So I took the Zodiac out for a third time...
I changed the fuel line to a genuine Quicksilver quick connect style line, and replaced the EPA cap on my Attwood tank with a Moeller venting cap (which fit just fine). It was the pre-assembled 8' line with the standard 1/4" thread on one end, and quick connect engine fitting on the other. Had a full tank, and verified that the engine side connector was snapped in place, but the primer bulb just wasn't firming up. Even the crappy Attwood line I had before would firm up pretty quickly after a few squeezes, but this one just wasn't having it. The engine managed to start when i hit the electric starter, though. After leaving the dock and meandering through the no-wake zone to head out, the engine was "sneezing", and continued to do so at times when we were running at less than 1/3 to 1/2 throttle. Could this be caused by a bad bulb????
I also noticed a slight squeal coming from the engine when bringing it down from full throttle that'd last a couple seconds.
The engine should be okay mechanically, I've had it inspected by multiple reputable shops. The only thing that's been done to it recently is the installation of a Permatim hydrofoil (since the inflatable I have it on wasn't planing), and me installing a lower pitch (7 pitch) prop from the stock 9 to bring the RPM's up a little. I sprayed everything with Corrosion X oil, including the thrust washer, spines, prop, shaft spines, and nuts before putting everything on and cranking the prop nut down. I should also note that I'm now using a 1-1/4" white oak shim to get the lower unit up higher.
Any thoughts??? Though the boat seems to be planing just fine now (thank the lord).
EDIT: Just tried squeezing the bulb with the line connected to the tank but not the engine, and it firmed up... Weird....