Need tips on disassembling LU - force 85

[mrix]

Hello All,

picked up an 83 bayliner yesterday and now im disassembling the lower unit after loosing forward. I think i might have gotten an hour out of it.


So i've gotten the unit broke down till i can see the bearings on both shafts but i cant find any snap rings or anything to that nature. Seems like a void of information and in the internet - i cant even seem to find a manual to buy.

So far i've found a bit of larger metal junks so im guessing the gear is done or the linkage was off causing it to barely bite. Although the pieces ive seen so far are pretty small - I won't be able to tell anything until i can get this shaft out.


I dont want to have to resort to tieing it up to a tree with some straps and ripping the shaft out!!

any suggestions/advise would be appreciated!
-Mark

 

[mrix]

Re: Need tips on disassembling LU - force 85

pictures of where im stuck at.

 

[mrix]

Re: Need tips on disassembling LU - force 85

I finally got the unit apart.

the forward gear is shreaded. it looks like it was assembled incorrectly and the gears where not touching completely. i can tell because of the wear marks on the reverse gear.

The brass coupler that pushes the shaft also has excessive wear - indicating that the prop shaft was pushing against it with to much force.

From what i can tell (from bolt heads) i was the first person to be in here, so it makes me feel a little better that the seller didn't 'offload' his problem to me.

I'm not sure what to do at this point.
i ran it in reverse for a little bit and the teeth that feel off have been ground up like a pepper grinder - scratching up the casing.

oh boy - what a mess.

What a better bet - a used LU or a new set of shafts+gears?

 

[mrix]

Re: Need tips on disassembling LU - force 85

I'm still debating on if i should rebuild or replace.

For some reason the gears where not contacting correctly.

I see a gap in the bearing and its seat on the shaft, it seems to be the same gap that are on the wear marks.

Can anyone tell me if this gap is the problem? Can it just be pressed on completely?

 

[Frank Acampora]

Re: Need tips on disassembling LU - force 85

That gap is definitely the problem! Were there shims under the bearing cup pressed in the case? If there were none, the previous owner had the case apart and either lost the shims or did not put them in. He tried to compensate by raising the shaft by spacing the bearing. It should be tight against the land.
It did not come from the factory that way, and the bearing did not ride down the shaft by itself because the gear mesh tends to pull the shaft down. That's why the bearing is oriented in that position--narrow end down-- to take the downward thrust.
At this point, if all the gears are shot, you would probably be better off to buy a good used lower unit. Any one piece lower unit from any 85-125 hp engine from 82-89 will fit. Just be aware that the 85 and 90 hp have 2 to 1 ratio and the 125 has 1.78 to 1. If you use this lower unit, you will need to use a prop with 2 inches less pitch and you still will not get quite the same speed.

 

[mrix]

Re: Need tips on disassembling LU - force 85

Will this fit my power unit?

http://www.billphil.com/product_info.php?cPath=10&products_id=66

i spoke with the guy - he helped me get it apart, seems nice but he also told me the 89 gears would not fit, i do not know if this is true - he may be trying to get a sale out of me - but im not sure

Thanks
-Mark

 

[Frank Acampora]

Re: Need tips on disassembling LU - force 85

NO! Completely different. Two piece lower unit. Different bolt pattern, different water pump, different splines on prop shaft. Gears are beveled in opposite direction and can not be fit into your gear case.

You need one piece lower unit from 1982 up to 1989.

 

[mrix]

Re: Need tips on disassembling LU - force 85

Wow, thanks for the heads up!!

i'm looking for this shim - or where it should go, I don't seem to see it.

Posting pictures now

 

[mrix]

Re: Need tips on disassembling LU - force 85

I didn't find a shim on the shaft that would hold the gear down, not sure where it would go.

 

[Frank Acampora]

Re: Need tips on disassembling LU - force 85

Photos 4 and 5. The shims --more than one usually-- will be UNDER the bearing cup pressed in the case. They are critical to proper mesh of the gears. There is a special tool and procedure to shim the case but it can be done by feel. However, as I said before, it is probably better to buy a good used lower unit. The forward gear is about 280-300 new and the pinion is around 95 bucks new. Then add in seals, shims, and bearings and you are well over the price of a used unit plus you have the bother of putting it together again.

If you should find a reasonably priced lower unit with a missing skeg or broken cav plate, the shafts and gear pack can be put into your case. however, use all the mechanical parts and the shim pack from the broken case. You will probably be ok as far as mesh. If it is wrong, you will be able to feel it if you spin the shaft by hand with the water pump removed.

 

[Kajun37]

Re: Need tips on disassembling LU - force 85

save yourself some trouble and search all your local boat/motor salvage yards or buy a used one off ebay... do a search for "force outboard" or "force lower unit"....if you can wait till the fall you will get them alil cheaper...summer time they run anywhere from $275 to $375+..winter time they drop in price alil to about $250+

 

[mrix]

Re: Need tips on disassembling LU - force 85

THANKS for your help

i'd be SOL on information without it.

 

[mrix]

Re: Need tips on disassembling LU - force 85

if i can find the gears for cheap (less than 100) i will consider a rebuilt/patchjob
i can press the bearing down, improvise a shim if needed. if anyone had pictures of the shim or an exploded diagram that would be awesome.

but as of right now i am looking for a complete unit.

 

[mrix]

Re: Need tips on disassembling LU - force 85

Possible seller - he insists that this unit will fit my motor, it sure looks like it will.

Hi Mark,

Took some pics this morning in the rain. We are having a real storm.

Check the attached pics. The spline on the drive shaft has 15 splines.
Shaft is 23&7/8" from mounting flange.

I will add it to billphil.com this morning.

Bill
​

its not the previous one i was looking at.
http://www.billphil.com/product_info.php?cPath=10&products_id=86

 

[Frank Acampora]

Re: Need tips on disassembling LU - force 85

Now that's more like it! That is the one piece lower unit that will fit your engine. Good luck. Hope you get back on the water soon.

If the seller has not changed the gear oil and replaced the water pump inpeller, do so before mounting and using the unit---cheap insurance.

 

[mrix]

Re: Need tips on disassembling LU - force 85

should be here by friday - hope i have better luck this time.

thanks for your help!

im wondering if i shouldn't tear this one down and verify just as a precautionary measure... id hate to have this happen to me somewhere like the Detroit river!!

 

[Scaaty]

Re: Need tips on disassembling LU - force 85

I broke a driveshaft on my 88 125 about 4 years ago. I picked up a lower with a broke skeg, and pulled it all apart, then just replaced the shaft. I have a good set of gears, plus the Merc part numbers for repair seals/kits needed to put it back together.
If you want, and you are sure they will work on your 85 (pretty sure) I can send it off for $50 plus whatever shipping. Have to dig them out and see whats there. You will still have to shim it it correctly. My Seloc manual even covers it quite well. This way you will have a spare case..up to you. Email me at hogrider2@gmail.com if interested.. Robby

 

[Scaaty]

Re: Need tips on disassembling LU - force 85

should be here by friday - hope i have better luck this time.

thanks for your help!

im wondering if i shouldn't tear this one down and verify just as a precautionary measure... id hate to have this happen to me somewhere like the Detroit river!!

NO...just use it...only fix something broke!