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Need Info on 40HP Mariner

T

tomtwh

New member
"I have just acquired a Marine

"I have just acquired a Mariner 40 HP on a '69 14'fiberglass boat. Labeled as Mariner }40E, SN is 6E9 S103006. I'd sure like to know what year it is, and what maintainance/oil mix to use. I changed the LU grease, and ran it in a tank prior to purchase and the impeller seems OK as indicater "pees" OK. Took it out today and it ran fine, electric start & choke work. I hope I've got a winner...any comments/suggestions would be appreciated...Thanks"
 
"That motor was one of the las

"That motor was one of the last ones off the line in 1984.

It is a Yamaha built (for Merc), "C" model Mariner.

It's is 100% Yamaha, based on their own model 40FE which ended production about the time yours was being built.

They did however, continue to produce the 40C for Merc up until 1994, so parts support is still fair from any Mercury dealer.

This was by far the most popular and prolific Yami/Mariner ever on the market.

It was exceptionally well built and designed, but was based entirely on late 70's technology, so it "mechanically" older than the date of production. That however, does not detract from the performance of the motor itself.

If maintained anually it is a well performing, very durable motor.

You can mix her at 50:1 with regular unleaded and TCW3 rated Marine 2 stroke outboard oil."
 
"Hi Graham,
Thanks so much fo

"Hi Graham,
Thanks so much for the info, I've been running a bit rich (32:1), will back off in the future to 50:1 oil mix. Other than smoking & fouling plugs, is there any harm in running too rich an oil mix?

Other than stabalizing the feul & running it dry for winter storage, hitting grease fittings & changing the LU grease, is there anything else necessary maintainance wise for Freshwater use?
Thanks - Tom"
 
"Absolutely no mechanical issu

"Absolutely no mechanical issue running oil rich, but as you note, can foul plugs and could also carbon/cootie up the cylinders which then could lead to some performance issues.

When you lay it up in addition to what you note, pick up some "fogging oil" or even WD-40. Remove the sparkplugs and give the cylinders a spray - you can also "fog" everything under the hood - ya, it's a bit of a mess, but really protects the wires from moisture and the hoses from cracking. You can also give a shot of fogging oil to the carb - right down the throat, that will help keep moisture and other cooties out of the intake and the reeds.

When you are getting ready to bring the motor back (or to clean up those oil/carbon issues), grab yourself a can of Merc "PowerTune", it's a great product and only costs 5 bucks - and just follow the directions on the can - cleans out carbon, foggin' oil, normal oil, cooties and whatever else may have crawled in the system during storage. If you get something resembling chocolate milkshake coming out the exhaust, you know its working
"
 
"Graham, Thanks so much for th

"Graham, Thanks so much for the info...we're in good shape, and have a higher confidence level...
Keep up the great work...Tom"
 
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