Genie laboring and drop off in amperage

[alchemy]

To Ample Power support from Dick Stevenson on Alchemy
Below is the first problem that I was addressing when I caused a short that lead to me needing to address the Activating SAR issue in the previous thread.
Problem: Genie laboring and drop off in amperage
This problem refers to a;
Ample Power Genie, model G12-150 using:
Kubota (numbers off engine)
EL 300-E2-ER. code #, 1G106-00000. s/n, 5E0998.
Model # E300-ES.
The unit has 850 hours of use.
Sequence of events:
1. Oct 3. Smoke comes out of genset (GS) area. I immediately shut it down. No discernable evidence of where the smoke came from but did find the belts loose. Decided to replace belts and then found alt loose at pivot bolt and 2 of the 3 pos leads on the alt going to the remote diode assb (rectifier) loose. They were under caps which were impossible to move for inspection and had gotten “fused” on over time.
2. Replaced belts & tightened all electrical connections and checked everything.
3. Ran GS through one full charging cycle and all seemed good.
4. All seemed good for a couple of days running the GS for about 1 ¼ hr each day.
5. Oct 6-7. Thought I heard the GS lugging (laboring) a bit at onset of charging when the GS is being asked to put out 145 or so amps. Seemed ok when amperage output went down and ran a full cycle of charging.
6. Oct. 8. Continue to think I hear a very slight laboring. No smoke from exhaust. Oil pressure normal. Oil level normal. Good water flow.
7. Oct 9. Run GS and continue to think I hear lugging. After a few minutes I hear the GS starting to wind down to a stall and I flick off the regulator just before stall and the rpm increases. I give it a minute or 2 and flick on the regulator again. Output again 145 or so, and even though lugging, the GS stays running, but the amperage output decreases rapidly and after 5-10 minutes goes down to 20+ amps output when it should be putting out much more. The GS also just does not sound strong.
8. I explored a number of notions (see below) and then I dug into the stern under the lazarette to where the rectifier resides. The insulation on one of the 3 wires going to the stator taps from the alt was charred at the end and down about 3-4 inches. The whole area looked like it had endured high heat. The connection was tight so I have no idea what caused the heat buildup. The rectifier looked fine and tested fine with a diode tester, just the terminal bolt looked like it had been hot. I cut back to good insulation & metal on the wire and replaced the terminal.
9. Took alternator and rectifier to shop for bench testing. All fine.
10. The GS went back to its normal functioning through one cycle of charging.
11. The next cycle the engine starts lugging and dropping rpm preparing to stall after 2-4 minutes of putting out 145 amps. (It has been normal for the first few minutes to have high amp output.) I turn the regulator off and the eng returns to previous rpm. I check all terminals and wires and connections and all are at OK temperatures (pyrometer) and nothing looks amiss. I restart regulator and with a bit of a leg up from the previous few minutes of charging, the cycle of charging continues and proceeds more or less normally. All wires and terminals remain at ok temps and look fine. Engine still sounds a little labored.
12. Replaced SAR (which is when I caused the shorting that started this correspondence). No difference in symptoms.
Speculations on my part:
1. Throttle is turned down: Checked, seems fine. I would think that if that were the case, the GS would continue to put out amps, but just be unable to sustain full amps.
2. Fuel deprived: Checked fuel filter vacuum gauge to see if indicates clogged fuel filter. Reads fine. Again, why would the regulator be decreasing the amperage output?
3. Air filter clogged: Checked. Normal dusting. Replaced with clean. Again, why would the regulator be decreasing the amperage output?
4. New belts slipping: Checked, tension seems fine. But I have heard no squealing and again why would the amperage output steadily decrease looking as if the regulator is seeing full batteries?
5. Removed exhaust elbow and it was clear of any obstruction. Good water flow. Through exhaust and siphon loop.
6. I am at a loss to explain most any of the above. I planned to do a tune this winter as it is the required # of hours for a valve adjustment. Could this be the problem?
7. The problem appears twofold, one being the laboring engine at amperage outputs it has been used to (points to engine problem) and two, the rapidly dropping amperage output when the engine is not having a lot asked of it (points to regulator electrical problem). I would think that the SAR would continue to ask for amperage for depleted batteries and if the engine could not cope, it would stall. Why, if the engine is going does the amperage drop

Note: One other thing going on with the GS this summer is that it seems to take longer to get up to operating temperature. It takes about 20 minutes. I noticed this at the beginning of the season and attributed it to cold water. But it seems to have continued. I could be wrong. With this GS I worry I might be seeing ghosts.

[Coulomb]

As always, we need the measurements from the Troubleshooting Guide to diagnose the problem.

[alchemy]

Below please find the trouble shooting guide figures. (Oct 31, 2010)
Row Col A Col B Col C
1/na 0.00 0.00 0.00
2 0.00 12.28 13.84
3 0.00 0.00 0.00
4 12.83 12.73 14.38
5 0.00 10.13 7.95
6 0.00 0.03 0.04
7/na 0.00 0.00 0.00
8 12.80 12.80 14.40
9 0.00 0.00 0.00
10 2.97 2.97 2.98
11/na 0.00 0.00 0.00
12/na 0.01 0.04 0.01
13/na 12.75/0.00 12.75/0.00 12.75/0.00
14 12.83 12.81 14.42
15/na 0.00 0.00 0.00
16 12.75 12.75 12.75
Thanks, Dick

[Coulomb]

The current is declining because the absorption state has been reached
and that's to be expected.

Please read this post on the forum.
http://www.amplepower.com/phpBB3/viewtopic.php?f=3&t=36

There is more battery management information in the Primer here:
http://www.amplepower.com/primer/index.html

And the book "Living on 12 Volts with Ample Power" has a chapter on
battery management and what to expect.

[alchemy]

This is the problem in a nutshell. My Genie is stalling under conditions where it was running well a month ago. Today it ran for 15 minutes and then started stalling and the only reason it did not stall was because I turned off the regulator. Do you have any thoughts or suggestions as to why this is occuring?
Thanks, Dick

[Coulomb]

Assuming that the regulator is current limiting, this problem has always proven to be lack of fuel. Causes include a bad fuel pump, air in the line, and drawing a vacuum on the fuel tank, even though the main engine runs OK from the same tank.

[alchemy]

Ample Power Help Site
I have checked (or had checked0 the following in the fuel system;
1. Solenoid
2. Lift pump
3. Fuel hose
4. Injector fuel pump
5. Injector nozzle
6. Fuel quality
7. Valve clearance adjustment
8. Oil change
Checked by other professionals
1. Alternator and rectifier
Checked by owner
1. Exhaust elbow is clean & clear
2. Cooling water flow
3. Air filter
4. Oil pressure & level normal
5. No black smoke out of exhaust. Exhaust looks the same.
6. Rectifier is staying cool.
7. Fuel filter clean, vacuum gauge good, Propulsion eng running off same fuel system runs fine at cruising rpm.
All areas mentioned above check out fine.
Started the Genie and pretty quickly started the lugging/stalling reported earlier. It was also “dieseling” (running on) a regularly. This is something it has done every now and again in the past (especially when the GS is only run a short period, like recently in thetesting). As said above, the solenoid checked out fine.
I really look forward to your thoughts, as I am stumped.
Thanks, Dick

[alchemy]

Ps, The regulator is current limited. Dick

[Coulomb]

What are you using for a fuel pump? Does it also feed the main engine?

We've witnessed first hand a gravity tank feed to both the main engine and the Genie where the main engine ran fine, but the Genie would load down and stall after a short period. The problem turned out to be a small 'valley' in the vent line for the tank. The valley was filled with diesel fuel so the tank wasn't vented enough for the Genie, but the main could pull enough vacuum on the tank to get air through the vent tube.

We found the problem using a small gravity tank we took to the boat and the Genie ran fine.

[alchemy]

I will explore the vent for valleys. The lift pump is dedicated to the GS. Would cracking open the fill cap (another vent) for the fuel tank test this out? Thanks