Outboard Mercury starter problems?

Well I have a 1979 200hp mercury outboard motor. I am getting a little mad at this motor because it is one thing or another, i know thats boating. The now is my starter. I have some what new batteries, about two years old, brand new clean cables that are 4 gauge, brand new stator, brand new plugs, brand new silenoid starter switch, brand new rectifier, and the starter was just rebuilt by a shop. I was on the water fishing and i tried to start the motor to go to a different spot. I tried to start the motor and the starter was turning the motor like the batteries were dead. The starter started off fast and then it slowed down to a crawl. I got the boat out of the water and home to do a little testing. I put the batteries on the charger to make sure they had a full charge. I checked the bateries and both had 12.53 volts before I tried to crank the motor over. The motor cranked over very slow and the meter read 10.46 volts while cranking at the battery. I them moved to the starter realay silenoid and tried to start the motor and the meter started at 12.5 and went all the way down to 8.00, on the volt meter in just 4 seconds. I stopped cranking the motor and the meter went back to 12.5. I took the flywheel cover off and turned the flywheel by hand. I was a little tought buy not to hard to turn. compression is good and not to high/around 112 psi for all 6. I have a couple of questions. even though the starter was rebuilt can it be bad. can i test the starter and how. Why is there that big of a drop in voltage. I even hooked up my brand new truck battey up to the motor and still had the starter cranking slow. Does any one have any sugestion on what to do about the slow cranking of the starter, should i buy an new starter or is there something else going on taht I am over looking. Any help would be nice. Also dont tell me that I need to clean all the connections please because I have done that already.

Re: Outboard Mercury starter problems?

get a new starter fixing a fixed broken starter sounds like more headache than is worth

Re: Outboard Mercury starter problems?

That may be the longest paragraph I have seen lately, Jeremy. Makes it hard to focus on relevant facts.

While attempting to start the battery voltage drops to about 10.5, but the voltage out of the solenoid drops to about 8. That does not compute unless the solenoid is failing hot.

Re: Outboard Mercury starter problems?

i know, i am confused also. I bought another solenoid, and still no diference in voltage

Re: Outboard Mercury starter problems?

Have you checked and cleaned all the connections?

Re: Outboard Mercury starter problems?

Depending on the build number that engine could have either the bosch or prestolite starter and possibly the fine tooth flywheel which no bendix or starter is offered by aftermarket suppliers.

Re: Outboard Mercury starter problems?

really

Re: Outboard Mercury starter problems?

JB said:

That may be the longest paragraph I have seen lately, Jeremy. Makes it hard to focus on relevant facts.

While attempting to start the battery voltage drops to about 10.5, but the voltage out of the solenoid drops to about 8. That does not compute unless the solenoid is failing hot.

Click to expand...

Yes, it does compute. The starter is drawing way more current than it is supposed to, and there's 2 volts drop across a length of 4 gauge wire. I'm guessing 250-300 amps instead of the 125 it is supposed to draw.

That starter is vertically oriented, with the end contact brushes and their holder on the lower end. Carbon and copper dust from normal operation accumulate around the brush holders till it shorts out the brushes.

I would guess that if you're hitting it with truck batteries and listening to it turn slow that you've completely fried the starter by now. You might as well just go get a new one. While you're at it, get and install a new starter solenoid. You've put that one through way more stress than it was intended to take.

hope it helps
John

Re: Outboard Mercury starter problems?

Jeremy78 said:

i know, i am confused also. I bought another solenoid, and still no diference in voltage

Click to expand...

Hadn't noticed you bought a new solenoid. It's probably OK.

Faztbullet said:

Depending on the build number that engine could have either the bosch or prestolite starter and possibly the fine tooth flywheel which no bendix or starter is offered by aftermarket suppliers.

Click to expand...

How do you tell the difference?

Re: Outboard Mercury starter problems?

How do you tell the difference?

Click to expand...

The prestolite will have 2 slotted screws in the side of starter housing to hold the field/frame in place, the bosch is a permanent magnet motor...

Re: Outboard Mercury starter problems?

j_martin said:

Yes, it does compute.
hope it helps
John

Click to expand...

"That does not compute" means that it should not happen, John. Forgive my use of slang.

Re: Outboard Mercury starter problems?

I thank everyone for the advice on the starter, i have taken the starter to 4 shop and every shop does not have a meter that will give me amp draw. The only thing they can tell me is that it is drawing 9 volts on a bench test. I have spent too much money driving my truck around trying to get a fix on the starter. does anyone have a suggestion on what type of new starter i should get. the motor is a 1979 200hp mercury outboard, with a serial number of 5159987. Also i will double check the battery cables to make sure that there are no kinks in them causing the bad voltage drop. Also, when trying to start the motor, the motor starts cranking slow then it gets faster, then it goes back to cranking slow

Re: Outboard Mercury starter problems?

Go to NAPA, get an amp tester that you hold against the wire.

Put the starter back on the motor, hold the gauge against the wire to the starter, and crank it.

You will find it draws very high current. (like 250 or so). It should be 125 or so.

Kinking a wire won't choke it off like a garden hose.

9 volts on a bench test? WWWHhatt is with that?

View attachment 110273

https://www.napaonline.com/Catalog/CatalogItemDetail.aspx?A=BK_7001083_0006398680&An=0

I have thoroughly explained to you what is happening. If you had that much voltage drop and it wasn't in a large part like the starter itself, you'd have visible smoke in a few seconds. I've been fooled into thinking I had a bad battery doing things by ear. The meter isolates the problem. Odds are 99/1 that it is a bad starter.

Re: Outboard Mercury starter problems?

JB said:

"That does not compute" means that it should not happen, John. Forgive my use of slang.

Click to expand...

Only hits on 3, pulls 6000 rpm into a 26 chopper on a 20' bass boat, 66GPS......does not compute. (impossible)

Only hits on 3, pulls 6000 rpm into a 26 chopper on a 20' bass boat, only 16 GPS....computes. (possible.....with bad prop)

Does not compute means an impossible combination of symptoms. OP's symptoms compute to a bad starter.

a "does not compute" is caused by a mistaken reading, for instance the worker overhauls the fuel pump, but forgets a check valve. The "fuel pump is good" factor makes the analysis of symptoms fail to resolve, ie not compute.

Sorry for being so picky. You could have just let it ride.

Re: Outboard Mercury starter problems?

9 volts on a bench test, that is what the last two people have told me about the starter. I told them both that I wanted to know the amp draw on the starter was and they looked a little puzzled. I am going to napa to get a meter in the mourning, i will let you know what the meter reads

Re: Outboard Mercury starter problems?

Am I missing something or am I not? He's not mentioned load-testing the batteries. Even though he said he tried his truck battery I think that the voltage dropping below 10.5 is bad news. And if he has two batteries that are 2 years old it is very possible that one is bad and is killing the second.

I also note the "4 gauge" wire comment. Do you mean 4/0? AWG 4 wire is not big enough to handle starting circuit loads and will result in severe voltage drops. In fact I have AWG 4 wire for my 24V trolling motor. That's a little overkill for that application but waaay too small for a starter.

As far as the starter, if the nose bushing is worn and is allowing the shaft to drag when there is a load on it that can cause the excessive draw and slow operation. Electrical repair houses may do brushes, armatures and the like but often overlook the drive section. Even though the electrical section is rebuilt the rest of the starter may not be. Check with them on what they do when they "rebuild" one.

And unless he hooked up a big truck to his boat (like a large commercial diesel that runs on 24V) he'll not ruin the starter- it'll draw what it wants. The battery capacity makes no difference. Granted, having that capacity may allow the starter to draw enough to damage itself through heat.

Re: Outboard Mercury starter problems?

both batteries are new. Yes they are two years old, but they have only been used to start the boat, nothing else. Well i took the starter apart again to see if there was any thing that didnt look right. the only thing thereplaced was the armature nothing else. all the brushes were cracked in half and the brushes were already turning black. I am going to cut my losses with this starter and buy a new one. Also I have a awg 2 wire for the ground and a awg 4 wire for the positive(that is the biggest I could find). The wires that i replaces were only a awg 6. When the new starter comes in I will let everyone know what is going on.

Re: Outboard Mercury starter problems?

Even though your batteries are only two years old, i would load test them, seen batteries fail that were a lot newer than that. Have you checked the water level? You say the cables that were replaced were 6 awg, were they original? How long of a run from engine to batteries, you haven't moved them by any chance?

Re: Outboard Mercury starter problems?

Well, it has been a long time since i started my post, but we finally got to the bottom of things. The whole time i was having trouble it was the starter. I broke down and bought a new starter. In total i spent almost $800 on all new parts and pieces, when i was told that the starter was good. I spent more money having my old starter rebuilt than i did on a brand new starter. The motor runs like new now. I thank everyone for their input.