We have a 1984 Invader that was donated to our Boy Scout troop. The motor was rebuilt last year and ran great for a few outings. Last time out, it started up ok, but ran very rough at idle. In gear at full throttle seemed to work fine. However after 15 minutes it misfired when let off the throttle. Continued to get worse and would misfire and stall when in gear. Had to limp back to the dock at a very slow speed, otherwise would cut out and stall. Took it home, replaced the fuel filter, added gas conditioner, and checked plugs (greyish/white seem ok). Took it back the to lake and same thing. Idles rough, misfires a bit and runs at first and then shuts down after 15-20 minutes. Anything else we should check before we haul it back to the shop?
