Help, motor needs to be boosted to start

[detchon]

I took my 1993 Mercury 115 two stroke out yesterday and the battery was completely dead. I jumped it with the truck and the motor ran perfectly.
Went out on the water, and after an hour it stalled will I was idling and when I went to start it again, absolutely no juice in the battery. Had to get it jumped again while on the water.
This is the second time that I have been out this year and I had no problems with it the first time. Battery was bought new last May, so only a year old.
My obvious thought is that it is an alternator problem. How do I check if the alternator is working?
Also, I had the battery disconnected over the winter and put it back in myself and I am wondering if it is possible that I didn't connect it properly? Does the cable from the alternator need to be attached a certain way?
One other thing, all of the accessaries work; radio, trim ect. but the speedo isn't, which it was before.
I am literally dead in the water, so any help would be appreciated.

 

[Chris1956]

Re: Help, motor needs to be boosted to start

Usually there is only two thick cables from the motor to the battery. +cable will be red and run to starter solenoid. This should connect to pos pole of battery. Check this out for us and report back. That motor will have an alternator ign system, and doesn't require battery voltage after it is started. My guess is that your charging system for the battery is bad and the battery is low in charge.

 

[bktheking]

Re: Help, motor needs to be boosted to start

Speedo probably has nothing to do with charging, your boat either has a pitot on the transom that is plugged or there is a fitting on your motor which is either plugged, got air in it, disconnected or the gauge is pooched. Fire up the motor and put a voltmeter (multimeter works to) on it and check the voltage. 12-12.5 volts which doesn't vary as the motor is idled up indicates a bad rectifier or regulator. You can then disconnect the rectifier and test it. If you have a diode check feature on your meter, you can test the rectifier, if you need help let me know. If you accidently put the batt cables on backward even for a split second the diodes in the rectifier are popped.

I work in ottawa so i'm close by if you need help.

 

[detchon]

Re: Help, motor needs to be boosted to start

Okay, I went through my old posts from last year and a reply about my tach acting up suggested that it might be a bad rectifier so I think maybe we are on to something. Would a bad rectifier prevent the battery from charging and cause speedo and tach problems?

 

[bktheking]

Re: Help, motor needs to be boosted to start

Not speedo unless it's electronic (most are mechanical), tach yes for sure- the tach will quit working. Charging- most definetely. The tach pulls it's AC signal from the rectifier. The rectifier converts AC signal from the stator to DC for battery charging.

All things point to a bad rectifier. Test it before replacing, they aren't $2.

 

[detchon]

Re: Help, motor needs to be boosted to start

I read something online about testing it and it says all I need is a volt meter. Is that correct? If it is a bad rectifier, is it something I can replace myself?

 

[Chris1956]

Re: Help, motor needs to be boosted to start

Rectifer test is easy with a analog ohmmeter (voltmeter or multimeter). First remove all wires from rectifier. Set ohmmeter or voltemter to RX1 ohm setting. The rectifier has 4 connections, the three that are obvious and the fourth connection is Rectifier case (ground). Put one voltmeter lead on one of the AC posts. and the other on the positive post. Note the reading. It will be a dead short or open. Now switch leads, and the reading should switch. If it is open or shorted both ways, the rectifer is bad. If it is open one way and shorted the other way, that part of the rectifier is good. Now test the following pairs of connections. This AC post to rectifer case (ground), other AC post to positive post, other AC post to rectifier Case (ground). Id all four tests show short one way, open the other way the rectifer is good.

FWIW, I think you will find the rectifer is bad...

 

[bktheking]

Re: Help, motor needs to be boosted to start

Yes, disconnect the battery and pull the side cover off the motor (its under the cowl). There you will see a square device with 5 wires, 4 on the top posts (1 will be doubled up with a tach wire) , 2 yellow and 1 red and possibly a tach wire. It's held onto the block with 2 machine screws, 1 has a ground wire. Take a pic before you do it to make sure you replace it properly.

cheers.

 

[detchon]

Re: Help, motor needs to be boosted to start

Here is a picture of my rectifier. The colours are all different so can you tell how to do it with these colours?

 

[bktheking]

Re: Help, motor needs to be boosted to start

That's the voltage regulator not the rectifier. The rectifier has 2 yellow and 1 red wire, do you see that square unit on your motor? It may be a combo unit, they show a number of different options.

They show a test for that part

http://www.marinepartsman.com/Mercury-Marine-service-bulletins/Mercury-Mariner/1991/EN_10.PDF

But the colours are all different

 

[detchon]

Re: Help, motor needs to be boosted to start

So I am pretty sure I have the rectifier this time. I got a digital voltmeter and put it on the ohms setting and did the testing. I only got a beep(continuity???) between the two smaller terminals on the side. One was a ground and the other had a yellow wire attached to it. There was no beeping(continuity???) between any of the AC terminals in either direction. I assume that the rectifier is bad??? Please let me know before I go and order one.
Attached is a picture of it.
Thanks.

 

[bktheking]

Re: Help, motor needs to be boosted to start

Nope, you pulled the starter solenoid.

Here's a whole page of them, rectifiers will have 1 red and 2 yellow wires going to them, possibly a brown or gray for the tach.


Like I said you may not have one.

http://www.ebasicpower.com/c/OB-MERREC/Rectifiers+for+Mercury+Mariner+Outboards

 

[bktheking]

Re: Help, motor needs to be boosted to start

Should be this

http://bpi.ebasicpower.com/mm5/merc...roduct_Code=MES1782M&NOSHOW=YES&rnum=ARCAR351

 

[detchon]

Re: Help, motor needs to be boosted to start

WTF!!! Why can't I figure this thing out? I went back and looked and now I think I know where it is but I am not going to pull it until you give me the ok. It has three connections on top, two say yellow and the one in the middle says tach. Is that it? I have attached a picture. The other picture is something else with a bunch of red and yellow wires coming out. What is that?
Thanks again.

 

[Chris1956]

Re: Help, motor needs to be boosted to start

The last picture of the square device with the two yellow wires, two reds and a grey wire is a voltage requlator.

 

[detchon]

Re: Help, motor needs to be boosted to start

Ok, I think that the first picture is a terminal block so I don't think I have a rectifier. There is an empty spot just below the the terminal block where it looks like something should go but there is nothing there. How does my motor not have a rectifier? I called Hurst and asked to order one and they had a part number for it so why doesn't my motor have one and if it doesn't have one, I am back to square one with why isn't my battery charging?

 

[bktheking]

Re: Help, motor needs to be boosted to start

Look at the parts diagram gents, the sqaure unit (first pic) in the reply at 8:54 is the rectifier according to the mercury parts list, the other is the regulator. The tach isn't working which feeds off the rectifier, remove it and test the diodes to make sure it's good. Pretty sure your thumb is over the red wire, 2 yellow, 1 red, 1 tach.

 

[bktheking]

Re: Help, motor needs to be boosted to start

Here is a picture of my rectifier. The colours are all different so can you tell how to do it with these colours?

This component doesn't even show up in the electrical component list (the first one you pulled).

 

[detchon]

Re: Help, motor needs to be boosted to start

Ok, I pulled that piece and according to the parts list it is #39 which says that it is a terminal block(grey), which it is. It has ALT/YEL on the top and bottom terminal and GRAY/TACH in the middle. There was two yellow wires going to the bottom and two brown wires going to the top. In the middle there was a grey and black wire, no red anywhere. If this is not the rectifier then I definately do not have one because there is nothing else there.

http://www.mercruiserparts.com/Show...&inbr=359&bnbr=50&bdesc=Electrical+Components

I have nothing that looks like this:

http://bpi.ebasicpower.com/mm5/merc...roduct_Code=MES1782M&NOSHOW=YES&rnum=ARCAR351

 

[detchon]

Re: Help, motor needs to be boosted to start

Here are pictures of the entire starboard side of my engine. Please let me know if you see anything that looks like the rectifier.
Thanks.