Cat 3116 starting problem

D

drprunner

Member
Dec 31, 2008
77
SE Florida
Boat Info
1997 400 Sundancer
Engines
Caterpillar 3116 300hp
I am experiencing random starting problems with my port 1997 Cat 3116 300hp. The other day I ran it for about 45 minutes, turned it off for about 2 hours, and then it wouldn't turn over. Starboard engine started fine. Emergency start switch did nothing. I could hear the solenoid click for the fuel pump but that was it, no other sound. After about 1/2 hour, it started fine. I took it back to my slip, didn't turn the battery charger on, came back 2 days later and it started no problem. Checked the batteries with a load tester and they are good, and after 2 days off the charger and starting the engine, they read 12.8V. I've replaced the neutral switch. This is the second time this has happened, the last time in Oct 2021 in a lock on the Caloosahatchee. Any ideas would be greatly appreciated.
 
Well…let’s start with the cheap and easy.

Are the shift levers out of gear?

Replace the start switch on the panel (they get old one crusty).
 
Next question…Are your shift lever/transmission mechanical or electrical shift? You said your replaced the neutral switch, leading to think mechanical…
 
dtfeld said:
Next question…Are your shift lever/transmission mechanical or electrical shift? You said your replaced the neutral switch, leading to think mechanical…
Click to expand...
Would he be hearing the solenoid click if it was the neutral safety switch... ? I don't know myself.
 
The Bill Collector said:
Would he be hearing the solenoid click if it was the neutral safety switch... ? I don't know myself.
Click to expand...
Good Question... I don't know for sure either. The fuel solenoid opens in the Run position Not sure if it runs through the start circuit.
 
The Bill Collector said:
Would he be hearing the solenoid click if it was the neutral safety switch... ? I don't know myself.
Click to expand...
Fuel Solenoid? Yes it will activate regardless of the neutral safety switch. The starter solenoid however will not.
The OP needs to check the start slave solenoid and its circuit breaker inside of the electrical box on the back of the engine; depending upon the year of the boat/engine..... Not much info to go on here although.
Cat 3116 Junction Box.jpg
 
Last edited:
ttmott said:
Fuel Solenoid? Yes it will activate regardless of the neutral safety switch. The starter solenoid however will not.
The OP needs to check the start slave solenoid and its circuit breaker inside of the electrical box on the back of the engine; depending upon the year of the boat/engine..... Not much info to go on here although.
View attachment 122491
Click to expand...
I would be happy to supply any info you need to resolve this.

Thanks, drprunner
 
First confirm when the ignition switch is turned on that the fuel solenoid is, in fact, opening (loud click). The fuel solenoid is mounted into the back of the fuel injection unit and has a wire connected to it.
If the solenoid is actuating, then power is getting to the engine.
If you have the electrical junction box mounted on the back of the engine open it up and put your hand on the start slave solenoid while someone presses Start. If you can feel it click then you know the helm start switch and neutral switch are functional and they are actuating that solenoid.
If it does not click there is an electrical issue between that solenoid, wiring, start switch, circuit breaker, or neutral switch. You will need a volt meter and ring out that power circuit. Rare but that slave solenoid could be defective.
If it does click but the starter motor doesn't turn the engine over then check/press the large circuit breaker button on the front of that junction box. If it still does not turn over the engine put a volt meter on the starter Bendex solenoid terminal that the larger (8 gauge) wire from the slave solenoid and measure if 12 volts are present when the start switch is depressed.
If you see 12 volts at the Bendex then most likely the starter requires replacement.
 
Last edited:
ttmott said:
Fuel Solenoid? Yes it will activate regardless of the neutral safety switch. The starter solenoid however will not.
The OP needs to check the start slave solenoid and its circuit breaker inside of the electrical box on the back of the engine; depending upon the year of the boat/engine..... Not much info to go on here although.
View attachment 122491
Click to expand...

I have the schematic. PM a if you need a copy.
 
To summarize - there are essentially two circuits that need checking -
The low current circuit from the Ign circuit breaker to the neutral switch to the helm start switch and to the slave solenoid - all that circuit does is activate the slave solenoid.
The high current circuit from the battery to the start circuit breaker in that junction box to the slave solenoid and to the starter motor Bendex solenoid.
 
ttmott,

You're moving up in the boating world, I remember when you had a 400 Sundancer like mine, and you sent me the file with the voltage parameters for programming the Nolan RS11. That was almost 7 years ago. I'm still loving the RS11 :)

I will check the 2 circuits the next time I have this problem. But since it has been occurring about every other month, it may be a while before I have an answer. In the meantime, I would like to have a backup solution for the next time it happens. If either circuit is failing, is there a way for me to bypass both circuits just to get the engine started, so I'm not dead-in-the-water somewhere on the hook.
 
drprunner said:
ttmott,

You're moving up in the boating world, I remember when you had a 400 Sundancer like mine, and you sent me the file with the voltage parameters for programming the Nolan RS11. That was almost 7 years ago. I'm still loving the RS11 :)

I will check the 2 circuits the next time I have this problem. But since it has been occurring about every other month, it may be a while before I have an answer. In the meantime, I would like to have a backup solution for the next time it happens. If either circuit is failing, is there a way for me to bypass both circuits just to get the engine started, so I'm not dead-in-the-water somewhere on the hook.
Click to expand...
I remember that! I wonder if Nolan is still in business? I'll say that I really miss the 400DA and it's simplicity but, the 52DB is a floating condo comparatively.
There is a bypass way but the starter motor and it's Bendex solenoid must not be the failure; they must be functional.
You can simply touch a jumper wire (10 gauge minimum) across the two large terminals of the slave solenoid. Extreme caution not to allow that jumper to ground to the box or other things. It will arc quite significantly as it takes quite a bit of current to pull the Bendex solenoid in. But if the starter motor works, the fuel solenoid engages, and the batteries and their wiring are in good shape it will start the engine.
 
ttmott said:
I remember that! I wonder if Nolan is still in business? I'll say that I really miss the 400DA and it's simplicity but, the 52DB is a floating condo comparatively.
There is a bypass way but the starter motor and it's Bendex solenoid must not be the failure; they must be functional.
You can simply touch a jumper wire (10 gauge minimum) across the two large terminals of the slave solenoid. Extreme caution not to allow that jumper to ground to the box or other things. It will arc quite significantly as it takes quite a bit of current to pull the Bendex solenoid in. But if the starter motor works, the fuel solenoid engages, and the batteries and their wiring are in good shape it will start the engine.
Click to expand...
Perfect, exactly what I was looking for. Thanks again ttmott!
 
ttmott said:
Fuel Solenoid? Yes it will activate regardless of the neutral safety switch. The starter solenoid however will not.
The OP needs to check the start slave solenoid and its circuit breaker inside of the electrical box on the back of the engine; depending upon the year of the boat/engine..... Not much info to go on here although.
View attachment 122491
Click to expand...
Guys, I don't have this box on my 3116's. I know that some do and some don't, what is the difference? I have heard a few folks carry spares of this solenoid as they can be a pita but an easy fix that is inexpensive. Since I don't have that box of goodies, do I have a different system?
 
Well it happened again today, same scenario. Port engine wouldn't start. I jumped the slave solenoid and it started immediately. Will replace the solenoid, still don't know the part number, but I got "Cole Hersee" off the back of it.
 
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