Sam
Hey Guy's
Sam here. Went to fire up the Gen. set today and it was a no-go. Hit the manual switch and it spun over fine but no engine run. Spec, 2004 47220, 15kw 1.5 litre water cooled. 280 Hrs. Just had it running about a week and a half ago and it ran fine for 20 min. Have no idea why it quit today. One of life's great mysteries maybe. Went through the diagnostic tests in the flow chart of the factory manual. Have fuel, no malfunction lights and it appears also no fire. Traced it all the way up to wire 14@ the distributor. Wire 14 gave no voltage to the distributor while manually cranking the engine so it sort of looks like I will be replacing the board. Hate that, its my second one since 2004. Here's my real question: while on a website regarding logic replacement they are also recommending replacement of the Filter Capacitor (0A3968) and the Diode Suppression Pack that has 3 diodes in it (070882) at the same time. I have never replaced either piece in the time we have had this unit. I looked on the wiring diagram and both are tied into the start and run and charge circuit involving wires 14, 56 and 150. Does anyone here with more electrical engineer experience than me have any thoughts as to whether this is a good idea to replace, bad idea and leave them alone, or a way to isolate the pieces by pulling them out and manually test them to see if replacement is really necessary. From my perspective the pieces are not real expensive, ( both under 100 dollars each) and I will definitely replace if you think it is a good idea to save possible future Logic Board damage. Both pieces come with the open end connector already attached so all I have to do is remove the existing piece and reconnect the new in it's place. At the same time I don't want to spend money needlessly by just replacing good parts. You guys have always bailed me out before so hopin you can tell me what I should do here. Thanx all, Sam
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Peddler
I have never replaced the suppressor pack on these though it could be a problem.  It is there to suppress flashback from the collapsing magnetic field from the fuel solenoid and the starter which could damage the board.  I don't see how your situation could be a bad board as you say you have fuel which is the #14 wire. The distributor #14 wire originate on the same pin as the fuel I think though I would have to look at a schematic, if you have one you should have the other.
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murphy
Capacitors do fail.  I check the one in my A/C compressor every year.  The last time it was replaced it had dropped from 45 mfd to 0.7 mfd.  Do you have a meter that can measure capacitance?
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Sam
Regarding the no start, Peddler, you are absolutely correct. I checked the schematic and wire 14 comes off the terminal strip 1 with 3 wires going to the engine connection bulkhead and from there in the engine compartment to the gas solenoid, voltage regulator and live voltage for the distributor. I think in my haste last night in the cold with the wind setting my hair on fire I did not get a good read on the distributor. That happens when you are trying to do 3 things with 2 hands. I can tell you that this morning in the light as I sat looking at the engine compartment I looked down at the high pressure reduction regulator and the top vent was once again "daubered" shut with MUD! I cleaned the top and bottom of the regulator again and hit the manual start button and it fired right up. Haste makes waste, right? I am thinking that I will take a piece of aluminum screen and cut it to fit the regulator by wrapping it all the way around the regulator and pull it tight. I will then secure it top and bottom with zip ties to keep these miserable little somebodies with wings off my pressure regulator since they are intent on making themselves a source of my aggravation. With the run issue solved do you guys think it would hurt anything to replace the diode pack and the capacitor say just as regular maint.? They are original to the unit manufactured in 2004. I have 280 hours total with probably 180-200  hrs run under load. What say you? Thanks guys, Nate 
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Peddler
It won't hurt anything but I am not sure it will help either.
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Sam
Murphy,
I do not have a capacitance meter. I only have a Craftsman Digital Multimeter Model 82082. It only checks AC-DC current and Ohm's. I don't think it will do capacitance? Can you recommend a meter and approx. cost? Also I have never checked a capacitor for value before, so I am in new skill territory here. Want to learn though. I know we are checking micro farids value and I guess that should coincide with what is stamped on the capacitor cover? How much of a variance can there be in values and it still be good? Will I have to remove the capacitor to check it's value or can I leave it hooked up? Also do you happen to know the value 0A3968 should display? Any guidance here for the uninformed is deeply appreciated. Thanx guys, Sam  
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Sam
Murphy,
Just checked downstairs and have an Ideal 61-702 200 amp clamp meter that checks capacitance to 200 MFD. That should do it, right? Let me know, thanx, Sam
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murphy
I would not expect anything to be that high.  As I said the capacitor for my air conditioner is 45 mfd for the compressor and 5 mfd for the fan.  Those type of capacitors typically have a 20% tolerance.  Usually the value and the tolerance are on the side of the capacitor.  You are looking for big changes or a bulged or split case.  It will have to be disconnected to measure it.  Otherwise the connected circuitry would affect the reading.  I can't answer the question about 0A3968.  I am not a Generac tech but I am a retired electrical engineer.  I have a dedicated capacitance meter, A BK Precision model 810C.  The smallest scale is 200 picofarad and the largest scale is 20 millifarad.
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Ron Goldstein Rongold
One recommendation before you check any capacitor----Discharge it first. Large capacity capacitors can and do hold a charge even after they are disconnected and can destroy your measuring equipment and can give you a good shock. Take the capacitor out of the circuit and short across its terminals to discharge it.
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UPS
Basic measurements of capacitance value don't necessarily show the whole story.  There is also ESR (Equivalent Series Resistance), only measured by meters intended for that purpose.  Old capacitors tend to develop high ESR making the measured capacitance unimportant.  If not expensive or difficult, just replacing it is often best.
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Sam
Before I take it out I will shut down the gen. @the auto transfer switch, take out the panel fuse and disconnect the battery to kill all voltage in the system. Ron, I watched a video and they showed the same thing, discharging the capacitor before touching any instrument to it. Agree that is important and would save my Ideal 61-702 from damage. I just want to see what it is showing. UPS, I am thinking about replacing anyway. As far as difficulty it is wired to the TS1 strip in spot 0 and 14 with both ends using a spade connector. Difficulty replacing about a 1 on scale of 1-10. It runs about $68.00 which is pretty expensive for a single wire capacitor, but hey it's generac were dealing with here. Everything's plated in gold. Hey, Peddler, Murphy, Ron, UPS thanks guys so much for all the info. What a wealth of knowledge on here. Sam
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