Driveshaft binding up crank on v4?

[rothfm]

I know there are threads on this type thing, but since the upgrade it appears theres only an overall search, not in each section. Here Goes!

My 1993 115 blew up...So happens, I had a 1984 Powerhead measured, machined & Ready to put together. It came out nice. This is temporary until my other is rebuilt.

ISSUE: The 1984 PH sits down nice, everything lines up. But when I Install the LU, it creates a bind, and its hard to turn the flywheel. It appears to go all the way in fairly easily too.

Is there a Shaft length difference? I dont have the original 1984 Lower/Shaft to check....Maybe a difference in the shape on the inside end of the crank that accepts the shaft? Or just a slight length issue for the end of the '84 crank?

It clearly gets better to turn, as I back off the LU a small amount. Removing it altogether, the Flywheel spins freely.

Hoping to overcome this, so I can test start, break-in and get back to Fishing soon!

 

[rothfm]

To be clear, all is original 1993 (j115txats), except mounting up a temporary 1984 PHead that was rebuilt by me.

 

[emdsapmgr]

Just before you mounted the new powerhead, did you liberally grease the driveshaft splines and the mating splines on the crank end?

 

[Will Bark]

and did you put any grease on the top of the driveshaft which is a no no.

 

[racerone]

There is a difference in the bore of the older crankshaft !!!-------This swap will not work unless you cut about 1/8" off the top of the driveshaft.------How do I know you would say ?

 

[rothfm]

I was carefull not to put grease on the top of the shaft. Just a bit on the splines. I cant say if there was a residual glob however up inside the crank and. But the lower does seem to slip in fine.

1/8"...Was wondering about that! I mounted and remounted that head, and all but a couple times it seemed to be able to "rock" just slightly as if the top of the shaft was "bottoming" out in the crank end.

Is this my problem? Too much downward pressure binding things up.. You can really hear the impeller working when turning by hand. I took it apart and no issue down there. Even lubed the inside of the impeller cup a bit to see if it helped.

1/8" huh? I could try that and it shouldnt hurt my '93 when I get that rebuilt right?

Big thanks

 

[racerone]

This is so simple to check out !!----Loosen the bolts and drop the lower unit 1/8" and you will see.

 

[rothfm]

Yea, pretty sure when I loosed the lower it turned fine. I'm going to remount the lower now as a double-check and leave a small gap to see. Let all know.

 

[racerone]

Newer crankshafts have a different seal arrangement up top and no O-ring groove on the newer driveshaft I believe.---This is classic ----" it looks the same , but it is not the same " type stuff.

 

[rothfm]

UPDATE/Resolved:

Dropping the LU a bit did verify the F-wheel frees up. So I did take off 1/8 or so off the top of the shaft and bevel the edges. Same result. I then ground off just a bit more, Same result.

Looking at it carefully I believed it was in fact the "shoulder" just below the splines. After the splines there is an area that "bumps" out a bit thicker for about 1 1/2 - 2 inches. I really believed it was the top of that thicker area or shoulder that was hitting in the crank. This LU does not call for an O-ring there.

I took off 1/8 off the top of that shoulder-around the circumference, to make it the same thickness or a bit smaller than the splines area...and that did the trick. LU up nice and tight, and no binding.

AND, the 1984 Powerhead I rebuilt cranked up and ran real nice. Very pleased. This looks like a good viable powerhead until I can rework the original 1993 when I have the extra money. Some more testing, button things up...and Back to fishing!

Thanks to those who contributed.