RePower E31C

[larossa]

Hi All,

Unfortunately, the winter in Michigan this year was brutal and it took its toll on my diesel engine. So now I have repowering to a Yanmar. I hated to part with my Bukh because it never ever gave me a problem. I putting in a Yanmar 3GM30F rated at 24 HP @3400 RPM. I am wondering if any E31 folks have this engine and what size prop would I use. I’m not sure yet if I can use a 2 blade or 3. Anyway any help would greatly be appreciated. Also, I have parts for a DV Bukh engine for sale, cheap.

Thanks again,

Brian
E31 hull #2
Metro Detroit area

 

[Glyn Judson]

What size prop?

Brian, Assuming that the Kanzaki KM3P transmission has a ratio of 2.61:1, then you'll need a 3-blade (yes it will fit), 13 X 12 1/2 X 1 Righthand. That will give you the factory specified 3,700 RPM at full throttle on flat water with no wind. Please do understand that you should never cruise for sustained periods at that speed, it should be never be more than 80% of that. In truth you can operate at full throttle but the engine will overheat and set the alarm off after approximately one hour of running, guaranteed. I have the same engine, transmission and prop as above and have suggested the same to several E31 owners with like power plants. The results have always been positive and the happy owners experience the full potential of their engines with no soot on the transom and no RPM's over 3,700. Let us know how it all works out. Cheers, Glyn, E31 hull #55, Marina del Rey CA

 

[Emerald]

I was hoping Glyn would have the info at his finger tips, and of course, he does! Having gone through this I want to add that do not, I repeat, do not let a prop shop or marina tell you to do something different. I went through this where someone asked me some questions, put numbers in "the formula", and the prop they said I should have (can't remember) was way different, and the bottom line is they were wrong. Glyn's specification is correct for our boats with that engine. It's a great combination. You're going to love it.

 

[larossa]

Repower E31C - Prop Size

Glyn & Greg,

Thanks again for the information, I’ve been so involved in modifying the engine bay area I almost forgot to get back with you guys. There is a big difference in the mounts for the Bukh compared to the Yanmar. But the prop info is exactly what I needed. It will save me lots of time and money. Any thoughts / recommendations on brand of propeller, Michigan wheel or Campbell Sailor?

Thanks again,

Brian
E31 hull #2
Metro Detroit area

 

[larossa]

I was hoping Glyn would have the info at his finger tips, and of course, he does! Having gone through this I want to add that do not, I repeat, do not let a prop shop or marina tell you to do something different. I went through this where someone asked me some questions, put numbers in "the formula", and the prop they said I should have (can't remember) was way different, and the bottom line is they were wrong. Glyn's specification is correct for our boats with that engine. It's a great combination. You're going to love it.

David,

Sorry David I didn't mean to call you Greg.

Thanks again,

Brian

 

[Loren Beach]

"... and you can call me Al...."


Apropos the prop measurements. When we were trying to solve the problem of too much vibration in our boat's drive train, I took my new Michigan "Sailor" three blade prop to the local vendor with the Prop Scan franchise for a close-tolerance measuring. Turned out that the new prop was off by about a half inch of pitch on one blade.
He trued it up to spec and the vibration did indeed mostly go away. We still have some rattling at certain lower rpm's, but cruising speeds are very smooth.

The take-away is that unless the prop maker supplies a test printout for the exact prop that you are buying, do not assume that it's what it sez it is. I was later told that some other prop makers do a final measurement and put the form in the box when they ship each one, but that Michigan does not.

Considering how easy this is to do with a computer scan and a printout, I believe that they should do so.

Note that this all could have changed in the last couple years, either way. My experience, FWIW.

Loren

 

[Emerald]

David,

Sorry David I didn't mean to call you Greg.

Thanks again,

Brian

No worries - Greg's a good guy - I've been called worse :0

Buy the Campbell Sailor, because I always wanted to try one and I'd like the feedback! Seriously though, if I had not been given a prop to work with, I would have gone for the Campbell based on what I've read - always wanted to try one and I don't think you can go too far wrong. I don't think Michigan is "bad", but I think the Campbell has some innovation that would be interesting to check out.