1956 10 hp sportwin lower unit drive shaft

[chum1]

1956 sportwin m/n 10012 10hp

Hello guys I am going to try to get this motor going for a friend and as usual I have
some issues on identifying parts and correctness and was wondering if some of you might have some info.

1) compression was 72 on both cyl's with my gauge and there was spark so hooked up the pressure tank shot some fuel into cyl's filled a barrel of water and it ran!!........then backfired and died from overheat

2) after pulling lower unit off i discovered there wasn't anything to drive the impeller, someone looks to have welded a blob of metal for the key but it wasn't engaging.

3) could this be a different shaft that was modded? it is 26" long and looks to have been welded on, it will pull completely out of lower end, so i guess my question is "is this the right shaft?"

4) on one of the pics i took a straight edge and shoved the shaft completely in the lower end i put the straight edge across the flat surface and marked it with ink marker, I then pulled the shaft out and put it all the way into the engine side and marked it using the flat surface of the midsection, as can be seen from the marks there is about an inch play is that correct?

5) this engine calls for a 300611 pin to drive the impeller is this a 1/2 moon key or pin? and have any of you guys ground a slot on the shaft for it?

6) I know this is quite a long writeup but any help would be great, Thanks

 

[AlTn]

Re: 1956 10 hp sportwin lower unit drive shaft

looking at the diagrams for the gearcase at marineengine.com...it shows a drive pin for the impeller and both ends of the d/s being splined so yes, both ends should pull out...can be of no help with other ?'s

 

[oldybutagoody]

Re: 1956 10 hp sportwin lower unit drive shaft

I believe the part you are looking for is 300771 and it's kind of an all in one pin/key. It has a flat key side that fits into the keyway of the impeller and a round pin side that fits into the drive shaft. I would steer clear of cutting the drive shaft for fear of weakening it. The pin/key is only $1.74. Cheap.
http://www.marineengine.com/newparts/part_details.php?pnum=OMC0300771&ptype=&Engine=&Model=

 

[chum1]

Re: 1956 10 hp sportwin lower unit drive shaft

Thanks AIT

 

[chum1]

Re: 1956 10 hp sportwin lower unit drive shaft

That makes more sense i might just have to drill a hole for the pin, Thanks Oldy, this motor ain't dead yet

 

[F_R]

Re: 1956 10 hp sportwin lower unit drive shaft

Are you saying there is no hole for the pin now? Did they weld it shut, or what? When I first read this, I thought Aha!--the shaft is going into the gearcase too far and the pin is below the pump impeller plate. Could I be correct on that, or is there no hole at all?

If it is going into the gearcase too far, it is probable that the snap ring is missing or fallen out of the pinion gear. The drive shaft rests on that snap ring. Worse, that snap ring floating around in the oil an getting crunched up by the gears isn't too healthy.

 

[chum1]

Re: 1956 10 hp sportwin lower unit drive shaft

Hey FR you got it, the hole has been welded shut and i didnt know there was a snap ring that holds the driveshaft up on the pinion gear, looks like i will have to tear apart and reseal the lower end fixing that now ....

 

[oldybutagoody]

Re: 1956 10 hp sportwin lower unit drive shaft

I'm having trouble understanding why anyone would weld over the hole for the impeller pin. Is it possible that the pin just sheared off and the pin half is still in the hole? Did your driveshaft break and someone welded the whole thing?

Hey FR you got it, the hole has been welded shut and i didnt know there was a snap ring that holds the driveshaft up on the pinion gear, looks like i will have to tear apart and reseal the lower end fixing that now ....

 

[nwcove]

Re: 1956 10 hp sportwin lower unit drive shaft

I'm having trouble understanding why anyone would weld over the hole for the impeller pin. Is it possible that the pin just sheared off and the pin half is still in the hole? Did your driveshaft break and someone welded the whole thing?

sounds like oldybutagoody is on the right track, no logical reason to weld the hole over, probably just sheared and rubbed enough to look like its been welded.

 

[chum1]

Re: 1956 10 hp sportwin lower unit drive shaft

Thanks for the help, opened up the lower end and heres the guts of a 56 model:



as it turned out the snap ring was gone and snap ring groove on the pinion gear was about non existent:



So I had to grind down a washer and pound it in with a interference fit:



Sure enough the impeller pin shear'd and half was sticking in the hole i used a punch, a 3/32 drill then a 1/8 inch drill and it lifted out



the seals i couldnt find for the 56' model it seems the kits start at 58' so for the lower unit i just went to the bearing store and they measured out the prop shaft and drive shaft seals and i ended up using new timkin 471442 and 471264 which fit fine, the shift shaft seal, orings and spaghetti seal were easy to get.
Put it all together with aviation permetex after cleaning, installed new impellor with vasoline (pin lines up like it is supposed to now) the lower end shifts and works beautifully, Thanks you guys.

 

[AlTn]

Re: 1956 10 hp sportwin lower unit drive shaft

thanks for posting the seal no.'s..may help someone else down the line

 

[oldybutagoody]

Re: 1956 10 hp sportwin lower unit drive shaft

Good to hear you got it all fixed. I have a '57 Fastwin and that Prop Seal was a pain to come up with.