Exercsing the Genset

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John From Detroit

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In days of old when folks were bold and we were still on a different host.  This topic stired up some serious conservation.

I now have 3 generators, 1: Genrac (Briggs & Stratton) 1KW  #2:"Generic brand" "Contractor's grade" 3.7KW and #3, a brand new Onan Emeralg Gold, roughly 7KW  (nice not so little unit, I'm glad it's auto-portable or is that auto-mobile, as it's in the gnerator bay of a much larger vehicle which is (no surprise) not exactly as advertised)

The Gernac manual said to run it once a month to maintina the rotator's magnetic properties (Which I do admit seemed strange to me, however the generator did work much better once it had worked and worked, and worked some,  That is, gas tank full #2)

Here is a quote from my ONAN manual

Exercising the Genset:

Exercise the genset at least 1 hour each month if use is infrequent. Run the genset at approximately 1/2 the ratedd power. See LOADING THE GENSET (page 9). A single exercise period is better than several shorter periods.

Exercising a genset drives off moisture, re-lubricates the engine, replaces stale fuel in the fuel lines and carburetor and removes oxides from electrical contacts and generator. Te result is better starting, more reliable operation and longer engine life.

[end quote]

This is straight from the manual,,, Which I'm busy reading,  Nice generator by the way
 

Tom

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That's been pretty much the standard advice from generator manufacturers for a long time. I must admit that I rarely follow that advice though.
 

Ron

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Exercising the genset is more important with gas powered gensets that with diesel or propane due to the varnish buildup that is more prevalent with gasoline.  Like Tom mentioned this recommendation is pretty much standard.  According to a Onan mechanic the most common cause of generator failure is carberator fowling due to varnish buildup from stale gas.  One thing that will help is to run a fuel stabilizer through the fuel tank and run the genset to insure the treated gasoline reached the genset carburetor.
 

Tom

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Hey Ron, just noticed the new (?) tag line:

The man who coined the phrase, Money Can't Buy Happiness, never bought himself a good fly rod !"

Pretty neat.
 

Jim Dick

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John,

It certainly is a good idea to run the genset occasionally. I have been told if you do not run it a minimum number of hours as suggested by Onan, and you have problems while still under warranty, they may not fix it for free. Not running it is not maintaining it properly.

 

Phil

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John In Detroit said:
In days of old when folks were bold and we were still on a different host.  This topic stired up some serious conservation.

John, it will probably stir up some interest now also.  :)

I have a standby generator at my house that runs on natural gas.  It has a computer control built in that runs the generator for 12 minutes once a week.  Both the Generac and Onan home systems use the same 12 minutes per week exercise standard.

Phil
 

Alaskansnowbirds

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Ron said:
Exercising the genset is more important with gas powered gensets that with diesel or propane due to the varnish buildup that is more prevalent with gasoline.? Like Tom mentioned this recommendation is pretty much standard.? According to a Onan mechanic the most common cause of generator failure is carberator fowling due to varnish buildup from stale gas.? One thing that will help is to run a fuel stabilizer through the fuel tank and run the genset to insure the treated gasoline reached the genset carburetor.

Everyone talks about exercising a genset from the stand point of the engine. It is just as important to exercising the genset for the good of the generator also. Some generators will lose their stator charge if not run for a long time. A generator I had for standby power in Alaska would do that. Took it to a dealer once to get the stator "flashed". He was kind enough to show me how to do it so after that I just did it myself.

 

Tom

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Alaskansnowbirds said:
Some generators will lose their stator charge if not run for a long time.

Don, that's the reason I used to see/hear for running the gen set under load periodically. OTOH I've let geneators sit for 6-12 months and they'd fire right up with no apparent problems.
 

Alaskansnowbirds

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Tom said:
Don, that's the reason I used to see/hear for running the gen set under load periodically. OTOH I've let geneators sit for 6-12 months and they'd fire right up with no apparent problems.

Tom,

I never did figure out any time frame on when mine would lose its charge. I left it set for over two years once and it fired right up and came on line. The only thing I can figure out is it may have something to do with where the rotor stops in relation to stator.

 

Smoky

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Re Ron's new tag.  I am wondering if I will be able to use my 8 wieght Sage?  I bought it for horsing around sal****er stripers.  Now I wish I had bought a 4 or a 5.  :(
 

Tom

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Alaskansnowbirds said:
The only thing I can figure out is it may have something to do with where the rotor stops in relation to stator.

Not sure I understand that Don, since the rotor will be turned by the engine as soon as it is cranked. I seem to recall that ferro mangets can lose their magnetism with prolonged exposure to heat, but I've stored them here in the summer in CA.
 

Alaskansnowbirds

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Tom said:
Not sure I understand that Don, since the rotor will be turned by the engine as soon as it is cranked. I seem to recall that ferro mangets can lose their magnetism with prolonged exposure to heat, but I've stored them here in the summer in CA.

Tom,

Like I said, I never did figure out a reason why sometimes the magnuts would lose their magnetism and other times they wouldn't.  :( :(

 

Karl

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'Flashing' a generator was common and necessary with automotive generators (NOT alternators) back in the old days when installing a new one, as the rotor didn't have any residual magnetism. Newer gensets (alternators) use ceramic magnets that do not require flashing; if fact you can cause more harm than good. The main reasons for running one regularly is to replace the stale fuel AND to keep the slip rings free of corrosion. Merely running one for 15 or 30 minutes is not enough; it must be under a pretty good size load like an A/C or microwave. This is true if it's gasoline, diesel or natural gas or propane powered.
 

Pat

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Sometimes the problem with starting a generator isn't the generator, but the house batteries required to fire it up.  I have had to boost my generator from the motorhome motor to get it started when I was having battery charge problems. 

I have been in RV service shops where people are having generators replaced, ostensibly because they failed to do the monthly maintenance run.  I think dealers should make this information a top priority when doing a walkthrus with new buyers.  Maybe they should have a form buyers sign that buyers have been advised.  If the dealer can't produce the form when the generator dies, the dealer gets to pay for a new generator.  I was never told about this with either motorhome, and, no, I didn't focus on it when reading the manuals.  And we won't even go into the myriad of used RVs that come without manuals.  Heck, new RVs rarely have all the manuals.  I've had to acquire several from the manufacturers.    Based on some comments here that some people ignore the monthly maintenance run and still have no problems starting their generators, I suspect this maintenance step is a handy copout for Onan for any generator that goes bad.  They have figured out that people read the manual only when something goes wrong, so they inserted a frequent maintenance requirement that many rarely know about to perform, thus providing Onan with warranty-free sales.

--pat

 

Karl

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Pat,

All that checklist would do is give the dealer and the mfg's an out; not the buyer. All they would have to do is pull out their copy (and you can bet they will have it) and point to your signature and say "See, we covered all those items and they signed it indicating that they understood everything." There are so many systems, control units, operating and maintenance procedures, and just plain common sense items that would have to be covered by the 'walk-thru', that it would take days, if not weeks to accomplish fully, and no dealer or mfg. (let alone the buyer) would be willing or have the resources to spend that much time to make sure each and every item is fully understood; and that assumes the dealer/mfg. has that level of understanding themselves! With an auto, you wouldn't let it go for a year without changing the oil and filters, checking tire pressures and wear, and other standard maintenance checks, and  a MH is far more complex than a car. The only good solution to avoiding problems is to have a comprehensive checklist and then follow it. We all have or should have such a list for checking pre-departure items; so should we have one for MH periodic maintenance items/procedures. Bottom line is RTFM's and create your own checklist based on your installed equipment and usage patterns. You can't make someone else responsible for your lack of proper maintenance. Out-of-warranty MH's and systems create an even greater demand for diligence on your part and repair insurance is, IMHO, a necessity, not a luxury. Either way, a breakdown of anything, covered or not, can really screw up your best laid plans for a great time on the road, and it's no fun to kick yourself in the backside for neglecting to check the oil level in the genset.
 

Pat

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Karl:  I guess I still remember the little old couple who had to buy a new generator who had no clue about exercising the thing.  They were pretty sad.  I know a fairly RV literate person who had no idea he had to exercise it, and I have run into people in campgrounds who aren't aware of the requirement.  I think I got lucky and read it in a magazine somewhere by the time I got my current motorhome. 

I wasn't referring to a checklist with a zillion things on it.  I was referring to a single generator form.  I know, I know, people are stupid.  People should take control of their lives and their expensive RVs.  Etc. But there is no denying that this generator exercise issue is way too common to be passed off as owner negligence.  If I were an honest manufacturer, I wouldn't  just sit on my hands and enjoy watching too many people void the warranty on my equipment so I can unload replacements on them. 

As for a maintenance checklist, neither of my units came with one.  For the money these things cost, they should have comprehensive and complete custom checklists that apply to the SPECIFIC units and not some general thing that sounds like a telephone answering system:  Do this if you have model A, do this if you have model B, do this if you have model C, and by the way, the model number is buried under the fittings where you can't see it.  Assuming you have one of those in your rig in the first place.

Don't even get me started on the erroneous information I have been given over the years.  Although I started RVing as an ignorant female, I'm more than willing to take care of my motorhome, since it represents all I have, but when somebody tells me to do exactly the wrong thing, I (1) damage the part or system and (2) have to unlearn the false information and (3) have to learn the true information.  I've been through an awful lot in the 4 or 5 years I've owned motorhomes.  What I find sad is that the community has to develop forums and help sites (for those lucky enough to have access to the internet) to make up for the incredibly bad or nonexistent information from the factories and dealerships.

And manuals.  My hot water tank shows how to check for or service something, and it has a partial drawing of a very small section of the unit with absolutely no indication of its relative location on the unit as a whole.  I have no clue how to find the darn tube, or whatever it was.  Actually, I think Gary explained where to find it once.  The hot water tank people should be paying him for doing their job.

--pat
 

Karl

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Pat,

I agree totally that missing information or mis-information is the cause of much trouble. Hopefully, this forum helps solve some of that based on model-specific information; either thru owner manuals or personal experience.

create your own checklist based on your installed equipment and usage patterns.

Information on almost any piece of equipment is available either here or with a Google search. Manufacturers, especially reputable ones, have them on their websites for download, usually in PDF format. Fortunately, the previous owner of my coach kept every manual, label, tag, etc. for every piece of equipment, accessory, and furniture, so my job was quite easy. The Onan manual devotes 2 full pages to genset breakin, exercise, and storage, and explains the reason(s) why it's so important. Quote from Onan Operators Manual: "If use is infrequent the genset should be exercised at least 2 hours each month at approximately 1/2 rated power. See Powering Equipment. Exercising the genset drives off moisture, re-lubricates the engine, replaces the stale fuel in the fuel lines and carburetor with fresh fuel and removes oxide from electrical contacts and generator slip rings, thereby promoting better starting, more reliable operation and longer engine life. A single two hour exercise period is better than several shorter periods. See STORAGE as an alternative if it is impractical to have someone exercise the genset on a regular basis." 

And manuals.  My hot water tank shows how to check for or service something, and it has a partial drawing of a very small section of the unit with absolutely no indication of its relative location on the unit as a whole.  I have no clue how to find the darn tube, or whatever it was.

Good point. The other day I was going to change the antifreeze in my toad but couldn't locate the drain petcock on the radiator no matter how hard I looked and felt around. Finally pulled out the shop service manual where it explained that you have to jack up the car and remove a plug from the rear bank of cylinders of the motor. Had I not sprung for the $65 manual, I still would be looking! :-\

 

Pat

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Karl:  I have all my manuals sorted by chassis and coach related equipment.  Two huge zippered envelopes.  The house stuff is separated in labeled gallon freezer bags by category like kitchen, water, electric, etc.  Every major receipt is attached to the manual.  (I'm going to have to change my credit card if I ever sell this place.)  Within each category bag, every item with multiple papes, parts, or other attachments is accumulatd in its own plastic bag.  I have acquired some of the manuals that I'm missing.  Some I had to download, but they're all in the same Manuals computer file for the RV.

Still, with all that info, there is so much I don't know.  For one thing, the basic RV manual is extremely spotty.  The couple schematics are barely legible xerox copies.  One has the on and off sides of a spigot both labeled "on" or something like that.  Other sections, such as "how to clean upholstery" say no more than, "The upholstery needs to be kept clean using normal cleaning methods."  Period. 

I have many decades of catching up to do when it comes to mechanical knowledge.  My folks had to hide tools from my older  brother as soon as he could crawl to things to take them apart.  I remember the day they came home from work to find the big console radio spread all over the back porch.  And he couldn't seem to explain to them why he took it apart.  But, like the rest of you guys, now he has so much knowledge that all of you think is innate, but is mostly a lifetime of learning.  In 8th grade I had to fight to be allowed to take mechanical drawing instead of cooking or (gag) sewing.  I think they just let me do it in the misguided hope that it would encourage me to behave.

--pat
 

Tom

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Pat said:
The couple schematics are barely legible xerox copies.

Pat, I also couldn't read the small, poor copies of schematics in my owners manual. While I was at the Monaco factory I requested and received large, legible schematics for my coach.
 
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