Lower Unit Issues

[geekomatic]

Been awhile since I posted due to my workload.I've been making the big bucks for the Man, but none for me.<br />At any rate:This concerns my little 58 Fast Twin 18.<br />A few months ago I took apart my lower unit and discovered that the bearing retainer pin on my forward gear had been pushed down into the bearing housing. Bearing housing So I searched for five freaking weeks and finally found that little pin for a whopping $1.79.I bought three for good measure.I managed to drill out the old one and get the new one in place. new pin.Now, first of all-I know the new pin looks a little loosey-goosey sitting in it's new hole.That's OK.I'm not finished.I plan to shore up the pin and get it nice and tight with a little JB Weld or solder of whatever.Here's my issue. The new pin-hole and the new pin are dead-on-the money in the correct place.I verified this by placing the gear assembly into the housing after a temporary install with the pin.The thing fits like a glove. Gear in housing The holes all line up with the pins,etc.<br />The thing will not turn for squat once it's installed.I cannot turn it by hand using the drive shaft rod or the prop shaft.Everything is lined up fine and all of the gears are in great condition, as you can see in the photos.I can put the clutch dog in either neutral,forward,or reverse, and the gear assembly will not move by hand.It's almost as if that forward gear housing pin does not belong there. If I take that pin out and re-seat the gear assembly,It spins by hand normally with no resistence.Am I missing something? I'm not going to re-assemble this thing until I know it's OK.This is the only thing that is keeping me from cranking the motor at this point.Do I need to go searching for a new lower unit?

 

[Paul Moir]

Re: Lower Unit Issues

Good to see you back here! <br /><br />The pin is there to keep the forward gear bearing from spinning in the housing right? Is there a chance it's protruding too far and is pressing into the gear itself, jamming it? A little clay stuffed in the hole in the bearing should prove it.

 

[Xcusme]

Re: Lower Unit Issues

After looking at your 'new pin' photo, it looks like the drill walked a bit when you drilled out the old pin. Perhaps it's an alignment problem.<br />You might have a problem soldering the pin in the hole, as it's aluminum. Is there any chance to have a machine shop make you a replacement pin and do an interference fit?? Be sure to flush the drillings outta' the gearcase before re-assembly too! Good Luck, and report back on how things go.

 

[kidwalli]

Re: Lower Unit Issues

The pin is there to keep the bushing from spinning. Try grinding a SMALL amount off the pin and retry. You may have to fiddle it a few times to get it right. Horizontal position isn't super critical unless it is tipping the bushing and causing it to jam.

 

[Chinewalker]

Re: Lower Unit Issues

There is a hairs-width of space between the forward bearing and the housing. That ought to be snug, so something is holding it up. I'm with the others - the pin is sticking out too far and is binding up the gear through the bearing. <br /><br />- Scott

 

[geekomatic]

Re: Lower Unit Issues

OK.Here's the whacky thing.The reverse bearing housing ping sticks out WAY further than the one I just installed,so I don't think it's out there too far.I've messed around with the pin height,because I thought it may have stuck out too far as well.No matter how high or low I put that thing,I get no movement.Like I said,I have to clean up that hole a bit,and seat the pin into it with solder or whatever holds it.The new pin itself is an OMC part from Sierra, of which I bought three,just in case.For a $1.79, what can happen?<br />After drilling out the old one,I blew the crap out of the thing with an air compressor and the lubed it up pretty good with oil.The thing will still not budge,and I'm getting a bit pissed.<br />I'm gonna try Capt. Pauls' Trick with the clay and see what happens.<br />I'm starting to get a sneaky feeling that the bearing itself has actually become fused to the outer sleeve where the pin-hole is drilled.<br />At any rate,I'm already looking at a lower unit on Ebay.It's from a 7.5 fleet twin from 1957. According to the Seloc manual, It should fit on my 18hp.Weird thing that the 9.9 to 15HP lower units are diferent,because it seems I can pick those up all over the place.This is starting to become a bit confusing, but I still enjoy the learning process.<br />If I get a new lower unit,I swear I'm not taking this one apart.

 

[itstippy]

Re: Lower Unit Issues

"If I take that pin out and re-seat the gear assembly,It spins by hand normally with no resistence"<br />Huh. The front gear/bushing is spinning in the front bearing, right? NOT the whole front bearing spinning in the gearcase, with the gear/bushing stuck fast inside it. The front and rear bearings are stationary in the gearcase. They sit flush in the gearcase. The pins fit inside the slots (maybe your '58 has holes) in the bearings, to keep them stationary. Those slots/holes aren't very deep. Your pins (both of them) look way high to me. If they are higher than the slots/holes in the bearings can accomodate then they will cause everything to not line up properly with the pinion gear.<br />The whole propshaft assembly should sit EXACTLY the same in the gearcase whether the pins are in or not. If it doesn't, the pins are too high. <br />I rebuilt a '67 gearcase where some idiot had torqued the gearcase halves back together without aligning the pins with the slots properly, and drove the front pin into the housing just like yours. The pin stuck out about 1/16th of an inch. It was still enough left sticking out to line up the slot with what was left of the pin and put the thing back together properly. Works fine. You need very little pin sticking out.

 

[geekomatic]

Re: Lower Unit Issues

After a little closer inspection,I found more screwy stuff. I can take the entire gear unit with the prop shaft out of the lower unit and hold the forward gear bearing in one hand and try and spin the whole thing using the end of the prop shaft where the actual prop attaches.If I have the clutch dog in neutral or reverse position, I can spin the unit with no trouble.If I pop the clutch dog into the forward gear,it locks up tight,and the entire forward gear bearing tries to move with the gear itself.I'm beginning to think that originally the forward gear housing pin wasn't driven into the housing after all.I think it actually snapped off when the forward gear locked up in the bearing itself and the whole thing began to spin in the housing.Of Course, I never found any damage to the bearing,or any metal shavings, so I've managed to confuse myself even more.The whole assembly looks brand new.<br />Does this sound feasable, or do I still have no clue what I'm talking about?<br />Just to clarify- When this thing is assembled,<br />The pinion gear should engage and spin BOTH the forward and reverse gear depending upon the position of the clutch dog, Correct?<br />The forward gear bearing does not move when installed in the lower unit, but the foward gear itself should rotate within this bearing,hence the need for that little pin coming out of the housing.<br />If I'm anywhere near correct, then the entire forward gear bearing is just plain locked up and screwed.<br />You are all welcome to prove me an idiot, or encourage me pursue another angle of attack.Anything with moving parts is really starting to scare me,and I'm having second thoughts about the old airplane I've aquired for my next project.You can't just "drift downstream" if that engine stops.<br />Thanks as always for the tips.I really want to get this thing running.

 

[R.Johnson]

Re: Lower Unit Issues

Just looked at those pictures', what is all the crud between the teeth on the pinion gear. Is that JB weld on the front face of that bushing seat. I think you are forcing the forward gear, and it's bushing back into the pinion. I'll bet you don't have any fore, and aft play in that prop shaft at all. You should have some

 

[geekomatic]

Re: Lower Unit Issues

Yup.That would be JB Weld.The drill bit walked all over the place while drilling out the old pin.I had to fill it in and then sanded it down by hand using 1000 grit wrapped around a metal rod the same size as the housing.Worked like a charm.The goop all over the pinion gear is gone.I took the photo after drilling.I blew all the crap out with compressed air.It's squeaky clean now, trust me.<br />When I install the thing in the housing, I do have a bit of play in either direction.I suppose that's a good thing? It did worry me.I appreciate the tip.<br />Still have a suspicion I'll be needing a new lower unit......

 

[itstippy]

Re: Lower Unit Issues

"The pinion gear should engage and spin BOTH the forward and reverse gear depending upon the position of the clutch dog, Correct?"<br />No - the pinion gear engages and spins BOTH the forward and reverse gears REGARDLESS of the position of the clutch dog. The clutch dog engages either of these constantly spinning gears to make the propshaft spin clockwise or counterclockwise. If the clutch dog is in the middle, engaged to neither spinning gear, the propshaft is at rest and the gearcase is in neutral.<br />"The forward gear bearing does not move when installed in the lower unit, but the foward gear itself should rotate within this bearing,hence the need for that little pin coming out of the housing."<br />Exactly correct. It sounds like your diagnoses of the forward gear bearing being "locked up and screwed" is dead-on.

 

[itstippy]

Re: Lower Unit Issues

You do not need a whole new lower unit, you need a new forward bearing and a new forward gear& bushing assembly. Lower units where the gearcase is cracked/bent/sprung/destroyed from hitting something are common, and they have good gearsets in them. Keep an eye on eBay or check out the used parts places people recommend on this site. I don't think freeing up your seized parts is a viable option, but you can try.<br />The experts on this site can tell you what years are interchangable with your '58 for lower unit parts. Entire lower units are VERY interchangable for a long string of years, but the internal parts changed a bit (like holes instead of slots for the pins to fit in!).

 

[R.Johnson]

Re: Lower Unit Issues

By the way! that 7 1/2 HP gearcase won't fit on your 18. As has been pointed out, the forward gear must spin freely in it's bushing.

 

[geekomatic]

Re: Lower Unit Issues

Gentlemen,I have great news.At least for me.<br />MR. Itstippy,I got to looking at this obviously frozen unit.The housing is brass,I assumed.The bearing itself appears to be steel. I took a torch to it and heated the thing up.Can you guess what happened?<br />The gear popped out of the housing like it was lubed with warm butter! After cleaning it up and applying a little lube, it spins like nobody's business! I seem to still be in business!<br />As always, these tips are a Godsend, and I appreciate everyone's input. A follow up is soon.I plan on cranking this thing by next weekend.

 

[itstippy]

Re: Lower Unit Issues

That's great. You and I have similar restoration projects underway and I follow your Traveler related posts carefully. The guys on this site are incredibly knowledgable and generous. My first post ever was last October called "Gearcase Seal Kit cry for help". I had a '67 20HP gearcase in pieces and needed advice and encouragement. Paul Moir, Rodbolt, and Cajun555 saved my, um, lower unit. <br />You will be helping me in the Boat Restoration & Building Forum when I've got epoxy resin all over He** and need help from someone who's been there before the stuff sets and my fingers become permanently adhered to the keyboard.