A large number of mid 60s to the mid 70's houseboats were equipped with DANA and CHRYSLER DRIVE 90 outdrives. Most installations utilized 225 HP 318 engines which were almost bullet proof. These were some of the best out drives ever produced.
The only problem is that the expertise needed to work on these units has retired or died.
If you are considering purchase of a boat with one of these installations you should obtain the manual to furnish to your service person prior to purchase of the boat.
The biggest difference, in these outdrives vs Mercruiser, is in the incorporation of an automotive clutch, hydraulically applied by a power steering pump. This setup provides smooth shifts with no clunk. Depending on the year, this involves a mechanical or solenoid valve to operate the clutch. Proper operation of these drives require that valve operation be set up "by the book".
FAQ's regarding these drives.
What brand do I have:
Rounded upper with fin with hole DANA
Rounded upper with a chunk no hole DANA
Flat upper CHRYSLER DRIVE 90 and replacement housings.
What model do I have:
Straight output shaft takes outdrive _style_ props, SHIFT IN OUTDRIVE - MODEL 80
As above WITHOUT SHIFT IN OUTDRIVE - MODEL 81
Tapered output shaft takes inboard _style_ prop, SHIFT IN OUTDRIVE - MODEL 90
As above WITHOUT SHIFT IN OUTDRIVE - MODEL 91
All the CHRYSLER units that I've seen were model 80 internal configuration.
In addition Model 81/91 came in 2 configurations:
R/R L/L and R/L L/R (engine/ outdrive) rotations
The model 81/91 used regular marine transmissions inside the engine compartment. Usually Warner Velvet Drives. If you have one of these units you are really in "TALL COTTON"
There were 2 gear ratios available but unless you have a 360 or 440 engine its not an issue.
THE INTERNAL DIMENSIONS OF THESE CASES IS IDENTICAL AND ANY PARTS CONFIGURATION WILL FIT IN ANY CASE.
Clutch pump oil pressure. 300 psi +/- 25 psi. If you get a junk yard or GM replacement pump swap out the reservoir which has the heat exchanger built in and also the relief valve which has the proper spring to provide the 300 psi. Same rules apply if your boat was equipped with the Chrysler pump (rare)
They also built a model 60 but I have never seen one.
They built a few units where the bellows had a protector over it. I have only seen 2 of these.
These units were some of the toughest outdrives ever built. The reason they shift so smooth is the hydraulic clutch mechanism on the engine. If this is maintained properly these units will last forever.
Filling with oil. These units tend to get air locked and can fool you into thinking they are full. Operate them in forward and reverse and check. These units hold 8 quarts of oil. If you have the extended length version they hold 9 1/2. Remove a cap screw out of the top of the shift lever cover when oil comes out you have the proper level. DON'T forget to put it back. Do not overfill because expansion can force out the top seal.
Hard shifting or clunking when shifting. hydraulic clutch not working - clutch plate stuck to flywheel.
Won't go into Forward/Reverse. Springs or cotter pins in intermediate shift _link_ missing or broken. (sometimes called shift assist _link_ or shift booster) Note: make sure you use stainless cotters and springs for replacements.
No drive. splines stripped off primary shaft on clutch plate end. Always use spline grease or moly when installing the outdrive.
Rattling when turning. U joint shot. Look for same size Chevy joint, a lot cheaper.
Won't stay in gear or skips. Adjustment if your lucky, if your not Nubs are worn on clutch dog and gears.
These parts can be tig welded up and reground. Use something that comes out to about 50 Rockwell hardness and grind to a 3 degree positive rake. Look in the yellow pages for TOOL AND DIE REPAIR SHOPS to do the welding and CUTTER GRINDER SERVICE to do the grinding. Show them this note.
Marysville Marine in Marysville Michigan is a good source for help on these units as is Marine Parts.com The other Marysville Marine locations don't know these units exist.
Marine Parts.com is also a source for parts and manuals
If you get in trouble I have installation information with adjustment dimensions. However you really need to buy a manual.