Giving a Bezoat a Second Chance

[deeougee]

Servicing the gearcase is not complicated if you have the right tools, information and attitude. Contouring the foot is not hard either. There are min-max dimensions in the APBA Technical Manual for racing, start there. You can then decide how far you want to go with the foot. If you go all out, make the templates you need and get some radius gauges. You can use some power tools, hand tools, sand paper and polishing materials to bring the foot up to spec. Make sure the skeg is straight with the centreline of the foot, there are several ways to check this (helps with handling). If you need to add material to an area, you can do that also, several ways to do it. Big thing with the gears, use some low or medium loctite on the nuts holding the gears. Been many a gear set / gear foot ruined because one of the nuts backed off. Good Luck with your project, ask questions if you are stuck on something. Lots of people out there that can help you out.

[ZUL8TR]

Good motto my first time apart was a learner.

From my experience before and after the gear case shaping there is better water pickup to run at 1/2" prop shaft below bottom but that is also a function of boat and prop and tuck. As far as speed increase not really noticeable since so many variables that changed before and after with temp, water condition, wind, humidity, set up, etc. Would need all things the same and switch within a short time the non to shaped gear case and accurate speed measurements and there would still be uncontrolled variables. Others have different experiences.

[Albert]

Our unofficial family motto is “everything is easy once you know it”

Spoke to the previous owner who I consider trustworthy. This gear was all run last year before the rod bearing let go. I’ll check for play in the bearings and make a call.

The real question is how much is there to be gained in having the nose cone shaped? Is there 1-2mph there, or is it done to encourage better pick up at the water inlet?

[ZUL8TR]

Hmm, maybe I’ll take it apart for inspection purposes (famous last words of every failed project).
Really it doesn’t look too complex. The only thing on that list that doesn’t sound very diy friendly is the shaping of the nose cone.

That gear case has already been apart because the prop shaft has the shear pin hole close to the nut and it is a 9/16" diameter shaft.

Before any pull apart check the prop shaft for any side to side wiggle and any in out slack, that will cause water to enter at the outer seal with prop running with variable loading. All signs of worn dbl ball bearings on the prop shaft those bearings are pressed off and new pressed on. There is also a full complement roller bearing pressed in the cone that supports the prop shaft close to the propeller. The race for that is pressed on the prop shaft. Any side slack could also be this roller and/or race is worn. The race is probably hard to get. Also check the gear lash by feel an experience thing gear case needs to be off the tower to check. Spec is 0.004"

If you want to take apart the gear case here is what I do. Helpful to have the parts manual that shows the exploded view of the innards? Note the outer cone is righty loosy and a special tool is needed to grab the 4 slots on the cone to prevent damage. If to spec that cone is on with 60 ft-lbs and best removed while gear case is on tower. Once loose the cone, prop shaft with prop gear and dbl ball bearings come out as a unit. Be careful of the shims on a ledge inside the gear case that the cone piece is tightened against these control gear lash. I use heat (200 - 250F 15 minutes no damage) in a small toaster oven and the prop shaft falls out with the dbl ball bearings that are pressed on the shaft, goes back easy with heat. Manual says tap out prop shaft, didn't work for me. There is another shim inside the cone piece (not shown in parts manual ?) that the ball bearings are bearing against and is used to adjust bearing height to be right level to the inner surface of the cone where a large flat spacer is. The new seal is pressed in at the outer part of the cone. Reinstall of cone assembly needs to be carefully done to prevent damage to the shims.

There are bearings and seals on the drive shaft that need. Check top ball bearing for any side to side play. The seal is removed with the gear case off the tower and a long poker is used down the tower to pop out the seal. Tap in new seal into machined hole at tower bottom.

The seals are prop shaft, drive shaft and big O ring at cone threads and there is a gasket on top of the gear case to seal at the tower.

Might want to send it off to an expert, since might look simple but_______ ?

Had my gear case shaped by Tom Cronk local to me but last I heard he no longer does them.

[DeanFHobart]

That is correct....someone with experience needs to do the smoothing and shaping.

[Albert]

Hmm, maybe I’ll take it apart for inspection purposes (famous last words of every failed project).
Really it doesn’t look too complex. The only thing on that list that doesn’t sound very diy friendly is the shaping of the nose cone.

[DeanFHobart]

Dean,
What exactly is involved in a service of one of these ? Just a bearing replacement and setting gear lash?

All of that + seals... the prop shaft threads look rusty... that might suggest there may be bad news on the inside... which might require new gears. Also, the case outside may need shaping and smoothing... the picture doesn’t show if the ‘bulb’ on the bottom of the keg is there or not... if it is there it would need to be removed. Ron Thomas will know what to do.

All of the dimensions need to be checked for legality.... per the spec sheet.

[Albert]

Dean,
What exactly is involved in a service of one of these ? Just a bearing replacement and setting gear lash?

[DeanFHobart]

I would suggest having the gear case serviced by someone who knows these gear cases. I might suggest The Foot Doctor... Ron Thomas.

[Albert]

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What does the lower unit look like???? PICTURES

It looks like a lower unit...anything special I should look for ?

[Tom Cronk]

What does the lower unit look like???? PICTURES

[Albert]

There you have it folks, looks the the project it intensifying.

[Carruthers]

As for the staples it will likely be impossible to pull out so probably just countersink and fill and as for the bottom I believe the the entire tunnel will need replaced just because of issues at the front 3 feet and back three feet so to replace the whole thing makes sense and it will give a chance to fill in the relief in the back as it is not needed with the current motor height rule

[Albert]

Points cam looked great , cleaned it up as you suggested as found no signs of cracks. Levelled the block as the manual instructed.

[ZUL8TR]

Luc
How did the point cam check out, any sign of a crack at the key way? When I do pull apart on the Yamato and back together I check the cooling system for any leaks using a hose nozzle at the tower plug under pressure and block the 2 exhaust snoot water intake holes with strong tape. The 80 is susceptible to leaking under pressure at head bolt nuts with the 18mm head because the head bolt studs are right in the coolant in the hollowed out head where the studs pass thru. Maybe the 14mm head is different? They changed the head design in the 102 and later to provide a positive seal with studs passing thru cast aluminum towers that pres against the gasket when torqued. The head can also leak at the alum gasket.

In the tower get the megaphone level for good seal to powerhead I noted in post #28

Looks like going well

Pete