What are points for a 4A084 III supposed to look like?

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ida34

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Dexter, MI
I finally got around to working on getting my MEP018A gensets working. I only got them about 4 years ago or so. I have two on a M103 trailer so I started with the rear one. I have new carbs I bought a couple of years ago so I am just throwing them on. I also put acid in my 4hn battery I got a few years ago. Throw in a slave cable and a puff of starting fluid and I was ready to start. I figured the carb might have bad gas but when I checked it was dry. While I was at it I checked for spark since the starting fluid should have at least fired it. I almost forgot, it already had new plugs as I played with it for a day a few years ago. Since the spark was inconsistent and weak I decided a magneto tune was in order. I pulled apart the mag off and the two lower plug wires were loose. I still pressed ahead figuring the points probably needed it anyway. I found the rotor was severely worn at the middle. The cap did not look much better. I loved the lead gasket. When I looked over the points they were barely opening and in bad need of adjustment at the very least. The contacts were also not pretty.

Now to the question at hand. The points either burned off at an angle or they came that way. I will find out for sure when I get the new set. For those that have changed or at least seen them, are they cut at an angle or are the flat?

It would make sense if they were flat and burned away at an angle as that amount of material would have closed the gap like I had seen. I ordered the parts from Saturn and hope to have them for this weekend. I will take pics and post when I have time.
 

jbk

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the points surface should be flat. seems like i removed the mag to change points and cond. and adjust the gap. seems like it was .0018. anyway the governor needs to come off the front of the engine then mark the mag. before removal that way your timing will be close. i put a timing light on mine after.
 

ida34

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That is pretty much what I figured. The gap was probably not adjusted right and it burned off at an angle. I will have to post a pick. I had never seen points burned like this.

Just to be clear. The point surfaces are flat but at an angle instead of being an exact 90 degree right angle. It is so flat it gave me pause to think it might have been designed that way. The contacts are burned but still flat to one another. I probably could have the proper gap and had them work but I would have had to file them too and it was much easier to get new ones.

I will post a pick when I can.
 

callbt

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Peoria IL
4A084 condesnor & ground issue- no spark

Hello, I'm working on a 10KW genset with a very well weathered (low hour) 4A084 engine. I got the mag open (Fairbanks Moris) to discover the seal didn't keep the water out. My question is: how do I verify the condensor is still good? Also the grounding wrap around the white wire going to the mag must be grounded for the entire system to work (turn over with the control panel switch). To me this seems wrong that the only ground to the entire engine control panel is thru this small braided cover around the white "kill" wire. Any tips on timing the engine would be great- I'm used to my old 73 VW, just not used to the magneto that ALSO has a condensor (thinking of my old hit and miss engine with a magneto spark). Thanks Brian
 

jbk

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saturn surplus is where i got most of my parts. somtimes they have the points/cond. and somtimes not. their are some new slick gov. repacement mags. on ebay at a good price. i picked up a 24 volt timming light to do mine. i had set the timing up by the tm manual first and the light showed i was still off. so i would recomend the light.
 

callbt

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Peoria IL
Slick vs Fairbanks Morse mag swap on 4A084

Thanks JBK, Can I install a "slick" magneto inplace of a fairbanks morse? From the pictures I've seen, the mounting looks very different.

Still need a way to verify the condition of the Condensor- thoughts? I used to use my old needle style VOM and simply charged up the condensor from the VW Bug and watched the voltage drop off.. now with this engine, it's driven by a mag, so guessing I'd have to spin the mag a few times to charge the condensor.

yep looked at Saturn's web site for parts. I need a top cover for the engine too, but thinking I'll wait until I visit home in Rolla Missouri, then it's just a short trip to Lebannon MO / Fort Leonard Wood to hunt for parts.

Thanks Brian
 

callbt

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Peoria IL
The beast is alive- the points had heavy oxidation- cleaned, but not filed, regapped and she's up and running. I discoverd the plastic gear that runs the tacometer output was crewed up due to the shaft being stuck- any concerns of plastic bits floating in the oil?

For now the fuel pump is bypassed with a gravity feed system for trouble shooting.. any good ideas for a fuel tank on these setups like a beer keg?

Still in need of a top cover for the engine.
 

jbk

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i changed the cond. and points on all mine i never gave a thought to checking the cond. the govt. slick mag. is to replace the fm. it comes with th necc. brackets. ive installed it in 2 units comes with new plug wires also. i think its 149.00 at ss some on ebay for 129.00. i had one chew the plastic tack. gear also i think it just consumed the plastic. the fuel pump is 40.00 at ss. i use a 12 gal. plastic marine fuel tank from wm. for 50.00. dont idle this set either it will take out the a/c vr in about 1 min. i bought a hood from ss for 50 bucks.
 

callbt

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Peoria IL
Thanks for the info, I'll look at getting a plastic marine tank. Looks like I'll keep the FM magneto since it appears to be functioning for now.

Whas is the A/C vr? wondering if I didn't toast it last night while I was getting the engine to start- had some slower times when the choke was on too strong and the engine wasn't up to speed compared to later. How do I check this A/C vr and where is it located? I'm only used to dealing with the current gen sets from the box stores, where faster is more volts and higher hz.
 

jbk

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livingston la.
the a/c reg. is located in the bottom left of the control box. open the panel let it tilt down and take a look. if it went south then volts would be low or fliuctuating on this set, i think. check your set at the convenice receptical in front or at the output lugs and see if you can still adjust for 120 or so. i bought a couple nos reg. for 250.00 a piece and was glad to find that. you need to check the htz. (engine speed )also. those anolog gauges ar not to exact.
 

callbt

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can I simply unhook/unplug the generator from the control panel to avoid frying any electronics while I tune up the engine's timing?
 

jbk

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livingston la.
when you time the engine with the light its at full rated speed 3600 rpm. the tm tells you how to set it up while its off. so get it up to speed right away if you can. you need tm 5-2805-259-14 on the engine. their are some tms on this sight under the resource section at the top of this page. read over these if you can.
 

callbt

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Peoria IL
Hello, yep found the TM a few days ago, didn't find anything about timing while it's off- as in how to position the magneto prior to using the timing light. My old Bug was set with a static light, can't do that here due to the mag flipping around on springs. I had marked the original poistion prior to taking the mag off- it runs but still need to verify with a timing light.

I did note in the TM under carberator settings, that it talks about letting the engine warm up while at idel- did I miss a part that said to unhook any generator connections or is this too general of a TM and doesn't apply to the engines attached to generators?

for now the engine runs on nearly full choke, so the carb isn't as clean as I thought- so that will come off later this week for another cleaning.

found another interesting bit inside the control panel- seems someone CUT out the L1 wire. I think this might of been done to disable the 3 phase to insure that ONLY single phasse operation could be attached- aka not wire the generator up wrong.

the circuit breakers will take some research too.. why three wires to each breaker? Might have to call in some EE friends.
 

callbt

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Peoria IL
Hello, I had the engine running, still on 2/3 choke. I wanted to regap the points, so I pulled the mag, set the points to 0.015" put it all back together, no spark ... hmm took the mag back off to trouble shoot.

Should the wire coming from the "coil" be grounded when I check with an ohm meter?

I've got a working timing light, so once I get spark again, I'll be able to set the mag and get working on the EE side.
 

jbk

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livingston la.
did you line up the mag. timming mark to the camshaft gear timming mark? do you have the engine manual? i sent you a pm from me with the link to the engine manual? on page 4-43 mag. istall.
 

callbt

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Peoria IL
yep, lined up the timing marks/lines.. got the manuals, though I"m still at a lost for getting close in the static state, or do I simply use the timing light while cranking- I suppose there is no timing change per speed as with the old bug, so that might work too..
 

liftman

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Central RI
Be sure to have timing marks lined up properly and set the mag into place with the impulse coupling wound up. Bolt the mag in place and leave slightly loose so the housing can be turned.

With the crank timing mark on TDC, turn the mag until the impulse coupling just snaps. The ignition timing will then be set and the timing light is not needed.
 
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