• If this is your first visit to the iboats.com Boating Forums, be sure to check out the FAQ. To post a question or comment, begin by signing up. To start viewing messages, select the forum that you want to visit from the selection below.


Announcement

Announcement Module
Collapse

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.
http://forums.iboats.com/forum-rules-guidelines-405/
See more
See less

Mercury 500 50 HP Power Problem

Page Title Module
Move Remove Collapse
X
Conversation Detail Module
Collapse
  • Filter
  • Time
  • Show
Clear All
new posts


  • Mercury 500 50 HP Power Problem

    Hi,I have a Mercury 500 50 HP 1976-1979 model with the symptons as follows:Starts OK, runs OK for anywhere from 5mins to 20 mins then the motor cuts out while running fast (ie. 1/2 to full throttle). I can then start the motor and it idles OK but cannot apply any throttle beyond just over idle otherwise it cuts out. After leaving it a while it seems to be OK then can apply more throttle and continues to run OK until the symptom appears again.Any help appreciated and thanks in advance.


  • #2
    Re: Mercury 500 50 HP Power Problem

    Sounds like fuel starvation. Have a passenger squeeze the Primer bulb during this condition to force the extra fuel reqd. to the pump, if that works then consider the following:Try installing a short piece of clear pvc line between the fuel pump and your main fuel line, this will allow you to monitor the fuel flow at high speed, which is of course when you need the most fuel. Do this on the water, unless you have a test wheel and a large tank. Its very hard on these motors to be reved high with out a load placed on the engine. By doing the above, you are confirming adequate fuel to the carbs. It could be that you have a air leak somewhere between the tank and the inlet side of the fuel pump (which would give more air than fuel) or your fuel pump could be worn out. I wonder if this is the original pump? You may want to rebuild it if it is 8 years or older regardless.Yes, you can have air leakage at a fuel connection and still not have a fuel leak. Fuel is more dense than air. Good Luck, Mike

    Comment



    • #3
      Re: Mercury 500 50 HP Power Problem

      I concur with Evin300. But I wanted to add while underway ,with motor giving you grief, remove the gas cap. If it takes off like a drag boat, it's a venting problem. The tank must get air to replace the fuel the motor burns.
      "Did you hear about the guy whose whole left side was cut off? He's all
      right now."

      Comment



      • #4
        Re: Mercury 500 50 HP Power Problem

        Good point 12Footer, Could it also be a faulty check valve in the Bulb Primer? Or what if valve doesnt work at all? stuck open?

        Comment



        • #5
          Re: Mercury 500 50 HP Power Problem

          If the check ball doesn't close,the bulb wont pump up hard, Mike.
          "Did you hear about the guy whose whole left side was cut off? He's all
          right now."

          Comment

          Working...
          X