lower unit issues

[capnfred]

This is an early 90's vintage 5hp 2 stroke, the engine was laid up for some time with no oil in the lower unit, unfortunately it appears to have had water in it so you can imagine the mess. I am in the process of rebuilding it but have a question before I go further. To this point I have removed the water pump, and the front cover of the gear case.. I want to remove the propeller shaft and gears but they appear to be held in place by the shift cam....which is currently fast in the housing....

1. Is my assumption that the shift cam is what is holding my propeller shaft into the housing...

2. My plan is soak the housing and shift cam with pb blaster, let it sit for a few days.. then try to remove the cam, my concern of course is to not break anything in the process... using the parts drawings it appears that the shift rod is connected to the cam via a roll pin, so I do not want to put too much pressure on the joint.

3. The propeller shaft moves freely under what appears to be spring tension, but will not come out of the gear casing....

any suggestions or ideas are appreciated....

thanks

capn

 

[pvanv]

Re: lower unit issues

What is your make/model/serial?

 

[capnfred]

Re: lower unit issues

Its a Nissan 5hp, not sure of the serial number...no nameplate data.....I am assuming it is a NS5, have been soaking the shift cam in pb for the past couple of days.....still no go..... guess the next step is the judicious application of heat and pressure.... any advice before I proceed is appreciated...

thanks


capn

 

[pvanv]

Re: lower unit issues

Is your water bump on the prop shaft or on the driveshaft? If the latter, it's probably a 5B.
The prop housing, shaft, rear gear, clutch dog, push rod, et al, all dumps out the back of a 5B as a single unit, leaving the cam, etc, behind.

 

[capnfred]

Re: lower unit issues

water pump is on the drive shaft.....at least it was,, all that is off... the hub is gone...the prop shaft etc will not come out... it moves in and out... but something is holding it in place....since the shift rod and cam will not move I am assuming that that is what is holding the shaft in place....there does not seem to be anything else in the way.....any other advice is appreciated...

voila, got the shaft out, as you can guess the propeller shaft housing came out in many bits and pieces, the outer ring (where the o-ring seats) was holding everything in.... once I got it out everything but the rear bearing came out.... so now I am soaking the gearcase in blaster hoping to get the cam freed and to loosen the bearing which I am replacing,,,,,, sooo the next issue what to do do get the bearing out.... is there a special tool that a tohatsu mechanic would have, in lieu of that I am thinking heating the gearcase and tapping the case on a block of wood hoping the bearing will fall out..... how does that sound....again looking for advice... thanks for the help so far... got me thinking along the right lines once I knew the cam was not the issue.... I now see how it works....


capn

 

[pvanv]

Re: lower unit issues

Not to rain on your parade, but this job may be approaching the "uneconomical to repair" stage. If the gears are rusty and pitted, you will need a new set. At a minimum, you will need to replace 369S601011 HOUSING, PROPELLER SHAFT $28.52, and the 345650150M O-RING $2.53 as well as 960106004M BEARING $9.27.

The "factory method" to remove the forward bearing is with a long-arm gear puller... But, the "shade tree mechanic method" is to pack the shaft opening in the bearing fully with grease (probably using an injector needle type attachment for your grease gun), no voids in the grease pack, and then inserting the shaft just barely to the edge of the bearing, and striking it with a mallet. The hydraulic pressure should push the bearing out. Done all the time with clutch pilot bearings on autos. Heating the housing enough for the bearing to drop out may damage/warp the housing.

Odds are you will find that most of the shaft parts, cam bushing and o-rings, clutch dog, gears, push rod, spring, spring holder, etc., are also trash from corrosion. And the housing may or may not be cracked from freezing water.

I'd be on the lookout for a used 5B with a blown powerhead, and then do a mix-and-match of the donor motors until you have enough bits for a complete unit.

 

[capnfred]

Re: lower unit issues

surprisingly the stuff inside, gears, shaft, clutch etc were in great shape.... not corrosion anywhere, no pitting etc..... I have the neat little puller, but unfortunately with the cam where it is I cannot get it in... the hydraulic method is a new one for me..... thanks... have never had to do something like that so I am always interested in learning new tricks when it comes to wrenching.....never to old to learn..... as for the cost effectiveness.... right now I am rite at $100.00 for the parts.....the most expensive being the castings....as for cracked from freezing, don't see much of that in SW Fla......LOL....just hate to see such a sweet engine abused this way..... thanks again..

capn