37c Prop and shaft for 2qm20

K

kwaai

.
Apr 5, 2014
11
hunter 37c la paz, baja
Advice please,
I had my shaft snap, so I am looking to replace the shaft and have a 2nd as a spare.
I am also looking for 2 props, my old 2 blade is looking poor.

From my research I believe I heed a 1" shaft x 52"

and a 2 blade prop 15 x 16

anyone had experience with a 3 blade - what size is best for the 3 blade?

I will be driving from Baja, through California and then on to sc, so anyone who has an idea of where I could stop along the way to get suitable parts, I will appreciate the help.
 
Jim Legere

Jim Legere

.
Jun 8, 2004
1,065
C&C Frigate 36 St. Margarets Bay, Nova Scotia
kwaai said:
Advice please,
I had my shaft snap, so I am looking to replace the shaft and have a 2nd as a spare.
I am also looking for 2 props, my old 2 blade is looking poor.

From my research I believe I heed a 1" shaft x 52"

and a 2 blade prop 15 x 16

anyone had experience with a 3 blade - what size is best for the 3 blade?

I will be driving from Baja, through California and then on to sc, so anyone who has an idea of where I could stop along the way to get suitable parts, I will appreciate the help.
Click to expand
I replaced mine with a 1" SS shaft from a Hughes 38; I don't recall the length, but I had it cut shorter to fit in a machine shop. Consider getting a new coupling hub for the new shaft. I still use the original 15" x 16" RH prop, but that is with the 3QM30 in my case. Not sure about using a 3-bade with the 2 cylinder engine, but others will chime in.
 
B

Blaise

.
Jan 22, 2008
359
Hunter 37-cutter Bradenton
Midnight Sun Originally had the 2qm20. My original prop was a 17x13.
 
rardiH36

rardiH36

.
Jun 21, 2007
2,117
Hunter Cherubini 36_80-82 Sausalito / San Francisco Bay
kwaai/Blaise:

First of all, everybody else please continue to give kwaai information in response to his question. But ...

... for kwaai and Blaise - I have never been on another boat with a 2QM20. Mine is fitted with one. It starts and runs just fine. No smoke and I think full power is still available, so I expect it to keep pushing the boat along for quite another few years. However, it does vibrate rather significantly. I've just shrugged it off to the normal characteristics of a 1979 built "2-banger". My prop is balanced and the engine/shaft alignment is fine. I thought to take the opportunity of seeing a couple of 2QM20 folks on the same post to ask if can you describe for me how your engine(s) do in respect of vibration? kwaii, now of course. Blaise, maybe per your recollection.

regards,
Rardi
 
woodster

woodster

.
Sep 15, 2009
6,243
S2 9.2a Fairhope Al
kwaai said:
Advice please,
I had my shaft snap, so I am looking to replace the shaft and have a 2nd as a spare.
I am also looking for 2 props, my old 2 blade is looking poor.

From my research I believe I heed a 1" shaft x 52"

and a 2 blade prop 15 x 16

anyone had experience with a 3 blade - what size is best for the 3 blade?

I will be driving from Baja, through California and then on to sc, so anyone who has an idea of where I could stop along the way to get suitable parts, I will appreciate the help.
Click to expand
\
i had mine made at General propeller in Bradenton Fl make sure you have your shaft with you so you can answer any questions they may have ...just makes it a lot easyer.......

regards

woody
 
B

Blaise

.
Jan 22, 2008
359
Hunter 37-cutter Bradenton
Ah, the 2QM20. I replaced mine in 1991 with over 4000 hours on it. Why? Simply because I was being transferred to Puerto Rico, and didn't want to replace it down there. 2014, it is still running perfectly with a gillion hours on. It used half the fuel my 3gm30f does and would easily push midnight Sun into the low 8's. I have missed it every since, with the exception of the vibration. At idle, the entire rig would shake. It sounded like someone hitting an anvil with a 10 pound hammer. The vibration if inherent in the engine. Just live with it. The other good points are worth it.
 
rardiH36

rardiH36

.
Jun 21, 2007
2,117
Hunter Cherubini 36_80-82 Sausalito / San Francisco Bay
Blaise:

Many thanks for the useful (and quick) reply. Yes my entire boat, as your 'Midnight Sun' did before your re-power, pulsates when the iron propulsion plant is operating. (However, at 2200 rpm, the harmonics tend to cancel out quite significantly.)

At some point, I was thinking first to tune the injection timing (which I have read can cause vibration if the the various cylinders aren't getting the pulses of fuel at the right time and in the right air/fuel mixture ratio). And second to get around to replacing the engine mounts (which on inspection don't look that bad). But either one is logically difficult for me to do (since unlike you folks on the doing countless hours motoring along the Inter-coastal Waterway), the average duration of motoring on each of my outings onto the central SF Bay might be only about 20 minutes. All the rest of motive force on most sailing days is wind -- courtesy of the infamous "the slot".

Now, I will regulate my two contemplated "remedies" much further down in my life's priority list! And just live with it.

Again thanks,

rardi
 
A

Alctel

.
Dec 13, 2013
264
Hunter 36 Victoria
Mine shakes and thumps an awful amount at low RPMs - higher RPMs are relatively smooth though (yet noisy)

It is however as mentioned surprisingly full efficient and speedy
 
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