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GP17500E Boggs down with load

Posted: Thu Feb 25, 2021 9:05 pm
by Brewerbo
My GP17500E has 5 hours on it. Serial # 3001700513 - Model # G0057352. It needs to be choked to start, which seems normal. But it needs choke to restart when it’s warm. It can handle normal loads without bogging down. But when a 220V load kicks in, like the water heater or AC unit, the engine dies, unless I’m standing right there and work the choke until the engine stabilizes. Then it runs fine with heavy loads, until another 200v load kicks in.
Also, the “Idle Control” does not work.
It had non-ethanol fuel with stabilizer in it for about a year. I drained that fuel and cleaned the carburetor. The fuel is now fresh with stabilizer in it. The filter is clean. The fuel pump works. Engine still needs to be choked whether cold or hot and shuts down with heavy loads. It backfires when shutting down.
The generator puts out good power at 60 hertz.
Someone told me that these carburetors are crap and can’t be cleaned, but should just be replaced. What am I missing?

Re: GP17500E Boggs down with load

Posted: Mon Mar 15, 2021 11:55 am
by Bassguitarist1985
It's time for a leak down test if you are 100% sure that the carburetor is clean. Chances are might be some issues going on with the valves. Backfiring while shutting down indicates a rich mixture or a carboned up combustion chamber where remaining fuel from the engine spinning down ignites inside the combustion chamber at a hotspot or in the muffler. I have seen these machines with leaky valves that require pulling both heads and doing a complete valve job.

The other part I've seen go in a short amount of time are the stepper motors that control the idle because the inside gears are made of plastic and they tend to fail. The idle control board can also go as well especially if the battery is not holding a charge. Many variables but I would focus on the gas engine first before looking at anything electrical.

Re: GP17500E Boggs down with load

Posted: Fri Apr 30, 2021 10:47 am
by Ray2020
I am experiencing a bogging issue as well.

I have a Generac GP17500e
Serial# 6437537
Model# 0057531
Current Usage: 32hrs

Usage Background - The generator has sat for about 18months. When it was last run, I ran it until to let the fuel run dry and shut off the fuel line and stored for next use.

Prior to starting - I drained the old gas added new fuel and installed a charged battery. It’s starts and runs fine.

The issue - The main symptom occurs when an appliance such as ac, coffee maker, or the fridge are power on, the generator bogs down momentarily.

Clarifying Example: If the coffee maker cycles on the generator will bog down for 1second or 2, then rpms come back up, but stay lower while the load (the coffee maker) is operating.

This to me would seem like normal operation. However, the generator never bogged down under the same operating conditions before.

Any advise would be greatly appreciated

Re: GP17500E Boggs down with load

Posted: Fri Apr 30, 2021 11:42 am
by Chris
I would start with fuel issues or a blocked carb. Our gas is junk these days and even running until it stops can leave behind gunk.

A coffee maker shouldn't even phase a generator that big!

Re: GP17500E Boggs down with load

Posted: Fri Apr 30, 2021 12:27 pm
by Bigenner
I attached a drain hose to the float bowl on mine to make it convenient to drain the float bowl completely after a run. A long screwdriver easily reaches the drain screw. I only use treated, non-ethanol unleaded in any of my small engines and powersports. Go to pure-gas.org to find available stations in your state.

If you take the 2bbl carb down it's a good idea to keep the left and right jetting components separate. The main jets in mine were different sizes which is fairly common on v-twin engines and in motorcycles. If the jets get mixed up it may not run perfect after you're done. I wrote down and took pics of where everything went during the overhaul. The only parts available from Generac are the float, needle and pin and gaskets and o-rings so you have to take great care or you can get a new carburetor but they aren't cheap.

Re: GP17500E Boggs down with load

Posted: Fri Apr 30, 2021 1:10 pm
by Ray2020
Chris and Bigenner,

Thanks for the suggestions! Glad to hear I wasn’t losing my mind that a coffee maker would cause it to bog down.

I did run 5 gallons of premium. There are a few non-ethanol stations nearby.

Chris,

Where do you recommend I start?
- My tentative plan is to check the fuel filter (float bowl) and make sure it isn’t obstructed. Would the next step be to clean the carbs?

Re: GP17500E Boggs down with load

Posted: Fri Apr 30, 2021 2:43 pm
by Bigenner
As Chris alluded to the carburetor needs to be removed,and cleaned. Preferably in a 40khz ultrasonic tank in a water soluble detergent that won't react to aluminum like Simple Green ProHD and distilled water maintained at 165*F. I like to disassemble as much as possible for a deep clean. Then reassembled with a Generac float and gasket kit. The left and right jetting should be kept separate. If you are not comfortable with servicing a carburetor Chris can source a new carb for you that is a direct bolt-on deal.

Re: GP17500E Boggs down with load

Posted: Tue May 04, 2021 10:31 am
by Ray2020
I am back at it!

Update Replaced the fuel filter and pump. That seemed to help. I still get a slight load rpm change when I turn on the microwave or coffee maker.

I adjusted the throttle a quarter turn. After doing so, during operation the generator shut down. It did start and run fine after I adjusted the rpms back.

New symptoms: prior to my throttle adjustment.
- The idle adjustment is not working properly. It will not increase the rpms under a load.
- Any ideas on possible causes? I am guessing the pcb or stepper motor.

Possible Next Steps:

New Carb install, adjust idle to 120v@60hz, test for load, install new stepper motor if that doesn’t fix it then new pcb.

I am open to any other suggestions.

Re: GP17500E Boggs down with load

Posted: Wed May 05, 2021 8:48 am
by Chris
I think I'm confused about the adjustments... These units use a stepper motor to adjust engine speed. There are no manual adjustments available to modify engine speed. What did you adjust that seemed to make a difference?

Re: GP17500E Boggs down with load

Posted: Thu May 06, 2021 8:56 pm
by Ray2020
Chris,

There is a Phillips screw next to the stepper motor that you can adjust the idle speed. I may not be using the right terminology.

I was able to test the the voltage and it is between 59.8 -60.2hz at 248v

It maintains fine as long as the idle control switch is not engaged.

When the idle switch is engaged it do not bring up the rpms under load.

What is the voltage/hz reading supposed to be when the switch is engaged with no load?

I am guessing that I need to replace the PCB board...