Re: Johnson 28hp choke not working
You mentioned that the electric choke activates as soon as you turn the key on. That suggests to me that you have a defective choke switch.
Since your choke switch is probably in a small panel next to your ignition switch, in the dash of your boat, look at the back side of it to see if you can get at the wire terminals. If not, you may have to remove the panel and pull it out of the dash a bit, so that the terminals are exposed. Once you gain access to the terminals, remove one of the wires from the choke switch.
At this point, the circuit to the electric choke solenoid will have been interrupted and it should not work. Make sure that your manual choke lever is in the open position, and turn your key to the on position again, to confirm that the solenoid has not activated. If this is the case, I would say that you need a new choke switch.
As to whether or not this is the complete problem, I can't say. As was mentioned, even with the choke closed, a motor should start when cold and will often start even when warm. In either case. a closed choke will probably make it quit eventually, but you usually see some signs of "life." You may have a dirty carb and that can be true even if the motor was running fine. All it takes is for a bit of junk from the tank to end up in one or both of the needle valves and you have problems.
Once you get your manual, read through it from start to finish without worrying too much about understanding everything that is there. You can then go to the sections on the choke system and carburetor to study them. If you decide to do a carburetor rebuild, I suggest that you find a helper who has some familiarity with outboard motors or other 2-stroke motors. Short of that, just find someone with good mechanical apptitude to assist you. I think you can learn how to fix your motor in time, but right now, it sounds like you're not ready to "fly solo."
One thing that I would do, however, before getting into anything beyond checking the choke switch, is to do a "spark check." It is very easy to do and serves to confirm that you have ignition to the park plugs. Remove both spark plugs and place one of them back in the spark plug boot for its respective cylinder. Ground that plug to the powerhead with a wire that has alligator clips on the end, or by stripping the ends of a piece of wire, so that you can wrap one end around the outer base of the plug and attach the other end to a suitable ground on the motor. Now engage the starter with the key switch - make sure no one is touching any part of the spark plug lead (either one) or the spark plug when you do this. If you get a nice "fat" spark, you know that cylinder's ignition system is functioning.
Now repeat this exercise on the other cylinder. If you again see spark, you know both cylinders are getting spark. While you motor could be out of time for some reason, this probably isn't the case, just because of the way the motor is set up (more on that at another time, if you wish). This leads to the conclusion that you have a fuel problem, which will most likely be either your carburetor or your fuel pump.
On the other hand, if one of the cylinders does not show spark, the problem may be confined to the ignition system. Fixing most of it is also an item for a later discussion, but there is one simple thing you can check - the spark plug on the offending cylinder. If one shows no sign of spark, take the one that did, and put it in the spark plug boot for the cylinder that didn't work. If you now see spark, the other plug is most likely bad. If there is still no spark, chances are that you have a problem in that cylinder's ignition system prior to the plug.
BTW - when you put the spark plugs back in, be sure not to crossthread them and don't over-tighten them! See your manual - maximum torque when doing so is only 17-1/2 to 20-1/2 foot pounds!
The good news is that your Johnson 28hp (of the early sixties series, not the later version) is a very simple engine. You don't need a lot of exotic tools and meters to troubleshoot and fix it. Take things lsow and get advice and you will be fine.
Welcome to iboats!
