What would you do -- rebuild carb or put in two new coils?

1983 50 HP Johnson motor:<br /><br />I put my rebuilt boat into the ocean for the first time in 4 years. On day 1, the motor would not get on a plane easily, but would sputter, plane, then 30-seconds later choke down and go into idle. It appeared to be an electical problem with the ground wire going to the power pack.<br /><br />On day 3, I fixed this wire and went out again and the boat worked GREAT all afternoon long.<br /><br />On day 6, my father-in-law took out the boat and it ran poorly (similar to day 1).<br /><br />I bought 2 carb kits (for $17 a piece) and a manual and want to rebuild them. My neighbor said that one of the coils is probably going "bad" and the carb is probably okay. I'd rather not have to rebuild the carb if they are okay. Before the gentleman who previously owned the boat died, he had the boat shop "winterize" the motor and it has sat up for 4 years.<br /><br />What would you do?<br /><br />1. Rebuild the carbs, take it out and see how she runs?<br /><br />2. Buy two new coils ($30 a piece), replace them, and take it out? If she runs good, return the unopened carb kits?<br /><br />3. Buy two new coils and rebuild the carb anyhow?<br /><br />Do I need to replace the fuel lines as a good measure as well?<br /><br />The motor idles well, will get up on a plane and run good for a while, the bulb on the fuel line stays firm (I don't think there is a fuel leak), and it cranks easily.<br /><br />Here's my first post here and a little more detail: Initial diagnosis from this board

Re: What would you do -- rebuild carb or put in two new coils?

Typically, if the coils are going bad, they will be cracked and arcing to the cylinder head. You should be able to see the arcing and hear the "snap" of the spark as it arcs. <br /><br />If the motor has sat for four years, the carbs are likely to need a cleaning (at least) and possibly a complete rebuild. They're not as complicated as they look, but a manual does come in handy. The intermittent good running could mean you have a floater in one or both carbs...<br /><br />- Scott

Re: What would you do -- rebuild carb or put in two new coils?

While I would be the first to agree that a motor that has sat for 4 years may need a carb rebuild just on principle I don't think your problem is the carb. From your description it sounds to me more like you are dropping a cylinder from an ignition problem. Your early fix with the ground wire on the power pak suggests this. Don't replace anything or rebuild the carbs until you find the malfunctioning part and you will avoid unneccessary expense. Too many people think throwing parts at an engine is the best way to fix it. Get a manual and start doing diagnostic tests on the ignition components.<br /><br />Start with the connections and check that wire you said was loose. If it was loose the wire may also have a break in it elsewhere. Get a continuity tester (checks for broken connections) and a multitester (volts, amps, and ohms) and do the tests specified in the manual.<br /><br />Your on again off again motor performance sounds like a wire that is on again (connected) off again (disconnected).