intermitent eratic cranking behavior

[TerryMSU]

Hi:

I have a strange problem on my 1978 Johnson 35HP. The boat sometime will not crank well. Almost like a dead battery except for two things. Battery is fully charged and sometimes happens even when I use the jump function on my charger (60 Amp). It also will crank poorly one time and a few seconds later crank perfectly. I can't find any hot (temperature wise) connections and it does not seem to be connection related anyway. Actually, I thought that it was a bad ground connection on the starter (heavy connection bolted to bottom of starter at the side. That seemed to fix the problem last night, but it is back again.

I cleaned all the obvious connections and they did not make a consistent difference. That leaves either a bad starter solenoid (contactor) or maybe bad brushes in the starter. Have I missed anything?

I am hoping for a contactor issue as that is cheaper and easier to fix. What should I expect to pay for a replacement and any advice where to pick one up at?

Terry

 

[HighTrim]

Re: intermitent eratic cranking behavior

90 percent of the time these problems are connection/wiring related. Wires rot from the inside out and are hard to diagnose for failure. Make those connections shine! Rebuilding your starter is cheaper than buying new and is easy to do with a manual at hand. The battery been load tested and charged up to 12.65 volts?

You only need one jumper cable for this test, battery (+) to starter positive terminal. Alternatively, get yourself a multimeter and measure the voltage at the starter (+) terminal while somebody turns the key over to "start" - if you get within half a volt or so of the battery voltage, the starter is faulty.

Bad voltage at starter (with clean tight connections), measure the voltage at the solenoid small terminal with the yellow/red wire with the key turned over to "start" you should read within a half-volt of battery voltage, otherwise you have a wiring fault beween the keyswitch & solenoid. Good voltage at solenoid but bad voltage at starter means faulty solenoid.

Testing the Positive Battery Cable to the Engine

1. Select the DC Volts position on the meter.
2. Connect the Red (Positive) lead on the meter to the positive battery POST.
3. Connect the Black (Negative) lead on the meter to the starter solenoid terminal where the positive battery cable is connected.
4. Using a remote start switch, activate the starter solenoid to spin the engine and observe the reading on the meter. A reading above 0.6V indicates a bad cable or bad connection.
(a) If the meter reads above 0.6V, move the Black lead on the meter to the positive battery cable terminal on the starter solenoid and retest. If the reading drops to below 0.6V, the cable connection is bad.
(b) If the meter still reads above 0.6V, move the Black lead on the meter to the positive battery cable terminal on the battery and retest. If the reading drops to below 0.6V, the cable is bad or undersized.
Service Note: A bad power connection to the ignition or battery charging system can be found by connecting the Black lead on the meter to the power connection of the ignition system or charging system; then working your way back to the battery positive post. At no time should you see a reading above 1V.

Testing the Negative Battery Cable to the Engine
1. Select the DC Volts position on the meter.
2. Connect the Black (Negative) lead on the meter to the negative battery POST.
3. Connect the Red (Positive) lead on the meter to the engine block where the negative battery cable is connected.
4. Using a remote start switch, activate the starter solenoid to spin the engine and observe the reading on the meter. A reading above 0.6V is an indicator of a bad cable or bad connection.
(a) If the meter reads above 0.6V, move the Red lead on the meter to the negative battery cable terminal on the engine block and retest. If the reading drops to below 0.6V, the cable connection is bad.
(b) If the meter still reads above 0.6V, move the Red lead on the meter to the negative battery cable terminal on the battery and retest. If the reading drops to below 0.6V, the cable is bad or undersized.
A bad ground connection to the ignition and battery charging system can be found by connecting the Red lead on the meter to the ground connection of the ignition or battery charging system; then working your way back to the battery negative post. At no time should you see a reading above 1V.

 

[Benny1963]

Re: intermitent eratic cranking behavior

hi ihad asme problem my problem was bad battery cable they had eroded
in the middle of cable inside tha caseing so testing as they told you is right on
but if cables are orig and in bad condition .you might as well change them because they will leave you
benny1963

 

[TerryMSU]

Re: intermitent eratic cranking behavior

High Trim's advice was good. I checked the voltage drop along several sections of wiring. The big one was between the plus battery terminal and the solenoid. It measured 2.5 volts. I replaced the battery end terminal and that helped some. As soon as I can get a new terminal, I will be replacing the solenoid end and that should clear up the problem.

Thanks,
TerryMSU

 

[HighTrim]

Re: intermitent eratic cranking behavior

Good job, glad you found it.

 

[TerryMSU]

Re: intermitent eratic cranking behavior

After loosing another night for fishing due to motor not cranking, I am ready to replace the plus battery-to-solenoid wire. If you recall, I said that this wire was dropping 2.5 to 3 volts. Replacing the ring terminal on the wire did not fix it. I could cut back the wire a little farther, but who knows how far I would need to go.

So I am planning on replacing this wire. (The ground wire does not seem to have the same issue YET.) How do I fish the wire through the rubber tube? I was thinking about just using the old wire to pull it through after I loosen the wire clamp. Will that work?

Thanks,
Terry

 

[tashasdaddy]

Re: intermitent eratic cranking behavior

run it along side and tape it to the tube. i started to say sunday, to go ahead and replace.

 

[TerryMSU]

Re: intermitent eratic cranking behavior

Well I got the replacement cable (used but no issues with it) installed and it still has the same issue. It appears that the terminals (both battery and cable) have a little oxide build up. I filed the cable end until they were shiny and took a wire brush to the battery terminals. After that it would crank properly for a while and eventually slow down again. When I pulled the connection back off, the terminals were discolored again. I think that maybe I need a star washer or something similar to break thru the oxide layer. What do I want to use here?

TerryMSU

 

[ezeke]

Re: intermitent eratic cranking behavior

New battery cables [both] are a good idea. Ther further they run the heavier you need.

In addition to heat, you can feel a bad cable by bending it. If you feel any crunchiness anywhere along the cable, it is corroded inside and should be replaced. As it advances, the cable will have a swollen appearance at the points of the most extreme corrosion.

 

[TerryMSU]

Re: intermitent eratic cranking behavior

Bump?
Still looking for a way to make this connection more relable without making it a pain to pull the battery to charge it. (boat is stored outside, don't want to leave charger outside.)
Thanks,
TerryMSU

 

[HighTrim]

Re: intermitent eratic cranking behavior

To cure the oxidation, you should coat the terminals in a grease, then wipe off the excess.

 

[TerryMSU]

Re: intermitent eratic cranking behavior

bump

 

[ezeke]

Re: intermitent eratic cranking behavior

One thing that you may want to do is to either install a switch or disconnect the battery whenever the boat is not in use. The only thing that should be left connected is the bilge pump.

 

[HighTrim]

Re: intermitent eratic cranking behavior

This is an example of the switch he was referring to