New old Power of Tower 6 cal 90HP

[Medimarc]

Hi folks,

I'm Marc from Hamburg/Germany and I just made myself a X-Mas gift by purchasing a Hellwig Elektra boat with 90 HP Mercury 6 cyl. The motor was running last time 1 1/2 years ago so I should provide him a proper overhaul. However, I've got some trouble finding the correct parts list because the serial no (9177674) does not match any of the usual resources. Are there different numbers provided for Europe/Germany or why can't I solve that puzzle?

Next question: Where should I start apart from changing spark plugs / gear oil and so on? Anything special I should know about this particular engine type (I already read a lot about the famous inline 6)?

Thanks a lot in advance!

Merry Christmas to all

Marc

 

[Chris1956]

Marc, You will need to figure out the year of the motor. I expect it will be late 1980s model. Not sure if Germany has it's own serial number set, or if it is from Belgium, which does have unique serial numbers.

Spark plugs are fine to change, but they last many years before wearing out. If the center electrode is flat across (versus rounded), it is probably fine. Definitely change the gear oil and grease the swivel and tilt grease fittings. Grease the steering as well.

The other part of the motor that is prone to need attention is the carbs. If the motor idles well, they are probably fine. If not they need to be cleaned and rebuilt.

It also makes sense to rebuild the waterpump. It is not hard, but if you have never done it, someone should help you or you need a service manual.

Best of luck with it. The IL6 motors were good motors, with lots of mid-range power and good top speed.

 

[Medimarc]

Hi Chris,

Many thanks for your reply. Next time I'm at the boat, I'm gonna check the year. Is there any source you know for service manuals or handbook showing how to disassemble the water pump or where to grease? Which kinda oil would you suggest for the gear? I always dreamed finding such a motor and I was pretty surprised when I came across this one

 

[racerone]

The 9177 numbers appear to be a 1978 model.---A picture helps identify.-----Many videos ( some better than others ) can be found on utube.------Changing the pump impeller is easy to do.---Just a few nuts and bolts type work.----Ask before using a hammer on outboard motors.

 

[Chris1956]

A 1978 Merc Inline 6 will have battery powered CDI ignition and a distributor. A late 1979 or newer motor will have six coils and no distributor. See what you have.

Any gear oil recommended for mechanical shift marine motors is fine. The best service manual will probably only be had at a Mercury dealer or factory outlet for manuals. There are good some online manuals, but the sites are real slow.

 

[merc850]

Well I would do a compression check;120+ psi; then move on to changing the gear lube - check for milky appearance and/or water, (undo the lower and air vent screws in the gearcase, let it drain then fill from the bottom up with engine in vertical position) refill with Marine gear lube only.
After that you should change the impeller (Nr. 28 on diagram) and you'll probably need the full kit that includes gaskets 22 + 24.