1977 Merc 115 Year?, Charging?, Pulling to right?

kenneymc

Seaman Apprentice
Joined
Mar 27, 2004
Messages
41
Hi, Let me start off with saying this is my first boat and took it out for the first time yesterday. Runs great but have a few questions.<br /><br />1. I was told by previous owner it was a 1977, but I am not sure. Serial number is 4396353, on cover it says it is an 1150 / 115hp. 6 cylinder 2 stroke. Any help?<br /><br />2. After 3 to 4 hours of running it off and on yesterday, it would no longer turn over and crank. I put a new battery on it and it cranked fine. So somehow the battery went dead. I had just charged it real well 2 nights before. It is a non marine battery and I am fairly certain it is good, but not totally sure. A friend pulled the negative post off of it while engine was running and it died. He says that the alternator was bad on it and will cause it to do this. I searched this forum and read several threads concerning this subject. I checked the rectifier (what i guessed was the rectifier from other posts, pointed on two ends with three wires attached to it)as was posted in one thread. When going from ground to one of the 2 non "+" terminal it was like 4 ohms or a short. I am guessing this is bad. Where is a good place to buy a rectifier from? Where is the stator and how is it checked if need be. Is there anything else in the charging system? My friend mentioned the alternator being bad, but i don't think it has one like a car does. <br /><br />3. My boat pulls hard to the right when going straight. This is tiresome. One post stated to check the trim tab, but i have no clue where it is or what it looks like. Just above the prop and to the rear of it is a small tab hanging down. Is this it? It is turned off center to the left a little bit. This is when viewed standing at rear of boat facing the motor.
 

Spidybot

Lieutenant Commander
Joined
Apr 4, 2002
Messages
1,734
Re: 1977 Merc 115 Year?, Charging?, Pulling to right?

Model 1150 (115,0) #4310785 - 4567951 is 1976 6 cyl inline.<br /><br />Pulling a battery wire while running is plain 'dumb'! Easiest way to make something suffer.<br /><br />Put a volt- or ampmeter on when the motor runs to know if it is charging. A voltmeter shows yout battery power when motor is shut off and should raise when motor revs. up. Amps will depend on what system is on your motor. A manual (link on this page if you don't have one) will tell how to test this in detail.<br /><br />You have descibed your trim tab, so you've found it :D
 

rickdb1boat

Supreme Mariner
Joined
Jan 23, 2002
Messages
11,195
Re: 1977 Merc 115 Year?, Charging?, Pulling to right?

I don't know too much about those old Merc's, but I can tell you it's a 1976 Model. Unless your battery is defective, it should be able to run all day on a good fully charged battery, even if the charging system isn't working. I'm sure yours isn't working. The stator is under the flywheel, but I wouldn't jump into that right away without further advice from others. You are correct about that being the trim tab. If the boat pulls to the right, move the rear of the trim tab to the right. Sounds like it's facing the wrong direction now. Move it to the straight position first and move the rear in small increments to the right from there if it still pulls. Others will have more info on the charging system..
 

rickdb1boat

Supreme Mariner
Joined
Jan 23, 2002
Messages
11,195
Re: 1977 Merc 115 Year?, Charging?, Pulling to right?

I don't think "Dumb" is the correct way to phrase it, but it is true about pulling the wire when running. It will fry the rectifier in a heartbeat. More than likely, that is the problem. A Factory Manual would be invaluable to you if you plan on doing most of the work on the motor yourself. Here's a link to one:<br /><br /> Factory Manual <br /><br /> Rectifier<br /><br />Look like this?? # 5707<br /><br />
5707.JPG
 

Boatin Bob

Lieutenant Commander
Joined
Sep 24, 2001
Messages
1,858
Re: 1977 Merc 115 Year?, Charging?, Pulling to right?

Another thing to try with pulling to the right would be to trim the motor up a bit while running, you should be able to feel the difference in the wheel while doing this, you maybe running with it all the way in.
 

kenneymc

Seaman Apprentice
Joined
Mar 27, 2004
Messages
41
Re: 1977 Merc 115 Year?, Charging?, Pulling to right?

Thanks Rick and UU. I appreciate the help. The links you gave are excellent, thanks. I will order both of them and see what happens. <br /><br />I intend to get the battery(s) tested somewhere that does it. I think i will purchase a new marine battery as well to use to start the motor. I had 2 other batteries in the boat yesterday as well, but neither of them would turn the motor over, and i had just charged them a week before. They both read 12.4 (or there abouts) volts today on my multi meter.<br /><br />I checked the battery voltage while ago with motor off and it is 12.6 vdc. I then cranked it and let it idle, it read the same 12.5 vdc.
 

kenneymc

Seaman Apprentice
Joined
Mar 27, 2004
Messages
41
Re: 1977 Merc 115 Year?, Charging?, Pulling to right?

Trim did not effect it pulling to the right. I tried it. Thanks though!!
 

SpinnerBait_Nut

Honorary Moderator Emeritus
Joined
Aug 25, 2002
Messages
17,651
Re: 1977 Merc 115 Year?, Charging?, Pulling to right?

Originally posted by kenneymc:<br />Trim did not effect it pulling to the right. I tried it. Thanks though!!
The trim tab is your problem with pulling to right.<br />Turn it where it is straight and see what kind of difference you have.<br />Mine does the same thing, but my prop is so big, a trim tab won't fit in there.
 

kenneymc

Seaman Apprentice
Joined
Mar 27, 2004
Messages
41
Re: 1977 Merc 115 Year?, Charging?, Pulling to right?

Trimming the motor up and down did not help it yesterday pulling to the right. I adjusted the trim tab and centered it up just a few minutes ago (It was off center a bit to the left). I will not know how it effects it pulling to the right until I run her again, which hopefully will be next weekend. Thank You.
 

kenneymc

Seaman Apprentice
Joined
Mar 27, 2004
Messages
41
Re: 1977 Merc 115 Year?, Charging?, Pulling to right?

Well theres part of my problem....had all the batteries tested today that came with the boat when i bought it. ALL of them were BAD and had to be put to rest. So new batteries all around now. <br /><br />Now i just need to get the charging system going (rectifier and manual on it's way). Then get this problem with the "PEE" checked out/fixed (in a seperate post)and all will be good to go.<br /><br />Thanks to all that helped so far. If you have any comments about the water "pee" problem in my other post please add them as I could use all the help I can get.
 

kenneymc

Seaman Apprentice
Joined
Mar 27, 2004
Messages
41
Re: 1977 Merc 115 Year?, Charging?, Pulling to right?

New rectifier arrived today and installed. Charging system now seems to be functioning. These are the various readings I got on my Fluke multimeter. Please tell me if you know if these are normal. It shows that I atleast have some sort of charging going on.<br /><br />Battery w/motor off = 13.33vdc<br /><br />Battery at idle = 14.35vdc / 5.6amps<br /><br />Battery motor idled up some = 14.90vdc / 6amps<br /><br />Readings at rectifier/ motor idling:<br />non + =8.3vac / .7amps<br />other non + = 8.3vac / .7amps<br />+ = 14.35vdc / 5.65 amps
 
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