Store Links Mobile - Shop Now


1 of 2 < >


The iBoats Forums will be down for maintenance starting at 1 PM MST on 12/16/2017. The estimated amount of downtime is 3 hours. Thanks for being a part of the iBoats community!
2 of 2 < >

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

150 merc 1984 black max exhaust ports??

  • Filter
  • Time
  • Show
Clear All
new posts

  • 150 merc 1984 black max exhaust ports??

    my 150 has the thru prop hub exhaust, two just below lower powerhead cowl as usual. but it also has 3 each side of cavitation plate pointing down of course? none of my other merc have had these 6 ? or any other i see. any idea why i have them, sounds like i`ve got headers on it when coming off plane from high speed. perfect hole shape and looks like factory paint so i don`t think they are homemade.

  • #2
    Re: 150 merc 1984 black max exhaust ports??

    Merc Lower units have gratings just above the AV plate. Normally these discharge only water. Perhaps the exhaust seal in the top of the gearcase is missing or out of position. You might drop the LU and see.


    • #3
      Sign up today
      Re: 150 merc 1984 black max exhaust ports??

      I've seen people drill the midsection out just as you describe for better hole shot...does the same thing PVS would do on a prop or over the hub exhaust...without causing any chance for blowout of the prop. Doesn't help top end any from what I've heard..but will help your hole shot..and yes...its LOUD...sounds kind of mean though...the baffle is probably taken out of it too...this is all okay but can lead to premature wearing out of the midsection. They are probably about 1" in diameter??
      "I'm your Huckleberry..." "You ain't no Daisy..."