1972 E27-Fixing Everything

[indigo]

Key Stock

McMaster Carr had some nice 18-8 stainless that is slightly under size.

92530A136, 18-8 Stainless Steel Machine Key Stock, Undersized, 1/4" x 1/4", 12" Long

If a customer wants one with a prop, this is what I use. They also have full size brass.

Tom

[ndutton]

Two recommendations:

1. Match the key material to the shaft as close as possible. Bronze shaft = brass key. You want to minimize dissimilar metals the best you can.
2. Dimple the shaft where the set screw lands with a drill.
   • Slide the coupler onto the shaft where you want it
   • mark the set screw location through its hole in the coupler
   • remove the coupler from the shaft
   • drill the dimple in the shaft (I always liked using a 5/16" drill bit for this)
   It's extra work for sure but makes for a superior installation.

[CajunSpike]

Moyer staff.... will your split coupling mate up with the 3 bolt engine coupling half as is?

To explain better, if I keep the original coupling half bolted to the motor, will the back half you sell, correctly attach to it.

Diameter of current coupling is 3/4". Key appears to be 3/16th.
Original rear coupling has 3 holes for bolts to pass thru, not threaded.
Front 1/2 has 3 threaded holes. Bolts have 9/16" heads.

[Administrator]

Forwarded to Don.

Bill

[CajunSpike]

Since ya'll have been patient enough to read this and help, time for the photos.

Slid the drop light in the engine box. First good view of the subject. Back wall intact. Ventilation fan was removed.


Wide angle shot of engine box. Back wall intact. Batteries are under door to left.


Straight down view of coupling. Back wall cut.


Side view after coupling removed and engine moved. Back wall cut. Muffler system and water line removed.


Straight down view after coupling removed and engine moved. Back wall cut. Notice how close the shaft keyway is to the water seal.
This proves the shaft is further back than usual. Hate to think what would have happened if the shaft backed itself all the way out.


The source of this discussion. The key is yellow. Its WAY too short for what I think it should be. I called it brass. What you you think? Key size is either 3/16"(probably this) or 1/4"
Prop shaft is stainless steel as far as I can tell. Isn't the key supposed to be softer material than the shaft so it can shear on impact?
If both are steel, there is no shearing ability right? The hole in the pin bolt was clogged with trash. This proves there was no safety cable installed. Its been opened in this pic.

[CajunSpike]

Just placed order with MMI.
New solid coupling 3/4".
New impeller.
New water pump gasket.
New exhaust pipe gasket and bolts.

Should be able to put this back together, no problem.

[CajunSpike]

Ran into a problem.

The original coupling is 3/4" opening for the shaft. Repeatedly measured, of this I'm sure.

The key that it uses is 1/4" square rod.

I know this because I bought a 3/16" key and it was too small.
Swapped the 3/16" for a 1/4" and the 1/4" key fits perfect.

The coupling I bought from Moyer that is 3/4" only comes with a 3/16" keyway.
Called them and cancelled the order this morning.

Anybody knows where I can find an A4 coupling for 3/4" shaft using a 1/4" keyway?
Old part is reusable if necessary but I'd rather replace it.

[ndutton]

Either find a local machine shop capable of broaching or clean up the old coupler.

[Al Schober]

The 'key' is that the key fit the shaft well. If the shaft has a 1/4" keyway, then you want to use a 1/4" key. It should be a press fit into the shaft. The part of the key that fits into the coupling can be cut down to 3/16". The key can be a bit loose in the coupling with no issues.

[CajunSpike]

So you're suggesting using a 'dual size key'? Like half of it being 3/16 and the other half being 1/4?

Don't know if it exists like that short of a machine shop making one.

[edwardc]

Found these, but neither specify the keyway width. Guess you'll have to call them. Both appear to be a Buck Algonqun part, specifically for the Atomic 4.

https://propshopinc.com/3-1-2-solid-shaft-coupler-buck-algonquin-3-8-bolts-mc350-p14.html

https://www.generalpropeller.com/solid-coupling-50mc350075&filter=ATTRIBU=0.750%2526quot%253B=21=Shaft+Size@@ATTRIBU=Universal%252CAtomic4=31=Transmission

[CajunSpike]

Ok, I'm an idiot.

Was about to post a photo showing the size of the hole in the coupling, that it was 3/4".


The only problem is that I'm using a printed ruler and I didn't start at zero. Started at the edge of the paper.
Starting at zero, the coupling hole is 7/8".

The Moyer part for a 7/8" shaft DOES include a 1/4" keyway.
I'll go back to my closet now.


After the fact note for future reference:
My shaft IS a 3/4" shaft. It also has a 1/4" keyway.

Was unable to find a new coupling with these parameters.

Ordered a 7/8th coupling with 1/4" keyway thinking that was the right size. Did not use it since shaft did not fit right, went back with original part.
:-(

[tenders]

FWIW I think the split coupling is a huge and worthy upgrade. Getting a sound shaft out of a sound solid coupling in tight quarters is a terrible horrible no good very bad job.

[CajunSpike]

Spent several hours in the boat last night, a/c unit in the door.

Prop shaft had backed out 4 inches on its own.
Got coupling reinstalled.
Shaft key reinstalled.
Pinch bolt sitting in shaft detent.
Pinch bolt tightened hard and wired in place with heavy copper wire.

Shoved the motor back into place, got a few mount bolts into the floor.

Had tried installing 3 new coupling bolts but they were too long.
They went thru the coupling and pressed against the trans housing.
Removed those and went back with original non rusty coupling bolts.

Removed water pump cover to change the impeller.
Had bought 2 paper pump cover gaskets cuz I didn't know which pump I had.
Come to find out neither gasket fit because the pump cover was the type
held on by thumbscrews and has a thin rubber o-ring type seal.
Apparently its an MMI water pump door kit.

https://moyermarine.com/product/mmi-back-plate-kit-csob_10_370/

So now I have 2 untouched paper water pump gaskets but really need the o-ring type seal.

Guess which is the old part?

Had to gently beat the old impeller copper center ring off the pump shaft.
Shaft in great condition.
All 6 'ears' of the impeller were 1/2 way separated from the base.
Installed new impeller and closed up the back plate of the pump.

Hooked everything up but ran into two issues that I left unfinished.

Having problem lining up the exhaust pipe. Got one bolt and new gasket in. Have to twist the fitting slightly to align the 2nd bolt and hole.
I think the solution to this is to use a rope to pull up the standpipe slightly thus twisting the exhaust pipe just enough for it to align. Appears to be some weight on the pipe causing it to twist.

Also the rear sink side engine mount twisted a bit, so the bolt holes don't align with the holes in the floor.
For this, I can lift the engine slightly with a come-along, realign the mount and drop it back into place.

So other then the exhaust bolt and floor bolts, everything is back together including the new electronic points and coil.

[alcodiesel]

I don't know, Bill, but there might be a few more seconds left in that impeller. Actually it looks like you got it out just in time. Now c'mon up to Norfolk and hook up a new exhaust pipe for me.
Thank you for documenting what you are doing.