Re: 1976 Johnson dies when put into gear..Please help!!!
You have great compression on that engine. Worth putting some $ into. Your mechanic is correct-this carb has fixed idle and main jets. The idle speed/rpm's is set by adjusting the idle timing of the engine, not the carbs. It is common to have idle problems if the idle rpm's are set too low. Check this issue first. The idle timing needs to be adjusted only when the boat is floating in the lake, and is in forward gear. You can't set it on the trailer. Set the in-gear idle to between 650 and 750 rpm's. At that rpm, the engine should idle/shift normally. If you still have problems, it could be a carb/fuel issue. When that engine idles, the butterflys on the carbs close all the way. A little air flows through the small holes in the butterfly plates. The fuel at idle passes through special dedicated idle passages in the upper carb bodys. It is not unusual for fuel to evaporate in those passages over long storage periods, such as over the winter. When this fuel dries up, the gelatin can clog these small idle passages, causing idle issues. (It is typical/normal that when you crack the throttle slightly, that the engine will run better. Once the butterflys are cracked open (even slightly) they will draw fuel from the huge main jets, permitting the engine to run nearly normally throughout the rest of the rpm range.) When this happens, a carb rebuilder can't visually see the dried fuel and your mechanic may may have not addressed this potential problem. It is possible this is what has happened. When rebuilding carbs, you need to use some product which will dissolve dried fuel, such as a Gumout type product. An aerosol version of Gumout works well. When disassembled, you spray this through a fuel passage on one carb, noting the exiting flow rate/volume. Then blow through the same passage on the other carb, noting it's exit flow. You want to make sure the exit flow is the same from both carbs on that same passage. The repeat on the next passage, etc.
