Mercury Inline 6 115 HP

Bry21317

Chief Petty Officer
Joined
Apr 9, 2002
Messages
552
I have a friend who had purchased a boat for 1100. The trailer and boat are in good condition, but the motor has some problems.<br /><br />The boat is around a late 70s or early 80s, same with the Mercury 115. When I first worked on it for him, it wouldn't run. Finally I was able to get it to run, then we took it to the lake, and it wasn't spitting any water. So I made him turn it off, we trolled back to the dock, not far out at all. Took it back, and I took the lower unit off. I went to pull the Impellar off and it was so full of sand, and was completely eaten off, there were no fins left on it, just the round cylinder. We got all the sand out, and put it back together with a new one.<br /><br />Fired it back up with the ears,well now it spits water out of around the Spark plugs, I have never seen anything like this before. The water also seems to come out of the pee hole. Then we did a compression test on the cylinders all cylinders are dead on about 158, except the #1 cylinder, it has 0 Pressure. It seems to have some tiny bits and pieces of metal, that ended up sticking to the bottom of that spark plug, after it was run the last time. <br /><br />Does anyone have any ideas on this, or does it seem that this engine should just be scrapped? Everything else on the engine is in perfect working order, as the guy at the shop told him.<br /><br />We have a friend who is a Car\Motorcycle Mechanic, who said he would look at tearing it apart, to see if it is worth trying to fix, or if he can, in the next week or so. <br /><br />Thanks,<br />Bryan
 

12Footer

Fleet Admiral
Joined
Mar 25, 2001
Messages
8,217
Re: Mercury Inline 6 115 HP

Bad news,I'm affraid. The metal on the spark plugs and 0PSI compression on #1, mean the piston has a hole in it. And given the age of this motor, it would not be cost-effective. It can be rebuilt, but you'll have 1100 to 2000 bucks in it by the time you are done. They were dynomite engines in thier day.<br />They may have read "115" on the cowling, but I firmly believe they were under-rated HP-wise.<br />But if it were mine, I'd carefully dissassemble her,clean-up and box al good parts, and post them on ebay. By the time my last auction has been won, I would have enough for a sizeable down payment on a brand new engine, or enough to maybee buy a used engine outright.<br />OR, find another old "tower of power"inline 6,and keep the old one for parts.
 

skier

Petty Officer 1st Class
Joined
Jan 31, 2002
Messages
336
Re: Mercury Inline 6 115 HP

12Footer, Mercury has always under-rated their motors, it's a given. My 79 140 almost kept up with a V-6 150 Black Max. He could only crawl away from me. I loved the look on his face as he tried to find more travel in his throttle.<br /><br />Craig
 

Bry21317

Chief Petty Officer
Joined
Apr 9, 2002
Messages
552
Re: Mercury Inline 6 115 HP

Chum Slick,<br />Once he decides what he is going to do with the engine, which may be about 3 weeks he is saying before he wants to start tearing it down, then I will let you know for sure.<br /><br />Thanks,<br />Bryan Cox
 
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