Amount of Time for Lower Unit Repair

[newport]

I would appreciate any response identifying how many hours are involved in removing a lower unit, replacing the propeller shaft, resealing and reinstalling the lower unit on a 1992 Johnson 150 HP v-6 outboard.

 

[wilde1j]

Re: Amount of Time for Lower Unit Repair

Saltwater motors are very hard to predict time, as some fasteners and the bearing carrier may come out very hard due to corrosion. Probably 2 to 3 hous w/o any problems getting apart.

 

[jegervais]

Re: Amount of Time for Lower Unit Repair

Warranty flat-rate for a prop shaft replacement is 4 hours. As previously stated, any corrosion issues will add to that time.<br /><br />-John

 

[newport]

Re: Amount of Time for Lower Unit Repair

Thanks Jim and John for the info. Although the engines are 92's there are only 120hrs of use on them so I'm hoping all is well inside except the prop shaft replacement. I was also advised to wire brush all seal surfaces, use an aviation sealer or permatex when installing the seals,change out the drive shaft bearing and use loctite on fasteners.Good recommendation?

 

[Solittle]

Re: Amount of Time for Lower Unit Repair

I'm curious why you are replacing the prop shaft. Just nosy I guess - -

 

[newport]

Re: Amount of Time for Lower Unit Repair

I was running @ 3500 RPM in plenty of water and no visible signs of obstructions. I felt this strong vibration and sudden loss of power and shut the engines off instantly. When raising the two outboards, the starboard side engine was missing the propeller and part of the propeller shaft up to the first (closest to the propeller) lower unit bearing housing. I am quite baffled by the experience since I went back to look for a trap or anything I could have hit. In addition there is no evidence of hitting anything on my lower unit/skeg. I am going to dive for the missing hardware and get everthing looked @ when I pull the boat out of the water next week.At this point I can only believe there was a weaking of the shaft in the past (previous to me owning it the skeg did have a small piece missing)and it fatigued. Any ideas /past experience?

 

[jegervais]

Re: Amount of Time for Lower Unit Repair

Newport,<br /><br />I've seen that exact scenario twice before. It is typically caused by improper torquing of the prop nut (too loose).<br /><br />As I understand it (from the factory analysis) is that the thrust bushing begins to spin, which heats up the prop shaft. This in turn eventually weakens the shaft and one day it shears off and, well, you now know the result...<br /><br />Be sure to install props with an accurate torque wrench. The correct torque spec for Johnson V6 models is 75 to 80 ft.lbs.<br /><br />-John

 

[rodbolt]

Re: Amount of Time for Lower Unit Repair

steel wire is not reccomended to use on any aluminium surface that may be exposed to saltwater. use a roto-loc, emery cloth or 3M pad but stay away from wire if possible. or use brass.<br /> on the seal OD's I use omc adhesive M or 3M super weather strip adhesive. the only place I use loctite is on the NEW pinion nut. unless the service manual specifies another use elsewhere.

 

[newport]

Re: Amount of Time for Lower Unit Repair

John, Rodbolt, Thanks for the great info. John, I am amazed at how this shaft could have failed and I believe you are right on the money. Nothing hit this prop.!!!I did not torque the prop nut when installing this spring, just tightened it up using plenty of grease on the shaft, spacer, etc that could have also given me a false tightness.<br />todat I again I discussed the repair /replacement of the lower unit with the marina mechanic . Because the water tightness of the lower unit has been compromised,(the lower unit oil started leaking out of the motor after the shaft sheared and it has been in the water for two weeks now), he is adamant about replacing the lower unit even with a used unit since salt has now got into all the bearings, cavities, etc, etc. Does this sound like the right step to take? Cost to replace vice repair is considerable , but I would rather fix it correctly the first time.

 

[v12mac]

Re: Amount of Time for Lower Unit Repair

I rolled the dice and picked up one used for $200 bucks on e-bay. But I don't run too far off shore and it was worth the gamble it has held-up great. Your call.<br /><br />Mac

 

[newport]

Re: Amount of Time for Lower Unit Repair

Thanks Mac. I would also be willing to gamble to get back in the water for now and then look into my own lower unit for repair during the winter....yes unfortunately the season ends Nov/early Dec here in MA.

 

[DHPMARINE]

Re: Amount of Time for Lower Unit Repair

Newport,<br /><br />I can't vouch for a 1992 product,or for a 'spinning' thrust washer.(although I have seen prop shaft galling from loose thrust washers.)<br /><br />I have read about composite material shafts.That is a shaft made from 2 types of steel.Maybe iron in the gear housing,stainless outside.I am not sure what materials.<br /><br />Where ever I read it it was OEM bombardier or merc.<br /><br />Maybe someone can 'back me up !' (make it a BUD)<br /><br />DHP<br /><br />I think the weld let go

 

[rodbolt]

Re: Amount of Time for Lower Unit Repair

DHP<br /> not sure of the metalurgy but quite a number of makers use a welded two part shaft. were the lower unit mine I would tear it down and inspect for damage. <br /> at least that is a very simple unit to repair.<br /> I do happen to have a few 225 units with 25" drive shafts about

 

[clanton]

Re: Amount of Time for Lower Unit Repair

OMC used to use a 2 piece shaft spun welded. They most always break at the weld. One of the reasons for 2 piece drive shaft on the larger engines.

 

[newport]

Re: Amount of Time for Lower Unit Repair

Thanks DHP, Rodbolt and Clanton for all the info. I am now looking for a good condition used lower unit for the Johnson, 1992 V-6,150HP, Silver Star Series,25 inch shaft,60 degree, RH rotation. If you have any leads ,let me know. Because my lower unit has now been soaked in salt water from the shaft damage , my mechanic is adamant about not rebuilding it.Looking @ the costs for a remanufactured /new one is prohibitive right now ...so I'm hunting in the boneyards.

 

[DHPMARINE]

Re: Amount of Time for Lower Unit Repair

newport,<br />I'm a bit confused. Did this damage just occur,or was it a while back?How long do you figure salt water was in there,to do alot of corrosive damage?<br /><br />If it just happened,I can't imagine that much internal damage from salt.Maybe your mech found other damage,like a spun pinion bearing ?<br /><br />DHP

 

[newport]

Re: Amount of Time for Lower Unit Repair

Hi DHP,The shaft failure occured two weeks ago and the lube oil started leaking out right at time of failure.I have not been able to pull the boat out of the water yet so two weeks of saltwater exposure inside the lower unit is where I am at.Although nobody has looked inside the unit, the marina mechanic is adamant that all the bearings have been ruined even after exposure to salt for just this short period of time and rusting on bearing surfaces may have occured and would be a "down the road" problem once it has started. Although I want to work with the marina mechanic ,who is trying to help keep my costs down while fixing it his way, I am a little @ indifference since there is only 120 hrs on my outboard since new and no exterior damage to the lower unit can be seen other than the propeller shaft sheared right @ the first lower unit housing bearing surface.

 

[rodbolt]

Re: Amount of Time for Lower Unit Repair

without air exposure its amazing how long it can sit with no damage<br /> were it mine I would immediatly dissasemble the case upon removal and find a different mocaneic.<br /> seems yours is a parts changer and not a tech. I did one some years back,03, that had sat on the trailer with water,no oil, in the case from july of 02 to june of 03, only thing it lost was the lower driveshaft, drive shaft thrust bearing and the drive shaft upper bearing. nothing else rusted or pitted due to lack of O2.<br /> so find a real tech or stand by for an expensive repair.<br /> saltwater expose by and of itself wont hurt anything. if its not pitted when torn down,cleaned and inspected it wont pit later if oiled and cleaned. most of the torrington bearings are cheap as long as the bearing thrust surfaces are not pitted. that lower is about the cheapest and easiest unit on the market to rebuild. parts are readily avalible at napa if you wish. I do reccomend BRP seals though. other than shimming the pinion the average idiot that has a 5th grade reading comprehension and some tools can rebuild one. find a real tech and save yourself some headache. only special tools needed that are really mandatory are the drive shaft holding tool and the tru-arc pliers if your unit uses 4 bolts to retain the carrier. ifr yours uses a two bolt carrier its even easier. the rest of the tools are easily made or purchased, a torqure wrench and some seal extractors/installers. if the wifey aint looking hot soapy water in the kitchen sink can be used to clean the case and the parts. make sure they get plenty hot and then blow on them with a hair dyrer and watch the water disapear. then oil the parts and inspect them for pitting or other corrosion damage.

 

[newport]

Re: Amount of Time for Lower Unit Repair

Thanks Rodbolt for the advice. The more I think of it, I am going to pull the boat out of the water next week for the season ( only another month and 1/2 left up here in MA for boating anyway)and work the repair from my home site. A real outboard tech has already been identified to me for $40.00/hour(afterhours)so this will be the way I'll go and get away from the marina. The marina mechanic has been very supportive and reasonable to me in the past ,but his replacement desire vice repair is too costly for me now and with your and others saying it shouldn't require replacement (plus only 120hrs on the lower unit since new!!!)that's the best step to take. Thanks Again.