.cessna170.org/forums/viewtop ... ton#p75206

[pmel22]

We replaced the o rings with the correct ones, and never used mogas. If you look down the primer the seat had a small internal crack, I know sounds crazy but that was it.... I was getting a blue stain on and off in the cowl, and the plane was running rich, all is better now.

[canav8]

We replaced the o rings with the correct ones, and never used mogas. If you look down the primer the seat had a small internal crack, I know sounds crazy but that was it.... I was getting a blue stain on and off in the cowl, and the plane was running rich, all is better now.

Your lucky it was running.