Another Tread prompts this : Feathering prop on my Yanmar 2GM

[Refueler]

Sorry but its only picture I have of the folding prop ....

The prop works fine - but as we all know - the prop 'throws' its blades out due to centrifugal force (I'll ignore that in College - we were told that Centripetal force exists etc).

Fine. But mine does it with quite a bang ... first the gearbox CLUNKS ... then prop BANGS ... not ear-shattering - but loud enough ...

We checked prop pivots when out of water etc and all are good.

 

[Tranona]

What is the question? Yes, some are noisy, but others like the Flexofold I had are not. Does it have buffer inserts to cushion the noise?

 

[Refueler]

No - its plain ....

Question ? Looking for others comments as to whether they have similar ...

 

[B27]

I've sailed boats with the 1GM.
These have AIUI, a 'dog clutch gearbox'.
Clunk, it's in gear.
Most other gearboxes are some sort of servo-clutch with a more subtle take-up of the drive?
I don't know what a 2GM has.

My folding prop looks very similar, but the blades are pretty tight on the pivot pins and the pins are locked to the body.
Going ahead, there is a bit of a 'thunk' as the prop unfolds.
I generally try to move the throttle slowly to minimise this.

Motor-sailing, or in bigger waves you can get the situation where the boat overtakes the prop and the blades fold a bit then hit the stops again, rattling a bit, I try not to let this happen.

 

[Refueler]

That's about it ... the 2GM has similar ..

My PRM of course is hydraulic on the Perkins and I like that !! Yes you get a slight ... hard to call it a clunk ..... as it engages .. but nothing like the Yanmar I have.
Must say - its not as loud as the AQ280 on my MoBo ... that lets you know its in gear !!

 

[Tranona]

The Yanmar box is common on the GM range and yes it clunks into gear, but so does my mechanical PRM. Volvo boxes (at least on the saildrives) seem more refined. You don't say what make of propeller it is but the buffers on the Flexofold are there for a reason flexofold.com/folding-propellers/shaft-propellers/2-blade-shaft-folding-propeller and from what I can see other designs do not have these relying on metal to metal contact.

 

[Refueler]

I have no idea what make prop it is ... no markings when I looked ... she's in water now so have to wait till lift out.

Pals B31 with YSE (1GM) clunks but not as loud..

 

[GEM43]

The Yanmar box is common on the GM range and yes it clunks into gear, but so does my mechanical PRM. Volvo boxes (at least on the saildrives) seem more refined. You don't say what make of propeller it is but the buffers on the Flexofold are there for a reason flexofold.com/folding-propellers/shaft-propellers/2-blade-shaft-folding-propeller and from what I can see other designs do not have these relying on metal to metal contact.

To that can I add that I’ve recently replaced the shock absorbers on my Flexofold. They were eight years old. The new ones are noticeably thicker than the old ones and they have definitely reduced the “bang” to a “thud” upon engagement.

 

[Tranona]

I have no idea what make prop it is ... no markings when I looked ... she's in water now so have to wait till lift out.

Pals B31 with YSE (1GM) clunks but not as loud..

YSE and 1GM are totally different engines and gearboxes. The Kanzaki gearbox is very sensitive to the lever/cable attachment being just right. There is a section in the workshop manual on how to set it up. Vaguely remember doing it when I installed my 1GM over 30 years ago.

 

[GEM43]

. The Kanzaki gearbox is very sensitive to the lever/cable attachment being just right.

I’ve just had to have new Kanzaki gearbox fitted because it wasn’t setup correctly, it killed the cone clutches.

 

[Refueler]

YSE and 1GM are totally different engines and gearboxes. The Kanzaki gearbox is very sensitive to the lever/cable attachment being just right. There is a section in the workshop manual on how to set it up. Vaguely remember doing it when I installed my 1GM over 30 years ago.

Its funny you say YSE is not 1GM ... because that caused my pal a lot of grief ... he's a first time boat owner and 'knows all' .....

I'm a long term boat owner and still learning !!

 

[Tranona]

The 1GM originally notionally 8hp was the start of Yanmars serious entry into the small leisure market and spawned a whole range of engines. The YS series was its prededcessor and an adaptation of its fishing boat engines. The physical differences are obvious as is the user experience particularly the effect on the ears and tooth fillings!