Mercury tower of power 1115 starter will not crank 1978 I6

[dsay1]

I have a 1978 tower of power 1115 and it may crank once or twice then dies. I jump the the solenoid and starter will turn so I went ahead and changed the solenoid. Tried to start it up and it cranked two times then will not crank anymore. Battery is at 12.5v 85% charged. Anybody have any ideas as to what to check next?

 

[orbanp]

Re: Mercury tower of power 1115 starter will not crank 1978 I6

Chances are that it is your starter that is failing you. Just to be on the safe side, do measure the voltage on the starter when it should be cranking.
If it is your starter, take it apart and see how the brushes and armature looks like. Probably the brushes need to be replaced, and the armature dressed.
The alternative is to have it rebuilt.

Good luck, Peter

 

[dsay1]

Re: Mercury tower of power 1115 starter will not crank 1978 I6

Thanks for the response Peter but it doesn't make sense that the starter will crank if I jump the solenoid. Is there something within the thunderbolt system like a fuse that will cutout if it is getting too hot?

 

[Maxz695]

Re: Mercury tower of power 1115 starter will not crank 1978 I6

The solenoid may be bad. On my 70 HP there is a fuse under the plastic cap that retains the wiring harness pictail. You could check to see if the fuse is good there. Did you try crossing a screwdriver to jum the solenoid? if this works then the solenoid either has a broken feed from the key switch or it,s just shot

 

[Chris1956]

Re: Mercury tower of power 1115 starter will not crank 1978 I6

Normally a 1978 Merc 1150 will not have a fuse anywhere. If you jumper from the battery cable to the small yellow wire and the starter cranks the motor properly, then the ign switch circuit is bad. The quick-disconect plugs can go bad, so check it first.

 

[mr 88]

Re: Mercury tower of power 1115 starter will not crank 1978 I6

The quick-connect pins can be spread out so you have a better contact.Take a small screwdriver and gently insert into the end of the male prong and spread the pin a tad. Try wiggling that connection when someone is turning the key.

Normally a 1978 Merc 1150 will not have a fuse anywhere. If you jumper from the battery cable to the small yellow wire and the starter cranks the motor properly, then the ign switch circuit is bad. The quick-disconect plugs can go bad, so check it first.

 

[dsay1]

Re: Mercury tower of power 1115 starter will not crank 1978 I6

Thanks for the quick response guys, just got home from work and tried to start it up again. It cranked once and did not crank again. I charged the battery up waited an hour while i check the connection on the ignition key switch and it looked good since the last owner just changed it and all the solder looked good. It only cranked one time as well. This is my first boat and I don't know much about outboards. Where is the quick connect pins?

Chris1956 - When you say jumper the battery to the small yellow wire, do you mean, jumping the positive from the battery to the small yellow wire on the solenoid?

 

[mr 88]

Re: Mercury tower of power 1115 starter will not crank 1978 I6

The pins are located in the wiring harness where it plugs into the side of the engine. That connection can be iffy over time and that's why you should double check the contact between the two harness's as well as jiggling it while turning the key to see if that is the issue. Often it will work,then not because of the poor/iffy connection or corroded wires .

 

[dsay1]

Re: Mercury tower of power 1115 starter will not crank 1978 I6

The pins are located in the wiring harness where it plugs into the side of the engine. That connection can be iffy over time and that's why you should double check the contact between the two harness's as well as jiggling it while turning the key to see if that is the issue. Often it will work,then not because of the poor/iffy connection or corroded wires .

Thanks for your response, I see what you are referring to but my model does not have the connector pins on it. The wires goes directly into the engine.

I'm going to go out and buy a new battery next weekend. Maybe the battery is not holding enough cranking amps.

 

[mr 88]

Re: Mercury tower of power 1115 starter will not crank 1978 I6

Something does not sound right.That model should have a harness that plugs into the side of the engine,not hard wired as you stated. Has it been modified? Any pictures ? Before I bought a battery I would use some jumper cables off my car battery and see if that has any bearing on your issue.In most cases if the battery was going it would turn over slower and slower, not crank for a few seconds then just stop cranking when you hit the key again.

 

[Charlie61]

Re: Mercury tower of power 1115 starter will not crank 1978 I6

I had same thing but it was a bad ground.
P.S. I had already paid for a new starter and solenoid, before I find it was only the ground. I look at it this way now I have a spare starter and solenoid!

 

[Will Bark]

Re: Mercury tower of power 1115 starter will not crank 1978 I6

Agree+1, clean the bolts that hold the starter to the engine they are the ground for the starter; no ground, no start. Good luck

 

[Lone Duck]

Re: Mercury tower of power 1115 starter will not crank 1978 I6

Thanks for the response Peter but it doesn't make sense that the starter will crank if I jump the solenoid. Is there something within the thunderbolt system like a fuse that will cutout if it is getting too hot?

How are you jumping the solenoid ? If you it are jumping from the batt + to the starter, you are proving that the starter is good. Same thing if you are jumping across the two large terminals on the solenoid. Your next step should be to take a wire from the hot cable on the solenoid to the yellow wire on the small terminal of the solenoid . If the starter turns over it proves that the circuit from the small red wire on the hot side of the solenoid to your key switch and back through the yellow wire to the small terminal on the solenoid is faulty. (Most likely the switch) If it does not turn over then your problem is the solenoid. I am assuming that you have cleaned both your batt terminals and cable clamps and your batt cables are not broken or corroded inside . My gut feeling is that you have a bad ground or bad batt. Also I wonder what you mean when you said the solder on the switch is good. What solder??

 

[dsay1]

Re: Mercury tower of power 1115 starter will not crank 1978 I6

How are you jumping the solenoid ? If you it are jumping from the batt + to the starter, you are proving that the starter is good. Same thing if you are jumping across the two large terminals on the solenoid. Your next step should be to take a wire from the hot cable on the solenoid to the yellow wire on the small terminal of the solenoid . If the starter turns over it proves that the circuit from the small red wire on the hot side of the solenoid to your key switch and back through the yellow wire to the small terminal on the solenoid is faulty. (Most likely the switch) If it does not turn over then your problem is the solenoid. I am assuming that you have cleaned both your batt terminals and cable clamps and your batt cables are not broken or corroded inside . My gut feeling is that you have a bad ground or bad batt. Also I wonder what you mean when you said the solder on the switch is good. What solder??

I am jumping the the solenoid by way of the two large terminals on the solenoid. The solenoid is new since I thought that was the source of problem and replaced it. All connections to battery and solenoid have been cleaned as well.

I will try jumping the hot wire from the solenoid to the small yellow wire next and clean the connections on the starter as well. Just need to wait until this afternoon since we had a bit of a frost last night.

The previous owner had just replace the ignition key switch on it. He had solder the wires to the ignition terminal pins and they were clean solder connections when I took the control box apart to inspect.

Hope I can get this sorted out and put it away for the winter.

 

[Maxz695]

Re: Mercury tower of power 1115 starter will not crank 1978 I6

It could be the cable between the solenoid and the starter although yours appears to be in good shape. If not sounds like taking the starter apart and a good cleaning is in order be sure to lube the bottom of the shaft as a dry bearing or sleeve will effect the starters performance. I use PB Blaster to coat the armeture with a slght wipe after spraying it. I also spay the cylinder with the magnets after removing the metal and magnet particals. Clean out any debri from the base where the brushes are. Removal may have to be done to do a good job if there is significant crud.. The crud and particals from the armeture, as well as the magnets build up binding the armeture. If this is allowed to continue the magnets can crack causing even move binding. It may also have a broke wire to one of the brushes. The only way to tell open it up and see.

 

[dsay1]

Re: Mercury tower of power 1115 starter will not crank 1978 I6

Ok, after further inspection, I did find the quick connect located inside of the cowl. I took it out and check the pins to find all kinds of gunk in there. I had cleaned it off, spread the pins as well as cleaning off the ground wire to starter. It cranked up just like a charm.

Thanks to all you guys, you saved me some money! Now I can winterized it and not have this problem hang over me all winter long. On to the next project of replacing a leaking tilt cylinder.

 

[Maxz695]

Re: Mercury tower of power 1115 starter will not crank 1978 I6

Good job of it sir and good luck.

 

[Lone Duck]

Re: Mercury tower of power 1115 starter will not crank 1978 I6

So mr88 had it right on . My applause to you mr88

 

[Chris1956]

Re: Mercury tower of power 1115 starter will not crank 1978 I6

That is not a 1978 motor. A 1978 IL6 will have distributor ignition and a quick disconnect plug attached to the lower cowling. You should dig up the serial number so you can buy the correct parts. That motor is closer to the mid-late 80s.

BTW, the starter is mounted in rubber. The starter bolts do not ground the starter. There should be another ground cable from the starter to the cowling support.

 

[dsay1]

Re: Mercury tower of power 1115 starter will not crank 1978 I6

The boat that it came with is a 1979 and the outboard serial no. starts with 5054..., Do you think the power head was changed out? If that was the case there still isn't a hole in the cowl hood for the quick connect.