tackdriver56

Oh! Thanks for the balloon test info. Something else I found that I can warn about, is that when I removed the induction section to check the crankshaft seal, I had to make a new gasket for the induction section. It was marginally thicker than the original. Whether from the increased thickness, or lack of resilience of the old O-ring, I needed to add TWO layers of the same gasket material between the o-ring and the induction hole, to seal around the bolt.

Just to be complete, the priming assembly did need to come off for proper cleaning. It's not obvious in the photos, but the passage out of the diaphragm/priming chamber is funnel shaped, with a tiny hole at the bottom. Mine had been partially blocked by some debris, which became obvious when I removed that assembly. There was also debris in the filter screen, in the carb body, below that "funnel". So it's well worth the effort to disassemble and clean thoroughly. Thanks again for the advice.

My PPP is now running, thanks to helpful advice from Wallfish. After changing the diaphragm, I still needed to disassemble the carb and clean the screen adjacent to the needle seat. One other major problem was an opening directly from the gear-case into the induction section, caused by a previous owner failing to install one of the screws. The shaft seal looked a little worn but it's serviceable. Gear oil now stays in the gear case, where it belongs! I moved SNOW today!

Success! Aside from finding and installing a compatible screw to replace the one missing from the gear-case through the induction stage, I also cleaned debris found in the fuel passage from the diaphragm to the filter screen. Gear oil stays in the gear case, and the engine runs! The PPP cleared a lovely patch of snow today! Thanks Wallfish, for your helpful advice!

Seems like somebody worked on this before, and had parts leftover At least the case o-ring was still in place. I guess the only reason it ran for me the first time, was the heavy oil I filled the gear case with ;-) At least the 8-32 x 1.25 screw & lock-washer should be easy to find. I did get the induction side crank seal out. The shaft diameter is 0.36",and the seal OD is about 0.49". The seal cross section is approximately 1/16" square (u-shape).

Question: Is there supposed to be a long screw/bolt from the large gear-case shell, crossing THRU both sides of the carburetor mount, threading into the side of the crankcase? It sure looks like those empty holes could be an air leak to the gear case.

Thanks, I hadn't thought of that! Hope webhead does repost the balloon test...

It looks good... I'm going to take it apart soon. Thank you!

Does anyone know the specifications or exact measurements for the crankshaft U-seals? Also, any advice on how to safely remove the centrifugal clutch from the crankshaft, before I try a generic puller? (This is internal to the Polaris Power Pole gearbox, similar but not identical to your winch?)

Okay, pressurizing the "oil fill port" on the PPP gearbox to 25 psi, I got unimpeded air flow through what should be a crank seal. I also got air flow OUT of the carburetor, which shouldn't happen if there's a functioning reed valve. So at least two problems to solve before my next test run. The flywheel side crank seal was NOT leaking, but if I'm going to do a complete tear-down, I might as well cover all the bases. Recommendations for seals? Anyone?

Thanks guys. The manual priming works well., and I did perform the flow/no-flow checkball test with clean fuel line. (also blew carb cleaner through it, without the diaphragm installed).

I've cleaned it, and pulled the cylinder, which looks good. The piston shows a little skirt scuff, but the rings look good.. Planning to pressurize the gearbox slightly to check the seal on that side, since it aspirated the gear-oil. Anticipating a tear-down. Anyone have seals and gaskets for sale?

Thanks John. I guess I'm going to get a detailed education, as I take this thing apart... I've worked on the little COX model engines, which used sort of a reed valve, and a 1960's Bridgestone motorcycle with a rotating disc intake valve. I'm still trying to wrap my head around how the diaphragm works in these engines. I guess the crankcase vacuum draws the fuel out into the intake air, and when the piston is on the "down stroke" the reed prevents backflow to the carb, the charge is transferred to the combustion chamber, and the spring/lever under the diaphragm pushes it up, drawing the next shot of fuel from the tank into the carburetor. There was talk in the Walbro docs of there being a separate air passage from the crankcase to the diaphragm chamber,.. to give it a boost?ext Anyway, my next step is to remove the carb from the engine, which I haven't yet done, and make sure the passages to & from the needle are open.

Here's a link to today's testing: http://youtu.be/vEBSLmRamE8