Continuing Starting Problem

[bobk]

6V92 TA 425HP. This engine has baffled me and a number of service pros, both DD specialists, generalists and a good certified marine electrician. I think I posted on this before, but will start afresh in hopes for new ideas.

The port engine is at issue. If it is not run for a week or so, it can be very hard to start. The voltmeter will show ten volts or so when cranking, even with the parallel switch engaged. When I use the parallel switch, even the starboard volt meter drops, including with the starboard engine running at 1000 rpm. When it finally starts, it feels like it is not running on all cylinders for a couple of seconds.

Once it has been started, it restarts fast with a minimal voltage drop on the gage. I've demonstrated this even after just a few seconds runtime after a start so nothing has heated up. When off for a day or two, it fires off fast.

Here is a list of what has been tried to no avail:

• New pair of 8D batteries for the port bank 5 months ago.
• Engine tune up (tried this a couple of times with different mechs).
• All associated wire ends removed and new socket type ends installed.
• Starter removed and given a PM job which was basically brushes, bearings etc. Shop said the starter was good.
• Ground wire connection filed clean.
  
  Voltage drop test on connections run by marine electrician showed no problems.
  
• Primed fuel system with the primer pump to insure fuel is all the way to the injectors.
• Turned off fuel supply and return valves when shutting down for a long period to prevent drain back of fuel.

Any ideas guys?

Bobk

 

[luckydave215]

Feeble, but not completely dead, fuel pump?

 

[Avenger]

Any exhaust smoke during the extended crank?

 

[bobk]

Any exhaust smoke during the extended crank?

I will check when I get back to the boat. I'm back in the hospital with pancreatitus.

Bobk

 

[Glory]

Is no smoke, put a gauge on the fuel secondary filter, you need about 10 #s to start.

 

[captddis]

How long since the after cooler has been cleaned? Seen it restrict air and cause hard starting.

 

[Avenger]

I will check when I get back to the boat. I'm back in the hospital with pancreatitus.

Bobk

Get better. We'll wait.

 

[Fanfare]

Sorry you are ill.

Buy better whisky.

Get well soon.

 

[bobk]

How long since the after cooler has been cleaned? Seen it restrict air and cause hard starting.

The after cooler was cleaned in 2006 when I bought the boat. That's just south of 4000 hours now, most at 1000-1100 rpm. Regarding this question and Avenger's regarding smoke when cranking, When she is reluctant to start, the volt meters on both sides read 10V immediately even with the parallel switch engaged. And from the bridge, it sounds like the starter is hardly turning. The voltmeter doesn't get below 11-11.5V when it is going to start, even with the stop switch engaged for an extended crank. Seems more like an electrical issue.

BTW, I'm back home, but still not willing to walk the dock and finger pier yet. Thanks all for the good wishes.

Bobk

 

[Pascal]

I would try to eliminate a fuel or electrical issue

You need to listen and compare cranking speed between both engines. From what you explained it sounds like it s not cranking fast enough to get it started. Now, if the starter has been checked and if the batteries are new it would leave the wiring. You said the cables have been checked, how about at the battery switch? How about the cobectikns at the parallel solenoid? If the cables or terminals are corroded you re going to loose a lot of power there

If the other one starts too quickly to compare cranking speed, crank it with the shut down button pressed. Also check voltage drop with a meter, not just the dash gauge which could meniff

 

[bobk]

I would try to eliminate a fuel or electrical issue

You need to listen and compare cranking speed between both engines. From what you explained it sounds like it s not cranking fast enough to get it started. Now, if the starter has been checked and if the batteries are new it would leave the wiring. You said the cables have been checked, how about at the battery switch? How about the cobectikns at the parallel solenoid? If the cables or terminals are corroded you re going to loose a lot of power there

If the other one starts too quickly to compare cranking speed, crank it with the shut down button pressed. Also check voltage drop with a meter, not just the dash gauge which could meniff

I forgot to mention that all four battery switches were replaced in the process. The port engine sounds like it is cranking slower, but I have not been in the ER when starting for confirmation. But doesn't the low voltage reading when cranking reflect a high power draw? Bad wire ends (which were all checked) would reduce the current draw?? Or is my thinking faulty? Where do the volt meters get their signal? I can try my clamp-on DC amp meter to see what current is being drawn.

Remember this is an intermittent issue. Gayle did a test start Saturday after a three day idle period and she reported it started immediately. Weird.

Bobk

 

[captddis]

I would replace the secondary solonoid in the panel in the engine room. They do exactly what you describe when they start to fail. You can hook up a push button directly to the starter. When it does not start at the helm, try the button. If it works there you have the problem.

 

[bobk]

I would replace the secondary solonoid in the panel in the engine room. They do exactly what you describe when they start to fail. You can hook up a push button directly to the starter. When it does not start at the helm, try the button. If it works there you have the problem.

Capddis,

Thanks. Sounds like a good lead. What does the secondary solenoid do, can it be bench tested to see if failure is imminent, and where is it located? If it's the one on the starter, I'll just replace it. Tell me more about the pushbutton please. How is it wired, what size wires etc. I've seen mechanics bring these to boats for a survey.

Bobk

 

[captddis]

The second solonoid allows for small wire to go to the bridge and back. The small wire from the ignition goes to the second solonoid and sends the signal to the solonoid. then the solonoid sends power to the hi amp starter
Most big engines have this set up. Most are on the engine. Hatteras did it this way on the DD

 

[bobk]

The second solonoid allows for small wire to go to the bridge and back. The small wire from the ignition goes to the second solonoid and sends the signal to the solonoid. then the solonoid sends power to the hi amp starter
Most big engines have this set up. Most are on the engine. Hatteras did it this way on the DD

captddis:

Thanks, I'm still learning and full of questions. How does this lead to real low voltage readings? It seems counter intuitive. Where does the volt meter get it's signal? I want to believe the voltage reading is at the battery, but maybe there is my lack of understanding.

As soon as I'm up to it, I'll get a part number and change it out. I really appreciate all the help and input.

Bobk

 

[bobk]

Any exhaust smoke during the extended crank?

I tried to check this yesterday with an observer set up with a camera to document anything. As luck would have it, after sitting unused for a week, the engine fired right up with probably no more than one revolution. There was no smoke during the crank, and just a bit of 'normal' smoke for a few seconds as the engine settled in. And BTW, the voltage at the helm read 12 V during the crank, so nothing unusual there.

Scott, this somehow seems reminiscent to the low voltage reading I had sporadically when I attempted to engage the synchronizer solenoid. That was on the starboard side. Thoughts?

So, now I'll try to get my hands on a solenoid for the starter. I'm guessing big $$. Once again, can these be bench tested?

Bobk

 

[captddis]

The solenoid is an off the shelf Cole Hersee item. You need a insulated base solenoid, it is about 30.00

 

[Boatsb]

Wasn't the sync fixed with a new ignition switch? The power to the bridge from the er may now be an issue. If I remember correctly the harness brings power to te keys witches and panel with a large wire. Try getting it reerminated both sides.

Connectors can be deceiving.

 

[Boatsb]

Wasn't the sync fixed with a new ignition switch? The power to the bridge from the er may now be an issue. If I remember correctly the harness brings power to te keys witches and panel with a large wire. Try getting it reerminated both sides.

Connectors can be deceiving.

 

[bobk]

The solenoid is an off the shelf Cole Hersee item. You need a insulated base solenoid, it is about 30.00

That's a relief. Thanks.

Bobk