Merkava_4 wrote:I think I may have found the problem. With the carburetor mounted to the tank without a gasket and the screws tightened, I can slide a .006'' feeler gauge in between the mating surfaces on the side that faces the intake manifold tube. With the gasket installed, and the screws tightened, I can slide a .0025'' feeler gauge in between the mating surfaces on that same side. That's the side opposite of the primer bulb. The other three sides aren't quite as bad. The primer bulb side is almost completely flat still. I first started out with a .002'' feeler gauge which is what Briggs & Stratton recommends for checking warpage. After that I tried a .004'' and then onto the .006''. Even though there is no gasket there, I'm pretty sure you're not supposed to be able to slide a .006'' feeler gauge in there. Being that the pickup tube and the emulsion tube tower is in the way, I don't think I will be able to file the surfaces flat.
Yeah that is pretty bad. I had not realized (Silly Me- read your original post too fast and missed the part about carb on top of tank!) that carb was on tank - with those it'd be fairly common to find warpage , though not quite so severe. Many of them can be fixed by doubling up the gasket - and the warpage is often caused by dumbass techs that think they know what "8 to 10 inch pounds" feels like by hand. They'd be wrong. all too often they just give it a "good twist" but then they've severely over-torqued the screws which deforms the nylon body and causes warpage - same reason the air cleaner bases warp causing primer failure on the float carb equipped mowers, and many other areas where nylon or plastic body stuff is screwed down to metal.
So, first try double gaskets and if that don't work, you may have to go on amazon and find a replacement (Might even find an OEM one for under 30 bucks someone liquidating a NOS inventory, etc.) Briggs also had a "gas tank repair kit" involving a tiny roll pin and a .003" thick tiny nylon washer that fit around it to resolve the warpage issues on the older metal body carbs, but they've never worked for me on the pulsa-prime.. but double gaskets has often helped (One new with new diaphragm and one old one, in a pinch, but I rather doubt it'd do for .006 warpage, so you may need 2 gasket diaphragm kits and throw out one of the diaphragms) - The idea being that as you tighten down the screws the "high points" of the surface will sink into the compressible gasket material while the "low points" can make contact with, but not fully compress, the gasket, but that'd seal 'er up.
Oh yeah if you wanna be more accurate in your work, get yourself a nice accurate torque screwdriver that does 0 to 50 inch pounds or so, take care of it (reset it back to lowest setting when done, but not beyond, before putting it away, keep it clean and in a good storage case where it isn't gonna get banged around) - A decent one isn't all that expensive, and if you do this kinda work for money, it increases the quality of your work, making you worth more, and reducing comebacks, and thus pays for itself.
