Re: Prop is spinning freely


Bill K,
Thank you for this clear explanation of the Hurth/ZF transmissions. I haven't read this anywhere before and have never understood why my helm has a sign that says in French, not to put in reverse while sailing. When I switched from AutoProp to be MaxProp, I read that I should put in reverse until it stopped turning, then back to neutral. I have just finished a maintenance of the Autoprop and reinstalled it to see how it performs compared to the MaxProp.  I now know that if it turns while sailing, it is safe to put the transmission in forward, but not reverse.

Now for the next question...
When I repowered from Volvo TMD22 (78HP} to Yanmar 4JH4HTE, (110HP), I was assured by the Yanmar dealer and mechanic (Danny Ramos in Fajardo; top Volvo mechanic in the Caribbean at the time) that the existing transmission was ok to reuse.  It has had no problems after ~1200 hours using the MaxProp.  But now I am worried that it may not be quite up to the job.  Does anyone have thoughts or recommendations about that? 

Should I just replace it with a new, more
robust one? If I use the Z25F, that means adding a shaft brake, right? Are there other robust mechanical transmissions that wouldn't require the brake? Any downsides to that?

Or have the transmission inspected, and put it back in if everything looks OK?

Or, with 1200hours already on the transmission with the new engine, just assume it is Ok and leave it alone?

Thanks again Bill K, your post is a game-changer for me!

Happy New Year, everyone!
Kent & Iris
SM 243

Kent & Iris

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