MEP-804A Crank duration

[Evvy Fesler]

I need help understanding how long the starter motor is supposed to stay engaged when cranking the engine as I don't have any experience with a normally operating one with which to compare with mine. I understand the relationships between the MPU, spin up speed and starter disengagement, Here's my problem... when I engage the starter it cranks the engine, but for a very short period of time. Just seconds. If I keep doing start cycles the engine will eventually start. I read in the TM that one shouldn't crank more than 30-seconds implying that the crank cycle could be much longer than my timed 3-8 seconds. What's the normal duration? Crank until it starts?

 

[peapvp]

Crank up to 30seconds. If no start abort and let starter cool down.

A fully functional 804A will start within 1 to 2 seconds crank.

the engine / fuel experts can help you with that

Peter

 

[Evvy Fesler]

Thank you, Peter! This implies that the starter motor should stay engaged with the flywheel until the engine starts or 30-seconds, whichever comes first, correct?

 

[peapvp]

Yes, that’s correct {edit}
Normally it’s 15 seconds for most generators, I haven’t looked at TM for the 804A in a while.
All these 8 hundred Gensets start usually right on the dime
So this question doesn’t come up very often.
On our auto start system we do up to 15 seconds crank and then abort, like I said even 5 seconds is already pretty “abnormal “.

only exception would be in the winter without enough pre-heat or engine warmer. Temps below 20 F
Peter

 

[peapvp]

Check your fault indicator panel

 

[peapvp]

And check your starter with the dead crank switch. If you have the same issue with the dead crank switch then you need to check / repair your starter.
If it is not, then place dead crank switch back to normal.
At this point it is either the S1 switch, K15, K16 (crank disconnect) which is controlled by governor controller via MPU

 

[Evvy Fesler]

And check your starter with the dead crank switch. If you have the same issue with the dead crank switch then you need to check / repair your starter.
If it is not, then place dead crank switch back to normal.
At this point it is either the S1 switch, K15, K16 (crank disconnect) which is controlled by governor controller via MPU

Super, thank you! I will report back soon.

 

[Ray70]

Just so that there is no confusion, what Peter is saying is that YOU should crank no longer than 30 seconds by the switch and if it doesn't start let go of the switch, let the starter cool and try again. The starter is not going to stop itself after 30 seconds of cranking if you are still holding the switch and the motor has not started. So your post # 3 is NOT really correct. It sounds like you are expecting the starter to stop itself after 30 seconds if it doesn't start, that is not the case.

 

[peapvp]

Just so that there is no confusion, what Peter is saying is that YOU should crank no longer than 30 seconds by the switch and if it doesn't start let go of the switch, let the starter cool and try again. The starter is not going to stop itself after 30 seconds of cranking if you are still holding the switch and the motor has not started. So your post # 3 is NOT really correct. It sounds like you are expecting the starter to stop itself after 30 seconds if it doesn't start, that is not the case.

Thanks Ray!

 

[peapvp]

Thank you, Peter! This implies that the starter motor should stay engaged with the flywheel until the engine starts or 30-seconds, whichever comes first, correct?

As Ray pointed out, the starter should stay engaged with the flywheel for as long as you either hold the S1 switch in "Start" or you use the Dead Crank Switch.
Either Switch should not be used for more then 30 seconds!

Only the MEP 807A has a automatic start where you set the start Switch once and then everything happens automatically

On all other MEP's you have to hold the ECS (Engine Control Switch usually labelled S1) in start until the engine has fired up and your oil pressure is above 15 PSI on your Oil Pressure Gauge.

I hope that clarifies this.
Thanks again Ray70 to point this out

Peter

P.S. What is perfectly clear to one person may make no sense to another person.......

{Edit: corrected MEP807A from push to set and from Button to Switch}

 

[Evvy Fesler]

As Ray pointed out, the starter should stay engaged with the flywheel for as long as you either hold the S1 switch in "Start" or you use the Dead Crank Switch.
Either Switch should not be used for more then 30 seconds!

Only the MEP 807A has a automatic start where you push the start button once and then everything happens automatically

On all other MEP's you have to hold the ECS (Engine Control Switch usually labelled S1) in start until the engine has fired up and your oil pressure is above 15 PSI on your Oil Pressure Gauge.

I hope that clarifies this.
Thanks again Ray70 to point this out

Peter

P.S. What is perfectly clear to one person may make no sense to another person.......

Good clarification, Peter and much clearer than what I wrote. We're on the same page. My issue is that the starter won't crank the engine for more than a second or two before it disengages. I couldn't crank it 15-seconds if I wanted to. The engine will start after five or six tries. I feel that if the started stayed engaged it would start in the 5-8 seconds that Peter points out as normal. It's just odd that it disengages so quickly.

P.S. I absolutely agree with you about wording have different meaning to different people. It's really best to dialog until everyone is satisfied that they understand. I especially appreciate when you (or anyone) points out or indicates that I've miscommunicated with you or them. It's through this feedback that I become a better communicator.

 

[peapvp]

Good clarification and much clearer than what I wrote. We're on the same page. My issue is that the starter won't crank the engine for more than a second or two before it disengages. I couldn't crank it 15-seconds if I wanted to. The engine will start after five or six tries. I feel that if the started stayed engaged it would start in the 5-8 seconds that Peter points out as normal. It's just odd that it disengages so quickly.

When you activate the starter with the dead crank switch, which should crank engine but disallows a full start, does engine keep cranking or does it drop out after 1 or 2 seconds while dead crank switch is still being pushed (activated by hand / finger)?

 

[Evvy Fesler]

When you activate the starter with the dead crank switch, which should crank engine but disallows a full start, does engine keep cranking or does it drop out after 1 or 2 seconds while dead crank switch is still being pushed (activated by hand / finger)?

@peapvp - Took a break from painting a room (who wouldn't? :0) and went out to the back of the barn to try the dead crank test. It has the same behavior as does the S1 method.

 

[peapvp]

@INOVA - Took a break from painting a room (who wouldn't? :0) and went out to the back of the barn to try the dead crank test. It has the same behavior as does the S1 method.

Great Evvy (since we don't know your name yet)
How many hours does your 804A have?

Here it goes:

1. Check your Batteries that they are fully charged and are holding the Charge - charge batteries or replace batteries

2. Check Fuse FU1 for good connection (corrosion, loose or frayed wiring etc) - repair / replace

3. Check K2 Crank Relay if it stays engaged for as long as Dead Crank Switch is in Crank Position:
Check for min 18V DC on Terminal A2 during crank - If no Voltage on A2 change Relay

4. Check L4 Starter Solenoid (same test as on a car starter, implies you know on how to work on a car) - replace or rebuild L4

If all tests are good then you either have to get a new starter or rebuilt the one you got (worn brushes etc)

The military refers to a starter as "Cranking Motor" but the Starter Solenoid is called a Starter Solenoid, in case you need to search the TM pdf's

Peter

 

[peapvp]

Evvy, for simplification, this is just the DC Wiring Diagram extracted out of the TM
not the best copy, but that's what they had in the TM

Peter

 

[Evvy Fesler]

Thanks again, Peter... I've got some things to keep me busy now!

Evvy is my nickname and everyone calls me that. My bills come addressed to Evelyn... :0)

 

[Guyfang]

1. Check your Batteries that they are fully charged and are holding the Charge - charge batteries or replace batteries

2. Check Fuse FU1 for good connection (corrosion, loose or frayed wiring etc) - repair / replace

3. Check K2 Crank Relay if it stays engaged for as long as Dead Crank Switch is in Crank Position:
Check for min 18V DC on Terminal A2 during crank - If no Voltage on A2 change Relay

4. Check L4 Starter Solenoid (same test as on a car starter, implies you know on how to work on a car) - replace or rebuild L4

All good places to start looking at. Make sure the wires on S10 are tight. Loose wires there will cause just this kind of problem. Do you get any idiot lights?

 

[Evvy Fesler]

1. Check your Batteries that they are fully charged and are holding the Charge - charge batteries or replace batteries

2. Check Fuse FU1 for good connection (corrosion, loose or frayed wiring etc) - repair / replace

3. Check K2 Crank Relay if it stays engaged for as long as Dead Crank Switch is in Crank Position:
Check for min 18V DC on Terminal A2 during crank - If no Voltage on A2 change Relay

4. Check L4 Starter Solenoid (same test as on a car starter, implies you know on how to work on a car) - replace or rebuild L4

All good places to start looking at. Make sure the wires on S10 are tight. Loose wires there will cause just this kind of problem. Do you get any idiot lights?

No lights except under voltage. It sounds a lot like a Bendix wind out. Batteries are new & charged. I’m leaning toward a bad starter, but I’ll check S10 because that’s something I haven’t done yet.

 

[Ray70]

Humm.... so are you saying the starter cranks for a couple seconds, then the sound of the starter changes and engine cranking stops, but the starter still makes noise? ( and starter is still spinning )? I think we were all under the impression that the starter motor shut off electrically after 2 seconds, At least I didn't realize it disengaged, and didn't actually stop spinning.
That sounds more like a problem with the bendix on the starter.

 

[Evvy Fesler]

Hey guys and any ladies reading this. I’m trying to remove the starter. From what I can tell there is a stud and nut on top at 11:00, and a bolt at 5:00. I removed nut from stud and bolt at bottom. Why doesn’t the starter come out? Bob and I tried tapping on it with a small mallet and it doesn’t budge. How do y’all get them out?

Help!