JamesCoste
Chief Petty Officer
- Joined
- Jun 15, 2003
- Messages
- 595
50 HP Johnson, Model # J50BELCTA, Serial # J5810665<br /><br />Can I determine the year of this motor? It is the original on the boat (an '83) so I'm guessing that it is in that range. Does Johnson build a new 50 HP motor every year or do they stick with the design for a few?<br /><br />First a bit of history (brief):<br />I just finished rebuilding a 1983 Glastron boat and took the boat for its first drive. The motor sat for 4 years until it was sold to me. I changed the plugs, hooked up the gas tank and battery and water hose adapter and it cranked right up. While I worked on the boat, I would occasionally crank it so it could run a little.<br /><br />The first time I took it out, it cranked right up, but wouldn't run full-throttle easily. I would give it full throttle and it would go maybe 1/4 speed of what I would expect. Suddenly it would take off and run fine for a bit before slowing down on its own (throttle still full). I would shut down the motor and crank it up and the same thing would happen (crank, run slow while at full throttle, then fast (for maybe 45 seconds) then slow down to a crawl at full throttle). Eventually, it refused to crank completely and we were stranded out in the Gulf of Mexico (near shore at least).<br /><br />When I got home I took the cover off and found that a ground wire to the ignition (?) was really loose. I wiggled it and it broke loose. I fixed the wire, sprayed carb cleaner on the outside of the carb (let it sit for 30 minutes then sprayed it while it was running), cleaned the plugs (which needed it, the fuel filter (which was very clean). It cranked up easily once I fixed the wire. My neighbor who is a pretty fine shade-tree mechanic explained to me how that without this ground wire, that piece of the motor (I believe it was the ignition?) would not know what to do with the throttle.<br /><br />Good news! 
I took it to a freshwater river (upriver -- I'm learning) and it ran beautifully. It was very responsive and would jump up on a plane instantly and run wonderfully without leaving hardly a wake. I ran the motor up and down the river for nearly two hours at various speeds. The motor appeared to be completely fine and "fixed".<br /><br />Bad news! My father-in-law (retired) took the boat back out to the flats while I was at work and he said it acted just as it did when we first took it out but it never got on a plane and ran full out.<br /><br />1. First of all, I'd like to know how the boat runs great one day (for hours) and then 4 days later, acts "sick"? <br /><br />2. My guess is that I need to rebuild the carb. I did a search on this forum and it did give me a bit of confidence and know-how on what to do, but I wanted to ask specifically. I've rebuilt my Stihl 290 farm Boss carb. Should the 50 HP Johnson be much harder?<br /><br />3. I probably need to purchase a) repair manual (that's why I need the year of this model), and b) a carb kit.<br /><br />4. Another neighbor said that the "coil" could be bad. My plan of attack is to rebuild the carb and then if it runs "leave good enough alone".<br /><br />5. Is there a site that gives a good illustration of how a carb "float" works. Another person explained that the "float" was sticking possibly.<br /><br />I appreciate any advice.<br /><br />If interested, I'd be glad to post some before and after shots of the rebuild of the boat.<br /><br />Scalloping season starts July 1 and I hope to have this problem solved before then so I can take my wife and 3 kids out in the "new" boat.
I took it to a freshwater river (upriver -- I'm learning) and it ran beautifully. It was very responsive and would jump up on a plane instantly and run wonderfully without leaving hardly a wake. I ran the motor up and down the river for nearly two hours at various speeds. The motor appeared to be completely fine and "fixed".<br /><br />Bad news! My father-in-law (retired) took the boat back out to the flats while I was at work and he said it acted just as it did when we first took it out but it never got on a plane and ran full out.<br /><br />1. First of all, I'd like to know how the boat runs great one day (for hours) and then 4 days later, acts "sick"? <br /><br />2. My guess is that I need to rebuild the carb. I did a search on this forum and it did give me a bit of confidence and know-how on what to do, but I wanted to ask specifically. I've rebuilt my Stihl 290 farm Boss carb. Should the 50 HP Johnson be much harder?<br /><br />3. I probably need to purchase a) repair manual (that's why I need the year of this model), and b) a carb kit.<br /><br />4. Another neighbor said that the "coil" could be bad. My plan of attack is to rebuild the carb and then if it runs "leave good enough alone".<br /><br />5. Is there a site that gives a good illustration of how a carb "float" works. Another person explained that the "float" was sticking possibly.<br /><br />I appreciate any advice.<br /><br />If interested, I'd be glad to post some before and after shots of the rebuild of the boat.<br /><br />Scalloping season starts July 1 and I hope to have this problem solved before then so I can take my wife and 3 kids out in the "new" boat.