MEP 831a fuel pump working, not going through injector pump.

[DACollins]

Good Evening All,
I have this 831a that had overvoltage/short issues several years ago. I looked at it and then got busy. When attempting to operate it in the past, the engine ran fine, until the fault kicked in. Then it would shut down, to the best of my recollection.
I have reassembled the various pieces and parts. I did find a burnt connector J17, I have connected it to the corresponding wire on the P connector.
Now, when attempting to start the engine, it won't. I have removed the meter, injector line, etc. with the metering valve out, it will shoot fuel across the floor. Meter in, no fuel. Meter parts cleaned, lubricated and free. Governor seems to be less free than before? No recollection there.
I'm at a loss.
Thanks
Doug

 

[DACollins]

I can answer my own question here. It turns out that the plunger and fuel gauge were both stuck. On the Yanmar, the pump is easily removed with little worry about timing or alignment. Removed pump/plunger assembly, cleaned, lubricated, reinstalled and it works great.

Now to get it to produce 120v power.

 

[kloppk]

What's the AC voltage across terminals A & B and across B &C on the governor controller?
Any voltage showing on the sets voltmeter?
Any voltage at the convenience outlet?
Which contact on J17 was burnt?

 

[DACollins]

A&B - 136v
B&C -136v
Voltmeter shows 120v
Terminals on back measure 40v
Nothing at convenience outlet
J17 on J7/P7 plug burnt. Added connection through fire wall. Wire 1D16

136v between TB6 1-2-3. Unaffected by pot S1 although, only 75v when grounded to chassis.

 

[DACollins]

Should I start a new thread as the subject has changed?

 

[kloppk]

OK, having 136 VAC at the A,B,C terminals indicates the engine is running at way to low an RPM.
You need to re-adjust so that the voltage there is 178 +/- 2 VAC.
Adjusting the RPM so you have 178 +/- 2 VAC there sets the correct no-load RPM. This is necessary for the inverter to operate and to allow the contactor to close.

The steps to correctly adjust the set's RPM, Governor Controller adjustments and the mechanical governor adjustments are detailed in the -13 TM.
See the "Governor Adjustment" section in the TM.

 

[DACollins]

AH! Thank you!
I have lost the factory spring on the gov. Made one up from a carb spring. It holds the rpm (albeit too low) but factory is better. Suggestion for the best source? Yanmar local dealer or good online source? Just looking for your two cents.
Thank you!
Doug

 

[DACollins]

RPMs adjusted. 182 at A-B, B-C.
When closing circuit, K1 contactor not closing. Switch S5 seems to function ok by continuity check. Trying to follow schematic to figure out why contactor not closing.

 

[kloppk]

First thing to look at is the far left relay inside the panel.
This is K12 the fault relay. If the tiny LED inside it is lit then there is a fault and the contactor will not close.
Is K12's LED on?
Does the Voltmeter show 120 or 240 volts?

Let us know your findings. Can walk you thru how to find out why the contactor isn't closing.

 

[kloppk]

If K12's LED is off...
Here are a sequence of test steps to narrow down where the problem is.

1) Battle Short OFF
2) Connect your DC voltmeters negative lead to chassis ground.
3) Set you meter so it can read DC volts.
4) Start the generator
5) Measure the DC voltage the following points in order.
Toggle S5 to the CLOSE position and take each voltage reading.

K12-12 should be 0 volts
K12-4 should be 0 volts
K15-12 should be 0 volts
K15-8 should be 0 volts
S7-8 should be 0 volts
S5-5 should be 0 volts
S5-6 should be 0 volts
S5-4 should be 0 volts
S5-1 should be 0 volts
S5-2 should be 0 volts

Post up your findings.

 

[DACollins]

First thing to look at is the far left relay inside the panel.
This is K12 the fault relay. If the tiny LED inside it is lit then there is a fault and the contactor will not close.
Is K12's LED on?
Does the Voltmeter show 120 or 240 volts?

Let us know your findings. Can walk you thru how to find out why the contactor isn't closing.

K12 - no LED
Voltmeter shows 160

 

[DACollins]

If K12's LED is off...
Here are a sequence of test steps to narrow down where the problem is.

1) Battle Short OFF
2) Connect your DC voltmeters negative lead to chassis ground.
3) Set you meter so it can read DC volts.
4) Start the generator
5) Measure the DC voltage the following points in order.
Toggle S5 to the CLOSE position and take each voltage reading.

K12-12 should be 0 volts
K12-4 should be 0 volts
K15-12 should be 0 volts
K15-8 should be 0 volts
S7-8 should be 0 volts
S5-5 should be 0 volts
S5-6 should be 0 volts
S5-4 should be 0 volts
S5-1 should be 0 volts
S5-2 should be 0 volts

Post up your findings.

K12-12= .011v
K12-4. =.011v
K15-12=.001v
K15-8. =12.36v
S7-8. =40.94v
S5-5. =41.02v
S5-6. =.014v
S5-4. =41.03v
S5-1. =40.8v
S5-2. =26.25v


A5-A=100v
A5-B=100v
A5-C=160v

Thank you for your time!
Doug

 

[kloppk]

Doug,

When measuring the AC voltage at A5 you need to connect the meter probes as follows...
First A & B and measure AC voltage
Then A & C and measure AC voltage
Then B & C and measure AC voltage
Let us know what voltage you have at these 3 points.

Do you have good batteries installed in your set?

The DC voltages you measured at the various sequence of points doesn't make sense. One should never see any DC voltage along that path that's greater that ~ 28 VDC.
Seeing ~ 40 VDC isn't right at all. There isn't any DC voltage greater than ~28 volts anywhere in the set.
Having the DC voltages as you progress thru the sequence of test points go up and down doesn't make sense either. It should only be ~0 VDC. ~28 VDC should there be an issue.

 

[DACollins]

Doug,

When measuring the AC voltage at A5 you need to connect the meter probes as follows...
First A & B and measure AC voltage
Then A & C and measure AC voltage
Then B & C and measure AC voltage
Let us know what voltage you have at these 3 points.

Do you have good batteries installed in your set?

The DC voltages you measured at the various sequence of points doesn't make sense. One should never see any DC voltage along that path that's greater that ~ 28 VDC.
Seeing ~ 40 VDC isn't right at all. There isn't any DC voltage greater than ~28 volts anywhere in the set.
Having the DC voltages as you progress thru the sequence of test points go up and down doesn't make sense either. It should only be ~0 VDC. ~28 VDC should there be an issue.

Set running
Measure voltage @A5. - A,B,C
A&B 181.5V
B&C. 181.5V
A&C. 181.5V

Battery is quite old. I do measure 27.4vdc at battery, unit running.

The other higher dc voltage doesn't make sense to me either. For example, the hour meter doesn't run, but gets 40v on one terminal, 21 at the other.

Could I be getting stray voltage in the inverter?

 

[kloppk]

Now that you have the correct AC voltage at the ABC terminals on A5 what does the sets AC voltmeter indicate for voltage?

Carefully measure the AC voltage between the following terminals on top of the inverter under the plastic cover.
L0 to L1
L0 to L2

Is the LED illuminated inside K15 (the far right relay) when running?

Let's explore your measuring 40 volts on one of the hour meter terminals...

Where are you connecting your meters negative lead to for making that measurement?

I'd suggest using the ground stud on the back panel above K14 labeled CB-GND.
Measure the terminals on the hour meter. If you get one above 28 volts DC then you need to trace back in the circuit towards the battery to locate why you are seeing such a high DC voltage.
Points to measure in order for correct DC voltage (~24 VDC) are:
CR2 both leads
S1-4
S1-5
S19-2
S19-1
CB1 both terminals
Battery Positive
Battery Negative

Post up your results when you have a chance.

 

[DACollins]

Now that you have the correct AC voltage at the ABC terminals on A5 what does the sets AC voltmeter indicate for voltage?

Carefully measure the AC voltage between the following terminals on top of the inverter under the plastic cover.
L0 to L1
L0 to L2

Is the LED illuminated inside K15 (the far right relay) when running?

Let's explore your measuring 40 volts on one of the hour meter terminals...

Where are you connecting your meters negative lead to for making that measurement?

I'd suggest using the ground stud on the back panel above K14 labeled CB-GND.
Measure the terminals on the hour meter. If you get one above 28 volts DC then you need to trace back in the circuit towards the battery to locate why you are seeing such a high DC voltage.
Points to measure in order for correct DC voltage (~24 VDC) are:
CR2 both leads
S1-4
S1-5
S19-2
S19-1
CB1 both terminals
Battery Positive
Battery Negative

Post up your results when you have a chance.

You Sir, are a fountain on knowledge! I could only hope to ever gain a portion of your knowledge and insight that you've displayed. Thank you!

K15 - No light
L0-L1 = 0v
L0-L2 = 0v


CR2 = 27v
S1-4 = 27v
S1-5 = 27v
S19-2 = 27v
S19-1 = 27v
CB1 = 27v both terminals

Battery, engine running = 27v

A8 ( P17 - 11) = 40v (which eventually leads to M3-2 that reads 40V, along with S5-5 and S7-

I am concluding that the Inverter is malfunctioning. 40v where there should be 28 and no line voltage.

Am I concluding in the correct direction possibly?

Many thanks!
Doug

 

[kloppk]

There certainly shouldn't be 40 VDC on P17-11.
K8 inside the inverter should only pass thru whats at P17-12.
Seems something is afoul inside the inverter.
Weird that you measure 0 VAC at the inverters L0, L1, L2 terminals but the set voltmeter is showing 160 but you measure 40 volt at it's terminals.
The 40 volts just isn't right on P17-11 and at the voltmeter. I'll post up up if I come up with any ideas of what to look at next.

 

[DACollins]

There certainly shouldn't be 40 VDC on P17-11.
K8 inside the inverter should only pass thru whats at P17-12.
Seems something is afoul inside the inverter.
Weird that you measure 0 VAC at the inverters L0, L1, L2 terminals but the set voltmeter is showing 160 but you measure 40 volt at it's terminals.
The 40 volts just isn't right on P17-11 and at the voltmeter. I'll post up up if I come up with any ideas of what to look at next.

Thank you. I'm certainly in the dark on this.