Welcome Guest - Sign Up today
Welcome Guest - Sign Up today
Store Links Mobile - Shop Now



Help Tip: If you have a question that has not been answered to your satisfaction in the archives, it is always best to start a new thread of your own. By starting your own thread, you will receive the maximum number of views by forum members.

Below are some additional forum policies in hopes of all iboats members will follow, Thank you.

1. Please do not reply to old topics or hijack existing topics. Old topics of a technical nature are like a library book, Please do not write in them.

2. Old topics should be considered archives and used for reference only. Please do not reply to them.

3. Do not take over someone elseís topic (aka hijack) with your own question, even if it is similar. If you have a question that has not been covered to your satisfaction in the archives, it is always best to start a new topic of your own.

4. If you have a question for the original poster (OP) and the topic is over 30 days old, send the OP a PM, he may not even visit the forums any longer, or may not notice your question in the old topic.

5. By starting your own topic, you will receive the maximum number of views by forum helpers that may not even notice your question when itís posted at the end of someone elseís topic. And those answers will be specific to your particular issue.

6. Please do not post to topics that have been inactive for more than 3 months unless you are the original poster. We have very active forums and any topic that remains inactive for that long should be considered "dead". It is especially confusing when there is an entirely new question posted to an old topic.

7. Posting at the end of any topic is considered to be hijacking the original posters topic which in turn subjects the topic to be closed if it continues to happen thus not making it fair to the original poster in the future had for some reason he/she needed to return for additional information or provide an update of the problem solved which is always welcomed within a reasonable amount of time frame.

8. Please note that you should see a red banner pop up near the bottom of each inactive topic asking you not to reply to old topics. The Red banner will read: Please note this topic has been inactive for 90 days. For the best results, please start a new topic.

Thank you all in advance for doing your part in helping iboats run a smooth ship.

Additional forum rules linked below.
See more
See less

1973 20 HP Johnson Outboard

  • Filter
  • Time
  • Show
Clear All
new posts

  • 1973 20 HP Johnson Outboard

    Hey Guys, Hopefully someone can help me with this. I just bought a boat and motor and it had sat up for 2 years. I found trash in the fuel pump and carburetor and cleaned it thoroughly. I also replaced the spark plugs and gapped them to .030. I replaced the fuel lines within the coweling. Now it cranks right up and runs for about 15 minutes and then becomes sluggish and starts to die out. It eventually quits and oh yea, I have to leave the choke open about halfway for it to run.... I am new to this so any advice would help..

  • #2
    Re: 1973 20 HP Johnson Outboard

    Does the spark look good on both plugs? Does it still look good after you've warmed up the engine and it dies? My guess would be a bad coil(s) that shows up when it warms up. Maybe you need choke because you're only running on one cylinder? Have you checked the compression?Is it pumping water OK? Maybe it's overheating.Those are my thoughts anyway...Brent


    • #3
      Sign up today
      Re: 1973 20 HP Johnson Outboard

      Could be overheating, John. If you haven't changed the water pump impeller, do so now. They are only good for a couple of years, including time that they are in storage.If you need choke to keep it running after warm up you might have missed some gumming in the carb orifices.Let us know what you find.