• Untitled Document

    Join us on March 29rd, 7pm EST

    for the CBEC Virtual Meeting

    All EYO members and followers are welcome to join the fun and get to know the guest speaker!

    See the link below for login credentials and join us!

    March Meeting Info

    (dismiss this notice by hitting 'X', upper right)

Martec Folding Prop and shifting RPMs

markalan

Member II
I just purchased for my Olson 34, a Martec Folding Propeller. The operating note indicates shifting into gear at not much more that 600 RPMs. I have the Universal M25XP. I have read that I should not set the Idle below 1,000 RPMs. Is there a difference between engine RPMs and Propeller RPMs?
Am I missing something?

I would appreciate if someone can shed some light on this.

Thanks.

Mark
 

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
Idle?

Given that these smaller diesels seem to idle at around 800 or 900 rpm (or thereabouts), reports from the field do not seem to generate any stories of prop wear.
:confused:

I used a Martec feathering ("Autostream") two blade prop on our boat for ten years. I sent it in once for a checkup and/or a rebuild and they said it needed very little work.
OTOH, I have never owned a folding prop, but know other sailors that have used one for many years with our same model of diesel, the 23 hp Universal M25XP.

I recall that the instructions for reversing, with our former featherer, advised shifting when at "idle", and warned that you could shift at higher rpm's in an emergency, but there was a chance of damage, too.

Loren
 
Last edited:

Mort Fligelman

Member III
Martec Folding Prop

First....my M25XP Idles at just over 800 RPM......and the Martec folding two blade has been on the boat since 2006.....no problems.

If you dig through my posts you will find I have always been a strong defender of Martec, as I have had them on four boats dating back to 1972.

Just use and enjoy it.....
 

footrope

Contributing Partner
Blogs Author
Don't most of these little boat transmissions have a 2:1 ratio? Your prop shaft is probably rotating at approximately half your engine rpm.
 

Grizz

Grizz
(another) +1 for Martec

Echoing Mort, there's a Martec folding 2-blade prop attached to the business end of a Universal M25XP that idles @ 800 rpm and has been trouble free (knock on wood).


It gets us out, and back, to harbor and the 3-second rating penalty is well worth the benefit, especially in light air.
 

footrope

Contributing Partner
Blogs Author
From the Martec website for the Eliptec Mark III:

OPERATING INSTRUCTIONS Forward
Engage only at idling RPMs. Damage may result if gear is engaged at much over 600 propeller rpm.

So, check out your transmission specs to see how to calculate your prop shaft speed from engine rpm. The testimonials from the others would bear out that idle engine speeds up to 1000 rpm are not harming their propellers.

http://www.martec-props.com/install_eliptec.htm

Martec Eliptec 600rpm.jpg
 
Last edited:

fool

Member III
Echoing Mort and Griz, 800 rpm at idle on th' ol' M25 and Martec folding prop, no issues currently.

If the tips touch when closed it's time to send back for reconditioning. Just had mine done and the service from Martec is quite good on turnaround time.
 

markalan

Member II
Don't most of these little boat transmissions have a 2:1 ratio? Your prop shaft is probably rotating at approximately half your engine rpm.

Great point! I do have a 2:1 reduction and therefore my propeller RPM Should be considerably less. I'm thinking that it should be fine.

Thanks to everyone for the timely feedback.

Mark
San Pedro, Holiday Harbor
 

markalan

Member II
Great point! I do have a 2:1 reduction and therefore my propeller RPM Should be considerably less. I'm thinking that it should be fine.

Thanks to everyone for the timely feedback.

Mark
San Pedro, Holiday Harbor

For further topic clarification, I thought I would add my discussion with Gary of Martec. "Gary, I just had the prop you sent me installed and I have a question. The MFGs minimum RPM is a recommended 1000. The Martec literature indicates close to 600. Please explain if I am ok to use at the MFG recommended min. RPM"

Response "If you can set it at 800 that would be just fine and most engines do well at that RPM".
 
Top