Inline 6 newbie

Hi, i have been an omc man all my life, but could not resist buying today a clean original 1981 hydrostream viper, bruiser (blue and black metalflake) with a clean old freshwater 1973 115 inline Merc. It has a 14 x24 Chopper, and i love it. I have never run Mercs before, so i need to know; THIS HAS NOT BEEN STARTED SINCE LAST YEAR, AND IT RAN GREAT THEN, AND HAD GREAT COMPRESSION. The boat was put away last September with Sta-bil, and not fired since. Do i need to drain any fuel on these, or can i simply drain the fuel in the tank and hose, mix some seafoam with the premix, and let it run on earmuffs at a fast idle for 30 minutes to get the carbs moving again?

Any thoughts on octane for this? 40:1 or 50:1?

If i need to do something else, please tell me AND I WOULD APPRECIATE SOME SPECIFICS LIKE PICTURES AND DETAILS ON WHAT TO DO. I have never worked on a Merc, only driven a few.

Thanks a lot.

Ronny
410 394 9000

Use a good oil mixed 50:1. You might get lucky on those carbs, but I've seen too many old motors that needed fuel line and F P diaphram replacement. The ethanol in the gas can eat 'em up. The impeller will also need changing or it could toss vanes into the power head.

Jeff

Unless the entire engine side harness has been replaced, you will most likely find wires suffering from "cancer" on that motor. Use caution when handling the harness while cleaning carbs or any other maintenance. I'm always nervous about servicing those old mercs. No one wants to have to start replacing a stator or harness while doing a routine carb cleaning. The earlier suggestion about replacing the impeller is good advice. Just cause it pumps water, doesn't mean it's not about to start throwing vanes. Get a new impeller and you'll know it's good.

I got her running. Sounds MEAN. I like it. I know i need to get a factory service manual, until i do, anybody got a step by step on how to change the waterpump? Assuming it is similar to an omc, need to disconnect shift linkage, and remove a few bolts. Pictures and step by step would be great if anyone feels like it,

thnaks

ronny jetmore

You have a PM

You do not need to disconnect the linkage. Put the gear shift into forward gear and then remove the bolts and nuts just like on your omc. The L/U will come off and the W/P will be accessible from there.

Youtube has plenty of step by step videos on this topic. I'd look there and good luck!