MEP803A Resistor - Diode Assembly

USAMilRet said:

I put varying loads on the genset for 3 hours. Put 40% then 65% then 85% loads on it. All ran OK with no issues.

There is something that I noticed today but it came home this way. I do not think the motional transducer is operating properly. The starter pinion gear is not disengaging when the genset starts and reaches 900 rpm.

I tried to measure for dcv across the transducer. I think I recall reading that there should be about 3vdc or so. Still looking into it. Anyways there was no dcv across the terminals. When I removed it there was some junk on the magnet so I brushed that off and I am getting about 150 ohms across the transducer.

Any ideas on this one?

Click to expand...

Read the book partner. 2.5-3 volts AC!! The closer to 3 volts the better, but NOT over. When ever the starter clashes, it the mag pick up. No other reason for it to happen.

USAMilRet said:

Take a look at the butcher soldering job. It was butchered. Leads were cut and resoldered and the solder joints are questionable. The varisror was 67 cents and the diodes 54 cents each. Yes I will replace them. Sometimes even if it works, it has to be fixed or tweaked. Replacement of these parts is easy and it will look so much better.

Click to expand...

The thing works. Leave it be. Fix things that are not working right, or that are a problem. THEN, go back and fine tune. If you even need to. It may look bad, but if it works, don't fool with it. As I posted, the plastic stand offs do not like heat. The more you fool with it, the more likely they will break. If you just have to fix it, then try and find some plastic stand offs, so just in case they break, you are not dead in the water even longer.

Guyfang said:

Read the book partner. 2.5-3 volts AC!! The closer to 3 volts the better, but NOT over. When ever the starter clashes, it the mag pick up. No other reason for it to happen.

Click to expand...

Yeah I got it. AC 2.5 to 3.0 across 3 and 6 of the relay switch. I found it in the manual. I usually do not do things unless I am absolutely sure of the process.

So I adjusted the mag pickup to 2.6VAC and locked in place. Pinion gear now disengages properly.

Guyfang said:

The thing works. Leave it be. Fix things that are not working right, or that are a problem. THEN, go back and fine tune. If you even need to. It may look bad, but if it works, don't fool with it. As I posted, the plastic stand offs do not like heat. The more you fool with it, the more likely they will break. If you just have to fix it, then try and find some plastic stand offs, so just in case they break, you are not dead in the water even longer.

Click to expand...

This is fine tuning time on this machine. It is still a couple of days for diodes to arrive along with varistor. One final check and look over before the full 8 hour load test. Got to find a door though. In the mean time I am going to make a replacement as best I can. Got to find a break first. I can cut one out of wood easily enough for the time being.

Just in time for this machine as my gantry is due to be delivered on Mon and I will be able to get back to my first set and finish the teardown so I can start the cleaning and polishing and then the rebuilding.

USAMilRet said:

You are right about the skyrocketing prices of these units. Sorry I stepped on your toes on the bidding. What did you pay for your one out of Albany?

On this one, I got lucky.......

Click to expand...

It's gonna make you cry... Grand total from GL at the time, $722. There's still deals out there,but you gotta be both patience......and lucky with the auctions.

I figured it was about there. Yep, the days of under $1k MEPs is gone. After the hits from the hurricanes last year, seems like 50% to 200% more people are bidding on these.

USAMilRet said:

I figured it was about there. Yep, the days of under $1k MEPs is gone. After the hits from the hurricanes last year, seems like 50% to 200% more people are bidding on these.

Click to expand...

Well, there was one add on C-list i found somewhere in OH that a guy was getting rid of 3 803A at a $1000 a piece. All were non running units that the seller says they had water in the oil. Would make a good parts unit if it couldn't be fixed. Their still out there...just got to have patience.

kavesman1 said:

Well, there was one add on C-list i found somewhere in OH that a guy was getting rid of 3 803A at a $1000 a piece. All were non running units that the seller says they had water in the oil. Would make a good parts unit if it couldn't be fixed. Their still out there...just got to have patience.

Click to expand...

That is only about an hour from me. Not sure I'd want to spend $1000 on units with water in them though!

I believe the correct engine oil for these engine is 30wt. Or 10-30w. Be sure to add ZDDP engine oil treatment for the flat tappet camshaft.

lindsey97 said:

I believe the correct engine oil for these engine is 30wt. Or 10-30w. Be sure to add ZDDP engine oil treatment for the flat tappet camshaft.

Click to expand...

I use this in my M1038 as a little extra insurance, hadn’t thought to add it to the gensets.

When I read the packaging, info on the yuge jungle sales site almost every one says for use in OLDER engines, pre-1989.

Around here - there, other sites, conversations with mechanics - I’m hearing “use zddp for added insurance, there isn’t enough sulfur added to ULSD these days to matter - but you still read about used diesel trucks (Rams, 2500 GMC and others) with in excess of 150,000 to 200,000 miles.

My brother-in-law owns a ‘92 H1 Diesel with over 200k on it since he got it new.

So what’s really happening, or happened already? Low sulfur, no sulfur, roller lifters (6.2L GM engines got those), flat tappets?

Thanks in advance.

Norm

USAMilRet said:

I put varying loads on the genset for 3 hours. Put 40% then 65% then 85% loads on it. All ran OK with no issues.

There is something that I noticed today but it came home this way. I do not think the motional transducer is operating properly. The starter pinion gear is not disengaging when the genset starts and reaches 900 rpm.

I tried to measure for dcv across the transducer. I think I recall reading that there should be about 3vdc or so. Still looking into it. Anyways there was no dcv across the terminals. When I removed it there was some junk on the magnet so I brushed that off and I am getting about 150 ohms across the transducer.

Any ideas on this one?

Click to expand...

I know this is responding to an old post but the MPU (Magnetic Pick Up) can be unplugged by the starter. It produces an AC (not DC) voltage of between 2-3 volts AC. If it is below that, loosen the locknut and turn it clockwise 1/8 turn at a time and then recheck.