Ground Problem?

[beerman57]

The boat of my friend that passed away this time last year, 1998 Johnson 200. The wife, Anne, called me to take a look at it – batteries just over 1 year old, but just getting a click out of the solenoid. Charge batteries but same thing, 12.8V to the solenoid but less than 5V coming out, with a new solenoid. Before this, they have been telling me that after the boat sits, it would turn over but not start until they just jumped across the 2 big solenoid terminals with metal Leatherman pliers, then it would start fine. I think they showed me it once last summer. Never ever heard of that one before. But just getting 5V out of the solenoid, ground problem? start switch? It was about to storm last evening before I could check much, I did pull the battery switch and checked resistance on the cable to the solenoid – .2 ohms. So right now I’m a little stumped and it’s about 8 miles to their house. Bad ground is about all I can think of.

[dave-bernard]

sounds like a bad solenoid to me.

[crosbyman]

if you see 5V ALL THE TIME…you are likely getting some weird back feed from the stater lead but if you ONLY SEE +5V only when activating the starter with the key then the starter internal contacts are likely shot

tried a new starter ??

if you disconnect the fat 12v input to the starter and disconnect the fat starter wire (output) and start … the selenoid should click and… you should see 0 ohms.. or very close to….. between to two fat posts . a high resistance indicates bad… pitted, corroded internal contacts .

but all being said… do make certain the black wire is properly grounded…and clean all connection points from the bat +12v up to and including starter +12v post

Joining AOMCI has priviledges 🙂

[fleetwin]

Well, you really want to start with the batteries, and cables. Sometimes batteries are mounted in consoles, or forward, which makes for a long run for the battery cables. Cables are often undersize and subject to corrosion. The way I read your post, seems like someone has already replaced the solenoid, correct? The owner claims the engine will crank normally if the two large solenoid terminals are jumped. Please be careful if you want to try this, make sure there is no gas puddled in the engine pan, and do it with the key off so the engine won’t start and scare you.
If the engine cranks normally when you "jump" the solenoid large terminals, and the solenoid has indeed been replaced, then I am thinking you have either poor positive input to the solenoid from the key switch, or a bad ground to the solenoid.
This is a perfect situation to used the "voltage drop test" that is outlined in most late model OMC service manuals for electric start engines. But, again, load test the batteries first….

[beerman57]

The previous solenoid was fairly new and this one is a new ARCO, what are the chances both are bad – .0001%? I was thinking possibly starter too, but only 5V out of the solenoid, with 1 year old, charged up batteries, 12.8V into the solenoid, .2 ohms on batt. cable to solenoid. I’ll bench test the solenoid and starter, check the grounds – but as usual, this is a baffling problem to me. Let’s say the starter is bad, would a good starter show 12.8V coming out of the solenoid (or close to 12.8V)? Starter condition doesn’t have anything to do with voltage out of the solenoid, right? This motor has been a little bit of a nightmare and someone told Anne that this age/model OMC could be problematic.

[billw]

Fleetwin mentioned the voltage drop test. This is hard for some people to wrap their head around, so think about this for a few minutes, before you try it:

First, ohm readings in a starter circuit are usually useless because you’re testing the circuit with a 1 1/2 volt battery and almost no amperage. You really have to test a starter system under load.

Voltage drop tests can test parts of the circuit, individually. What you are trying to see is how much LOSS of voltage each part of the circuit has, through any given component. In the case of the starter solenoid, you would test by putting the negative lead of a volt meter the starter motor side of the solenoid and the positive lead of the volt meter on the input, battery side of the solenoid, WHILE CRANKING the engine. Believe it or not, this will read a voltage, hopefully small. (BEFORE cranking, it should read battery voltage.) It indicates how much is LOST through the solenoid, before ever getting to the starter. If it’s more than say, half a volt, while trying to crank the engine, you probably have a solenoid problem. This is the tip of the voltage drop test iceberg; there is a lot more to test. But since you are focused on the solenoid right now, this is the best way to test it.

Long live American manufacturing!

[jerry-ahrens]

Don’t forget the primary side of the solenoid. The yellow/red stripe from key switch, and the solenoid ground. It would be a good idea to test the voltage from the key switch to the solenoid. One other thought, I have went on many service calls only to find the wing nuts on the battery finger tight. Tighten with pliers.

[beerman57]

Already tightened the cables at the batteries. So starter condition makes no difference how much voltage is coming out of the solenoid, right? A very tired starter when cranked should still have 12V coming out of the solenoid (not 5V) when 12.8V is going in? I have the old (almost new) solenoid out in the garage, if it tests OK, then it "almost" has to be bad ground.

[fleetwin]

quote beerman57:

Already tightened the cables at the batteries. So starter condition makes no difference how much voltage is coming out of the solenoid, right? A very tired starter when cranked should still have 12V coming out of the solenoid (not 5V) when 12.8V is going in? I have the old (almost new) solenoid out in the garage, if it tests OK, then it “almost” has to be bad ground.

Well, not quite….A tired starter that is drawing way too much current will throw off test results and add to confusion….
But, you mentioned the owner saying the engine cranked normally when the two large solenoid terminals were "jumped", did I understand you correctly? If so, this would seem to rule out the starter as a problem. Did you try jumping the terminals (key switch off-gas wiped out of motor pan)? You also mentioned that the owner had replaced the solenoid, is this the case?
If indeed the owner replaced the solenoid, and the starter operates normally when you jump the big terminals, then I feel it is safe to conclude that the solenoid inputs are to blame: bad ground to solenoid or voltage loss through the orange/yellow input lead from key switch….
And again, the voltage drop tests in most OMC manuals will help pinpoint the exact cause, just be sure to follow the instructions step by step starting with load testing the battery….

[beerman57]

The almost new solenoid I have with me tests fine. The weird deal with the motor turning over but not starting until you jumped across the large solenoid posts, that is just completely baffling to me. After that the motor would start fine all day, until it was allowed to sit for a week or 2, then would have jump across the large posts again. Oh, the starter never seemed to be dragging before, not that I noticed anyway.
So, as I expected, there is probably nothing wrong with either solenoid. I’ll check the grounds and volts at the yellow/red, small solenoid terminal. I’m going to start on new axles, springs and bunk brackets for this boat’s trailer tomorrow. But at 3pm there is the celebration of life for my welder friend.

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