3116 suddenly dies and won't restart - kinda

TitanTn

TitanTn

Active Member
Jul 12, 2015
386
Chattanooga, TN
Boat Info
1986 Saltare, 1998 400 Express
Engines
454 direct drive; twin 3116TA
Twin 3116 engines with 1300 hours each. I've never had any issues from them since I've owned them for several years and 300 hours.

Today I was running about 1100 rpms on both engines (for about an hour) and suddenly the port engine just died. Won't even attempt a start, but turns over easily. Made it back to the dock and pulled in forwards. Got into the engine compartment and after pumping the primer about 15 times, I tried the port engine again. It started immediately. Ran smoothly. So I started the starboard engine and turned the boat around (normal position). After shutting down the engines I tried the port engine again and it wouldn't fire just like before. It turns over just fine.

So where should I begin in the diagnosis process? All filters are new (like 8 hours).

Thanks.
 
It's late and I should be sleeping, but the quick answer is the 12v relay for the fuel solenoid was the problem for me...
 
Is your fuel primer online all the time? Do you have the ball valve to shut it off?
 
Yeah, you probably should be sleeping! But thanks for your answer. It gave me some ideas on what to search the forum for. In the heat of the moment I can’t recall if I was getting the solenoid clunk. I’ll go back today to check. But I do know I don’t have the box of solenoids - I have the older style.
 
Carver370 said:
Is your fuel primer online all the time? Do you have the ball valve to shut it off?
Click to expand...
I’m not sure exactly what you mean. Have the valves to shut off fuel flow and change which tank I draw from, but I’m not aware of where a valve is just for the primer.
 
This sounds more like an injector seat that is leaking compression gasses past the injector into the fuel gallery. The effect is much like getting air in the fuel system. By pumping the fuel primer you forced the air on back into the fuel tank.

The way it is acting, the bad injector seat is in cylinders 1 thru 4. If 5 or 6 was leaking, it would probably just miss on the one or both #5 or #6.

You aren't going to fix this your self because it takes a special Cat tool to ream the old injector seat if it can be re-surfaced. If it must be replaced, you still need the Cat reamer to face the new injector seat.

I had this happen at about 900 hours on one engine and when we got Cat to the boat I just had him re-face all the injector seats on that engine and reset the overheads while he was there. We sold the boat at 1400 hours and never had the issue again on either engine.

Good luck with it.............


Frank
 
Sounds like air in fuel system, and sounds like Frank knows this problem well.

However, since you just changed the Racors...make sure they are full, t handles are tight and drain plug is tight...I had a hard time getting my starboard to prime, start and run last time I did filters...it was a loose plug on the bowl (it was pretty tight, just not tight enough). Maybe, just maybe it’s something simple...

For me, a last look to make sure I didn’t do something dumb/easy, would at least give me a little piece of mind making the call to CAT.
 
Update. I went out to the boat this morning. When I first pushed the rocker switch to ON, I heard the clunk and the engine started immediately upon pressing the switch to start. Ran for a few minutes with no issue. I turned it off and then it would not clunk again. I tried and tried. No clunking on the port engine. So I pulled the solenoid and replaced it. Nothing changed. No clunk. There is some fuse/replay thing plugged in under the solenoid and I swapped it out for the starboard one - no change. I pulled the rocker switches and moved the starboard one over the port side. No change. No clunking.

Correct me if I'm wrong, but since I'm not getting the clunk, I'm thinking the priming I did yesterday didn't actually do anything to start it. It just happened to be one of the times that the solenoid worked. So I'm guessing that it's not an injector seat issue. But I don't know what to do next. Now that I'm sitting here typing, I realize I should have made a jumper to the other side of the solenoid and seen if that opened the fuel rail. But any other ideas?
 
You can check for the leaking cups pretty easily, you put a clear line on the fuel return line and look for excessive bubbles in the return fuel.

I’m sure there are other potential sources of air in return fuel but that’s how the tested our boat prior to redoing the injectors. They also ran the overhead and synchronized everything during that process as it was around 1000 hours and was never done at 250 as scheduled
 
Here is where you really appreciate the mechanical 3100 series Cat engines.

First, you isolate the air in the fuel question by substituting a clean vinyl hose in the return fuel circuit. You can see air bubbles in a clear hose, so get the engine to start again and watch the clear line until you see bubbles. If you do, stop there and go find where air is getting in the system and fix that.

The electrical part of this equation could also be the problem. With the Cat unit injection system, you have (1)an ignition switch on the dash......turn it on and you hear a solenoid open with a kind of heavy clunk which is (2)the fuel supply solenoid ($100 to $145 depending upon source) opening and supplying fuel to the injection pump. There is a (3)starter switch on the dash that operates the starter/starter solenoid. There is (4) a mini-relay (the little black box in your last photo.) It closes simultaneously with (2)the fuel supply solenoid opening so you can't hear it. (It is a $14-$16 part.) Working thru the electrics with a volt meter will take a while but it isn't hard or that time consuming. The fuel solenoid (#2) and the micro relay (#4)almost never fail intermittently.....they usually either work or not.

Frank
 
Thanks Frank. I really appreciate the info and I hope to "appreciate" the mechanical 3116 engines soon!

I'm just not sure where to start next. I've got a new fuel supply solenoid, switched out the replay and rocker switch from the starboard side (known to be working). Still no clunk when switching to ON. I will work on the air in the fuel once I get the electrical fixed - because I know if I'm not hearing the solenoid clunk, it's never going to start.

I'm willing to put in the time with the volt meter, but I don't know where to begin. I'm getting 13 volts to one side of the solenoid, but not to the other when the ignition is ON. This is the same behavior with the starboard engine and it works fine. So I'm not sure I'm testing the right thing, or maybe in the right way.
 
I have the CAT diagnostics. Let me look and see if they have a procedure.
 
TitanTn said:
Thanks Frank. I really appreciate the info and I hope to "appreciate" the mechanical 3116 engines soon!

I'm just not sure where to start next. I've got a new fuel supply solenoid, switched out the replay and rocker switch from the starboard side (known to be working). Still no clunk when switching to ON. I will work on the air in the fuel once I get the electrical fixed - because I know if I'm not hearing the solenoid clunk, it's never going to start.

I'm willing to put in the time with the volt meter, but I don't know where to begin. I'm getting 13 volts to one side of the solenoid, but not to the other when the ignition is ON. This is the same behavior with the starboard engine and it works fine. So I'm not sure I'm testing the right thing, or maybe in the right way.
Click to expand...

For a while I was running a fused jumper from 12v positive battery to the fuel solenoid... Until Frank and Barlow diagnosed the problem for me.
 
Similar problem on my 3116's...turned out to be the eyelet from the starter (if I remember correctly) that provided 12v to the engine and SV. Wire was broken so intermittent power. I was cruising at the time and used the jumper approach from the battery to SV. If you are not getting the clunk, you are not getting fuel. Put a jumper from the battery to SV and once you hear the clunk try to start it. If it runs, you are looking for an electrical problem.
 
Update with problem now known. One issue is that I was not understanding the difference between the starter solenoid and the fuel solenoid. I've been focusing on the starter solenoid and that's what I swapped out previously. It wasn't the issue.

Tonight I figured out the fuel solenoid part. I confirmed when I put power to one of the legs the solenoid would open every time. I also confirmed that the rocker switch on the dash was putting out power every time. So the issue is the wire that runs from the rocker switch to the fuel shut-off solenoid. It has a break or is grounding out somewhere. That'd be almost impossible to find so I'll be running a new wire soon.

Thanks to everyone for the info.
 
Well at least it’s cheap and easy!
 
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