Impeller replacement gone wrong – Suzuki DT 9.9C 1994

[TLagerback]

My parents asked me to have a look at their Suzuki DT 9.9C from 1994 to see if there was any maintenance work needed. The anode was completely gone and I asked them about when the impeller was changed the last time. It appears it has not been changed ever! That´s 26 year by now…

I have experience with inboard diesel engines and are quite handy (sailed across the Atlantic and have owned sailboats for more than half of my life) but my experience with outboard engines is scarce. However, I decided to drop the lower unit and replace the impeller. Removed the bolts from the lower unit, it opened a couple of mm by itself and by some light force it opened to about 10-15mm. Then it felt really stuck, probably the 26 years of corrosion. I searched the internet for advice and accordingly applied some more force. It worked and the unit started to drop. After another 10-15mm I realised that the drive shaft did not follow the lower unit but rather was pulled out of the lower unit. No turning back I thought and soon the lower unit was dropped and the drive shaft stuck in the engine…. (see pictures)

So now what? How to remove the drive shaft from the engine? Is the lower unit wasted now or can I reinstall the drive shaft in it? If so, how? I am glad for all advice and want to have a go before I might leave the engine to a shop (might not be worth it due to the age of the engine).

Yours sincerely,
Tobias

 

[BruceK]

The book of words found here has the following to say:

Once a season the lower unit needs to be dropped and lubrication on the
driveshaft splines renewed. An extreme pressure moly lube is applied directly
to the splines. Seals or an 0-ring are used around the driveshaft to retain the
lubrication and keep the water and exhaust from the splined joint area. This
is a mandatory service to keep the splines from rusting together. Exhaust
pressure and water are both present at the joint seal. If a seal failure occurs,
water washes the lubricant from the splines and rusting will occur. The rust
can be so severe that the two shafts will be rusted together. This will first be
known there is an attempt to drop the lower unit. it will not separate from the
powerhead.
If rust has seized the joint, the drive shaft will have to be cut with a saw or
cutting torch. Some driveshafts use stainless steel and others a good grade
of steel. The best preventive service is not to let it happen. Service the spline
joint each season along with a water pump impeller replacement. When
water has been found in the lower unit oil, the unit should be pressure tested
with air to 1 6-18 psi and the submerged under water or sprayed with a
mixture of soapy water. Bubbles will come out of the areas that are leaking.
Also, the unit should be subjected to 3-5 inches of vacuum. This will test the
seals in the other direction. The pressure vacuum should hold for a few
minutes.
After the shafts and housings are cleaned and inspected, special attention
should be paid to the area's that are leaking. it is common for grit in the
water to wear thew shafts at the seal contact points or for corrosion to eat
away at the housing.
If the gearshift jumps out of gear, check the detent balls, spring, clutch
dog, gears and shifter.
If the gearshift won't shift, check the pivot pin, lever or cable adjustment,
shift rod connection, gearcase components and driveshaft. Replace any
damaged or worn parts.
If the gearcase is seized, check the gearcase for lubricant. If lubricant is
present, drain and disassemble the gearcase. Inspect all components for
damage or corrosion. Replace oroken or corroded components. Check for a
distorted gearcase housing.

 

[[2068]]

Dammit, that's not good.

Take a look at the parts diagrams:
1994 Suzuki DT9.9CESR Parts | OEM Outboard Parts | Boats.net

Removing the driveshaft housing should give you better access to the stuck shaft.

Then look at the "transmission" diagrams ... the shaft is meant to be secured in the lower unit with a circlip / snap ring.

So a lot of bits might end up coming apart.

If nothing else, it will be an interesting exercise on how an outboard comes apart and goes together.