• 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.
  • ALL iboats Forum Members and Guests:
    To show our appreciation for your participation in the Forums, we're offering an exclusive Forums-only discount good for an additional 5% off your iboats.com order for a limited time.
    To redeem, simply call our Customer Service Team at 800-914-1123 (Open M-F, 9am - 8pm Eastern Time) and mention the Forums 5% off discount. Offer excludes engines, trolling motors, and electronics.


Announcement Module

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 threads or hijack existing threads. Old threads of a technical nature are like a library book, Please do not write in them.

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

3. Do not take over someone elseís thread (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 thread of your own.

4. If you have a question for the original poster (OP) and the thread 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 thread.

5. By starting your own thread, 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 thread. And those answers will be specific to your particular issue.

6. Please do not post to threads that have been inactive for more than 3 months unless you are the original poster. We have very active forums and any thread 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 thread.

7. Posting at the end of any thread is considered to be hijacking the original posters thread which in turn subjects the thread 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 thread asking you not to reply to old threads. The Red banner will read: Please note this thread has been inactive for 90 days. For the best results, please start a new thread.

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

Honda 50 Lower unit Cracked

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

  • Honda 50 Lower unit Cracked

    My Honda 50(1999) has a piece(clamshell shaped) of the gearcase missing fron the back edge of the case and runs forward about 3.5"s. It is and 90 degree arc at the back edge and runs out just forward of the bearing retainer rear section. The retainer nut is cracked just behind the prop. The moter runs fine at low speeds, but cavites at 5000. the propshaft part stack is tight axially and doesn't wobble.
    Any thoughts on why this happened and is it a common Honda problem?

  • #2
    Re: Honda 50 Lower unit Cracked

    pretty common on motors of that age...corrosion builds up between the bearing carrier retainer and the housing and forces the housing out further and further until it pops out a chunk...seen lots of 50's do it..seen it on Mercs,Mercruiser,rare on Yammies but happens


    • #3
      Re: Honda 50 Lower unit Cracked

      Don't know, but my in-laws 40 HP merc had a similar hunk missing from the cav plate. The motor was used only for a couple of weeks on a lake. There wasn't any indication of trauma...just a clean break.

      We couldn't figure it out, but we started stretching our ideas to some sort of "harmonic vibration" that found a weak spot in the alloy...you know, kinda like the wine glass shattering with sound. Probably not a chance as to the reason, but it made as much sense as anything else!

      "New" '57 Lark Chapter One...the Find:

      "New" '57 Lark Chapter Two...the Initial Breakdown:

      "New" '57 Lark Chapter Three...the Gearcase:

      "New" '57 Lark Chapter Four...the NOS Powerhead:

      "New" '57 Lark Chapter Five...Repainting:


      • #4
        Re: Honda 50 Lower unit Cracked

        Your description is a little vague but if I'm reading it properly ,that sounds like freeze damage.Is that concievable?