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Just started working on my $50 Tomahawk Speeditwin today.
The flywheel would move back and forth about 1/8th turn.
Pulled the spark plugs and observed that the pistons were actually
moving. The lower unit dropped off without too much trouble,
and then power head turned over nicely, and with nice compression.
No rings were even stuck. Off to a good start.
Then noted that the gear case cap was broken and nothing turned.
Had to monkey a while getting the cap and prop shaft off.
Only problem is, only half the prop shaft came out. It’s snapped off
right at the shear pin. 🙁
The rest of the broken prop shaft and gear wiggles all about and up
and down about 1/2″, but wont come out of the gear case.
The drive shaft will not turn. Not sure if the drive shaft has a ball bearing,
but if so, it’s probably rusted solid like the prop shaft bearing.
Any ideas on what could be keeping the rest of the prop shaft
and gear from coming out of the case, or how to proceed?
Thanks!
Prepare to be boarded!
You have one of the last models built. As you found out, most outboards die of neglect. This is the parts book . . .
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As you can see, the prop shaft thrust bearing and pinion bearing are rollers. You can drill a hole in the plug in front of the prop shaft to drive it out, and then tap the hole for a pipe plug. Dad built out the front of his to a knife edge, but he was a bug on speed.
I got the remaining stuck and broken piece of the prop shaft out of the gear
case today. I started to drill out the plug in the nose cone as Garry suggested,
to pound the shaft out of the rusty bearing, but thought I’d drill and tap a
hole in the plug for my slide hammer. I clamped the broken prop shaft
in the vice while I used the slide hammer. The plug did not want to move,
even with heat, but after a bit all the hammering pulled the remaining
prop shaft guts loose. The drive shaft was frozen, as well as the drive
gear on it’s end. Lots of lube and a pipe wrench got the drive shaft
finally turning. I found a punch that would fit into the gear case drain
hole, and I was able to pound “up” on the driveshaft, knocking it
out of the gear.
Now, the only problem is that the drive shafts tapered roller bearing’s race
wont come out. There’s no way to knock the race out from top side,
and no obvious way to dislodge it from the gear case that I see.
The race appears to be sitting on brass shim stock. I tried prying
with a screw driver but that was futile.
Any ideas??
Is the race suppose to be a loose fit, or press fit?
The prop shaft gear may be okay for Sunday use, but
I need to get the broken prop shaft out of it. The inboard
bearing removed easy from the shaft.
Anyone have bearing numbers wrote down for the 6039 Speeditwins?
I’ve only been able to read the number on one bearing so far……
I think! Hopefully they’re still available.
Also, the impeller is stuck on the drive shaft. It appears
to just ride on the drive shaft spline, as I see no pins
or other types of keepers. Is this correct?
I’ve seen no parts I need on EBay yet, so my have to try an
ad. Thanks!
Prepare to be boarded!
I was able to get all the guts apart from the lower unit today, other than
the impeller that seems well attached to the drive shaft. It’s not critical
that it comes off anyway, so I’ll leave well enough alone before I break it.I tried ice cubes in the gear case to shrink the drive shaft bearing race.
I let the ice sit for about an hour, and kept adding. Then got the torch
out and heated it up nice. Slapped the skeg down on the bench a
bunch of times, and rapped on the housing hear the race with a wood
mallet. …….. and…… Nothing happened!
Therefore, I devised a tool to get at the hidden side of the race.
A piece of bent, sharpened metal strap, that hooked the back of the race (barely).
I helpd pressure on the strap tool with a big screw driver as I hammered
on the tool via the drive shaft bore, with a tire iron. I alternated doing this
and prying on the visible side of the race with a screw driver. Pretty
soon it popped out!Now, the bigger challenge perhaps……. finding parts.
The drive shaft tapered roller bearing and the prop shaft tapered roller bearing
both use the same race / cup, but different bearings. Those I’ve found
available so far. I’m not finding the two cones / bearings, but it may be
I have the numbers wrong. Very hard to ready the numbers on them from
all the rust and corrosion.The two said cups / races are 05185
The Drive Shaft cone /bearing looks like 05079 (iffy on the middle 0 and the 9)
The Prop Shaft cone / bearing looks like 05056
The Drive Shaft ball bearing looks like ND 3205 (iffy on the 3)If anyone has bearing numbers for the 6039 Speeditwins in their database,
I’d be grateful to know what’s correct.I suppose it’s theoretically possible to make a new prop shaft, I’m not sure I’d
be successful. Were they machined first, then heat treated for hardness?
Prepare to be boarded!
I’ve gone through the same exercise, although my model is earlier (6026) and there was lots of grease in the lower unit and nothing was too stuck. That said, I have yet to remove the cups. As for the bearings (cones & cups), I determined that the drive shaft on mine is 3/4″ dia. The forward end of the prop shaft is also 3/4″. In old bearing speak, that is a 05075 cone. The corresponding cup is 05185. My prop shaft is smaller on the prop end. It’s .66″ therefore the corresponding bearing cone 05066. It also uses the 05185 cup. Imperial taper bearings use a common numbering system so a “05075 cone is the same number in Timken, National, SKF. You can look up bearing dimensions in the CAD drawings available online from Timken. There are a few different 05185 variations, depending on if the outer edge of the cup is chamfered and if so, how much. Therefore it could be an 05185S or other. I am not a bearing expert – this is from my research. I believe your motor is the same from the comparisons I’ve made (by part number) while trying to find my own parts. Your prop shaft is probably straight and therefore 3/4”. If so, you need the 05075 not the 05066.
I hope this is helpful.
Thanks for the “helpful” information on bearings. It sounds like my new
Speeditwin has bigger shafts than yours.The major part of the prop shaft (which the ball bearing rides) is 25 mm, .984, or 63/64″ inch
The small end of the prop shaft that the tapered roller bearing goes is 15.5 mm, or 669″
My drive shaft is .785″
From researching, I believe the correct prop shaft ball bearing I need is a 6205.
The two tapered roller bearing cups are 05185
I still need to do more research on the two tapered roller bearing cones. I’m not sure
how to measure them to match up online specs, so I’ll have to study those CAD drawings.You say that a 05075 cone translates into fitting a 3/4″ shaft. Is the 75 on the end of
the number telling me this, that “75” = .750″
If so, what would one conclude the numbers to be for a .669″ (or 15.5mm) shaft be?
050 _ _ ?Thanks again for the help!
Prepare to be boarded!
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