Generac Generator

[lefty2cox]

I have this generator. MF6500
Model: 01006-1
Engine Ident: EHF-00958-2
Frankly, the best luck I've had so far is searching this number on a sticker on the recoil starter: GN 360.

Came in with the usual no start, filthy carb scenario. I cleaned it well, including a trip through the ultrasonic. Everything seems to run great except for the idle control feature. When engaged, the engine stalls. There's an idle adjustment screw on the carb but I was researching and found a video adjusting the low idle speed on the low idle control. This is my first with this feature so I'm not sure how to attack it. Do I want to adjust at the carb or do I fiddle with the low idle control mechanism? It would help if I knew how that works. Is it proximity driven or magnetic? Or neither? I'm just guessing at this point.

Thank you.

 

[Scrubcadet10]

My first thought would be to adjust the idle screw, but one question, does it die quickly,like as soon as you press the button or does it take awhile to die with drops in RPM?
and one thing i would try is if it's a manual choke, try closing it 1/4 to 1/2 way to see if it will still run. if it runs better with the choke, still a carb issue.

 

[Rivets]

You need to adjust the carb idle speed first before trying to to adjusting the low idle control. Before that you need to make sure that your output is 118-121 VAC, plus you have 59.25-60.5 Hertz. You need to adjust your governed top speed under load to get this. If you are outside these ranges you may result in burning up equipment. After I have done this I adjust the idle speed to 2000 RPMs and then test my low idle control. If it stays running I lower my idle by 100 RPMs and test again. I repeat this step down to 1250 RPMs. When I reach this point I double check my load Voltage and Hertz, as they may change, due to how the idle circuit is working. Load Voltage and Hertz are more important than idle speed.

 

[lefty2cox]

Thank you Rivits. I'll check all that.

Scrub, It doesn't die right away. Once the idle control actually kicks in, the RPM's drop down and then it behaves as if the idle is set too low...kind of starts chugging at low RPM and dies. I'll try 1/2 choke at idle to see if maybe I didn't do a good enough job on the carb. I went at it twice but it was pretty dirty.

I actually had purchased a new one but it didn't fit. The fuel inlet, which is a metal elbow running 45 degrees to the carb's equator, was only running at about 30 degrees causing it to interfere with the recoil starter housing. Frustrated, I just decided to clean the OEM again. Maybe I should take another shot at a carb.

 

[Hammermechanicman]

There are a couple different no load idle controls on generators. Some use a solenoid to pull linkage back to the idle stop on the carb. Fire up the generator and manually hold the throttle against the idle stop. Does the engine surge? If yes carb idle circuit needs cleaned. Does it idle smooth but too slow and die? Bump up the idle to spec. Assuming it is not an inverter generator if it runs at proper frequency at full electrical load i would not mess with the govenor linkage and control unless you have a shop manual for it. Some of the auto idle linkage can be very sensitive to adjustments.
Got a pic of the engine?

 

[lefty2cox]

I'll try that as well. This is not my specific generator as I'm not with it right now but this is the identical model. The yellow arrow is pointing to what I think is a solenoid type idle control.

 

[lefty2cox]

How does the idle control work? Should it be sucking that linkage all the way in? Or should it be farther away from the field and only be drawn closer. It seems to be at odds with the idle screw on the carb. I think it's because it's too close to the lever it's acting on. Should it be bottoming out on that bolt head when engaged or just drawn towards it?

A quarter turn seems to put me on either side of where I want to be with RPM. I'm either idling at 2900 or 1300. The idle screw on the arb is turned all the way in. The spring on that screw is fully compressed.

The owner of this told me he picked it up used and the idle control has never worked since he's had it. He says it would just stall when engaged.

Hope this makes sense
Thanks

 

[Rivets]

Give us a couple of pictures of the control, linkage and carb so we have a better understanding of what you have. With them we can see what you and are talking about, plus I would like to see that the linkages are hooked up correctly.

 

[lefty2cox]

Of course. The first one is the idle control thing. The little nut in the bottom right of the photo is the RPM/Governor adjustment
The 2nd photo is where the linkage connects to the throttle on the carburetor. You'll notice that the linkage passes through the housing via a small 3/8"ish hole. I noticed it was catching and binding on the edge of the hole so I had to bend it a little so it wouldn't drag. This seems to have improved things significantly as far as surging at idle. So as it sits, RPM set to 3600 and idling at about 1900.

I'm planning on going through it now, as you suggested, and testing all of the outputs. I just wanted to understand how to control this thing before trying to dial it in. But I'm still not there. The mechanism is so sensitive to the slightest adjustment. But I did hold it down manually and it runs very smooth at very low RPM so I think we're ok on carb cleanliness.

It also looks like this idle control thing renders the idle adjustment on the carb obsolete. Because it never quite bottoms out on it. The idle control bottoms out before the throttle lever ever hits the idle adjustment screw on the carb. If I adjust the idle control to the point where it allows the idle screw to play along, It's stalling. Which made me think I wasn't getting enough fuel at the top end. But my RPM's are running strong at the top, even under load. Thank you.

 

[Rivets]

To be perfectly honest, with out this unit right in front of me I’m lost as how to tell you how to proceed. First thing I’m seeing is a unit which neither Generac or Briggs say they support and is a clone when Briggs and Generac were trying to work together to enter the generator market. I remember working on them, but also remember that I would get extremely frustrated and would have to get help to get them running correctly. Most of the time it was a trial and error troubleshooting experience. The control unit is an electromagnet units which pulls the linkage closed under no load, current is shutoff to the controller when a load is applied. Instead of one adjustment on the controller, you have two, which I can see in your second picture. If I remember correctly one of these is connected to the governor and the other to the throtitle linkage. You need to adjust both, but I’m sorry I don’t remember the procedure to it, and you are correct, they are very touchy. I’ve looked through all my files and can’t find any literature on this system, but I’ll keep looking. Maybe someone else has some more experience with them.