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Generac Generators (SEARS, etc.) Restoring, maintaining and operating Generac generators.

Generac Generators (SEARS, etc.)

25 KW Generac


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  #1  
Old 03-30-2012, 09:44 AM
Bdgriner Bdgriner is offline
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Default 25 KW Generac

I recently acquired a Generac 25KW Model Number 00609-4 S/N 3048955 standby generator with 285 hours on it and it appears to be manufactured in the early 90s but not sure._ Engine valve cover says TOFAS, block has 91 on it, and a Generac tag that says P/N 97390._ It has been removed from service for approx 1 year._ The machine is in really good shape minus some surface rust on the support frame._ I need advice on the maintenance needed, how to convert it to use LP in the vapor mode, and how to get a service and parts manual for it._ _I have looked extensively on the internet for the manual but have come up short.
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Old 03-30-2012, 04:03 PM
Wayne 440 Wayne 440 is online now
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Default Re: 25 KW Generac

There is a good chance that the engine was made under license from Fiat. I think that set is a 3600RPM 4 cylinder, if so the most relevant advice I have about maintenance is that you will probably spend more time working on it than you will actually using it.
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  #3  
Old 03-30-2012, 07:18 PM
Wayne 440 Wayne 440 is online now
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Default Re: 25 KW Generac

Also FWIW, here http://www.smokstak.com/forum/showpo...7&postcount=10 is a list of some engines used by Generac.
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Old 03-30-2012, 08:19 PM
Bdgriner Bdgriner is offline
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Default Re: 25 KW Generac

From the other post, It's a 1.6 L at 3600 RPM so it looks like a Fiat Engine. I found a drawing that shows how to change from natural gas to LP vapor but I'm not sure what it's wanting me to do. It says "Reverse position of the pressure reduction valve". What does it mean by reverse the position?
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  #5  
Old 03-30-2012, 09:06 PM
Wayne 440 Wayne 440 is online now
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Default Re: 25 KW Generac

Disclaimer- I can't see your set from here, and I am no expert on gaseous fueled sets.

-----------------------------------------------------------------

Some regulators convert from NG to propane by removing a spring and turning them "upside down".
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  #6  
Old 03-30-2012, 09:39 PM
Bdgriner Bdgriner is offline
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Default Re: 25 KW Generac

That explains the drawing. The drawing shows for LP vapor, the pressure reduction valve inverted and says to remove the spring to convert to LP vapor.
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Old 03-30-2012, 10:02 PM
Ed Sparks Ed Sparks is offline
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Default Re: 25 KW Generac

Quote:
Originally Posted by Bdgriner View Post
That explains the drawing. The drawing shows for LP vapor, the pressure reduction valve inverted and says to remove the spring to convert to LP vapor.
PM me with your e-mail & I'll send you the Kohler T-5700 install manual . It has all the gas info you need.
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  #8  
Old 03-31-2012, 01:14 AM
Isaac-1 Isaac-1 is offline
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Default Re: 25 KW Generac

Ed I think you mean TP-5700, it can also be found as a pdf online along with TP-5400 which also contains some good general information.

Ike
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Old 03-31-2012, 09:22 AM
Ed Sparks Ed Sparks is offline
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Default Re: 25 KW Generac

yep: TP-5700 is what I sent him.
It's hard to remember all the numbers when you get old.
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Old 04-02-2012, 07:52 PM
DPeterik DPeterik is offline
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Default Re: 25 KW Generac

Reversing of the pressure reduction valve only is done if you are going to use liquid propane with a vaporizer. Natural gas uses positive pressure. LP vapor is is also considered positive pressure. LP tanks are under pressure. That pressure is reduced to around 10psi. From there it reduced again to 11-14w.c.
At the frame you will have a solenoid shut off. One wire is ground and the other is the 14 wire to engine run circuit. There should be a pipe to the pressure reduction valve. That will step it down and keep it at a constant 5-7w.c for optimal performance. From there it will go to the mixer which is controlled by engine vacuum. The mixer or governor is electronic on this unit and the controller reads frequency not an rpm sensor. Alternator frequency is more accurate, and has a faster response to load variations.
If you need info setting up the unit for LP, let me know.
You can still get parts for these units and some engine parts are still available. Some parts for the engine are no longer available, but may be acquired aftermarket.

I have a lot of these unit still out there and are running fine. If the unit you have was well maintained and stored properly it should operate just fine.

I will try to dig up some old manuals to this and post them.
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Old 04-02-2012, 09:45 PM
Douglas123 Douglas123 is offline
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Smile Re: 25 KW Generac

Look at your regulator real close. Back in early production they used what was called a California epa approved regulator. Look at the top of the tower so to speak. If there is a screw slot cap on top you have an adjustable and flippable regulator. Hopefully the spring is still in the regulator if it is set for propane now. Some folks just flipped the regulator and left the spring in. If the spring is missing you can purchase it seperately. If you have the EPA regulator it will be sealed and painted green for propane and red for natural gas. These regulators are not flippable nor are they interchangeable or not supposed to be adjustable. Posts some pics if you can and hope this info was helpful.

Last edited by Douglas123; 04-02-2012 at 09:47 PM. Reason: did have model and serial # posted
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  #12  
Old 04-03-2012, 04:27 PM
Bdgriner Bdgriner is offline
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Default Re: 25 KW Generac

I'm glad to hear you have seen many of these units still inservice and running fine. I was amazed how clean it was and how it ran when i decided to buy it. I have purchased a Fisher R632 two stage regulator to step down tank pressure to 11' WC input to the 3/4" inlet of the machine. My plan was to remove the spring from the pressure reduction valve and invert so i could use LP vapor. Sounds like it could be more to it. If you could send me more details and a manual, It would be appreciated. I will post some pictures of the regulator also.
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Old 04-03-2012, 04:44 PM
Douglas123 Douglas123 is offline
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Smile Re: 25 KW Generac

I did get a chance to pull up your model in partsmart today. Did NOT show the California epa regulator. does not mean that they actually didn't put one on. Unit was probably built after january 1996. Still very busy here which is good. If no one beats me to the info I will scan an original owners manual and find my old generac engine cd's somewhere in my cluttered home office.
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  #14  
Old 04-03-2012, 08:04 PM
DPeterik DPeterik is offline
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Default Re: 25 KW Generac

Douglas123 brought up a good point that I forgot about the California regulators. These regulators have different orifices. LP orifices are smaller. If you have the silver Maxitrol, I have used them for both. Need to adjust your mixer, probably a Impco model 50. There is a rich lean adjustment. Need to run it leaner than natural gas. I use a gas anaylzer and a load bank to adjust. Since you would not have these, can be done without. Adjust mixer at no load, so that you don't have a strong smell of gas from exhaust. With LP the timing sometimes may need to be slightly adjusted. Bring on some load and check response. Some mixer adjustment may be needed to balance out.
I do have info on this but need to find it. I have done this for so long its natural.

I will post if I find my info.
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  #15  
Old 04-03-2012, 09:47 PM
Bdgriner Bdgriner is offline
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Photo Re: 25 KW Generac

The regulator installed is a gray Maxitrol. I attached 3 pictuires of it. It has been running off of natural gas prior to me obtaining it.
Attached Thumbnails
Fuel Reg Pic 3.jpg   Fuel Reg Pic 2.jpg   Fuel Reg Pic 4.jpg  
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  #16  
Old 04-05-2012, 10:13 PM
Bdgriner Bdgriner is offline
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Default Re: 25 KW Generac

I found these detailed instructions on converting the Maxitrol from natural gas to LP vapor.


For some older Propane vapor powered generators this is sometimes used as a "demand regulator" and mounted at the inlet side of the carburetor:

Remove the cap on the end of the cone & notice the white plastic threaded adjuster that compresses the spring.
Remove the adjuster with a screwdriver & take out the spring.
Turn in the adjuster approx 2/3 - 3/4 of the way down the threaded cone so there is room to store the spring above the adjuster._
Replace the threaded cap at the end of the cone.
The spring is now just in storage and NOT used to regulate pressure, so now instead the regulator controls volume or flow,_ based on engine demand created by vacuum from the engine.
The device must now be positioned with the cone pointed DOWN, so that the internal "valve" will drop down and shut off the fuel until engine demand / vacuum calls for it.
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Old 04-09-2012, 10:53 AM
Bdgriner Bdgriner is offline
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Default Re: 25 KW Generac

Had the first test run with propane vapor yesterday and it started and ran fine. The frequency would start to drift high and all I could do was add about 1.5kw load on it. This would bring the frequency back down. When I removed the small load the frequency would drift high. High is greater than the local meter would indicate of 62hz. Voltage looked great. I did smell just a hint of propane in the exhaust so I may have an adjustment with the crab. Once I can get more load on it, I will adjust the governor per the service manual for speed adjustment and then see if the carb needs adjusting.
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Old 04-09-2012, 08:20 PM
Daverepair Daverepair is offline
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Default Re: 25 KW Generac

If you look at your first photo you will notice a small brass plug next to the cone part. That is a vent to allow atmosphere pressure to the back of the diaphragm that helps control that reg. Remove it and look for spiderwebs and such in there. If clogged it can cause problems. There is one type of spider here in New England that just loves it in there.
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Old 04-19-2012, 04:40 PM
hiboyford hiboyford is offline
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Post Re: 25 KW Generac

Tell me the complete model and serial numbers and I will get you all the manuals for this unit. I have around 100 of these units still in service.
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Old 08-07-2012, 01:18 PM
hiboyford hiboyford is offline
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Post Re: 25 KW Generac

I have the manuals for this unit I think. send me a PM with model and serial # and I will send you what I have. Also the statement about this unit needing more work than you get use out of is False. I have almost a Hundred of these still in service all over the country they are good and reliable if properly maintained. They do over heat and there is a conversion kit that fixes this problem
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