Generac NP66G Issues

[Bilito]

Originally Posted by Dave78Chief

Could be the float level however I have not found anything that gives any detail about these carburators. You may be stuck with replacing it. You could try Smokstack to see if you can find something - Dave
Generac Generators (SEARS, etc.) - SmokStak

Got the neighbors boat all fixed and running perfect and now, BACK TO MY RV ISSUES
I have changed the rubber fuel lines from where they start on the frame rail all the way to the genny carb. even put in a new genny fuel filter
I have tested the oil pressure and oil temp switch's according to the manual you sent and they test OK
I tested the CR1 and CR2 relays acoording to the manual and they test ok
I pulled the fuel line off at the carb to do the fuel pump test and it squirts fuel out real good
I have rechecked the oil level and it is full
Following the manuals direction I start the genny with the two main breakers off, It starts instantly, runs nice and smooth for 30 to 40 seconds and then just shuts off
I can restart it immediatly after that happens and it does it all over again
This is very frustrating, what else can I do?????
BTW the little red light on the regulator lights up when the genny is running eben tho the main breakers are off, I think this is normal??

[clyon51]

Originally Posted by Bilito

I can restart it immediatly after that happens and it does it all over again
This is very frustrating, what else can I do?????
BTW the little red light on the regulator lights up when the genny is running eben tho the main breakers are off, I think this is normal??

Yes that is normal. It's just letting you know it's producing proper power, it's just not going passed the breakers.

It sure sounds like a float problem to me, as long as you are sure the oil pressure switch is working properly. The float could be sticking or the fuel galley and flow valve is gummed up or has dirt in it. If it were me, I would take the carb off and completely dissemble it. Then with Gumout, clean every part, make sure all the fuel galleys and jets are free from gum/dirt and flows smoothly. Then check float operation to be sure it moves freely with no sticking.

If you tackle this, get the Generac part numbers off of it. Here are a few links for new carbs and re-build kits if you decide to do that.

Generac 0A4600ESRV Carb Rebuilt Kit for A4600 & A6562 : A.S.A.P.

Generac Carburetor 021203 Delorto 190/220

Replacement for Generac RV Carb Rebuild Kit 46042, aftermarket : A.S.A.P.

Generac 0A4600ESRV A4600ESRV Carb Rebuild Kit for A4600 A6562 | eBay

[Bilito]

I had the carb off and disassembled and took it to a friends shop who does Outboard Motors, he soaked it overnight in some commercial type of carb cleaner tank. it came out like new and he blew out all the passages.

As you say it could be the float adjustment, can not find any info what the correct adjustment could be.

My next thought will be to start it up and let it run and wait for it to quit and then give it a squirt of starter fluid to see if it will catch again

what puzzels me is right after it quits, and it stops turning I can start it right back up again

[clyon51]

Yeah, that's a strange one and that sounds like ignition. I know you checked out oil pressure switch, but you might try to bypass it by just connecting the two wires. Then you could totally eliminate that. Another thought, on a generac, you can continously hold the start button after engine starts. Doing so keeps it choked as long as you need to, but there is an rpm sensor that disengages the starter to prevent any damage. I'm thinking the control board may be bad (and I'm guessing here)....continue to hold the start button after it's running. It may just keep running. If it does, you can eliminate the fuel problem as far a float or carb problem. Also while doing that, make sure the choke doesn't kill the engine. A normal start just to watch the choke wouldn't hurt.

I got a bit ahead of myself because I'm thinking and typing out loud in a noisey place on a cell phone but, I'm sure holding the start button also engauges the fuel pump. When running, the rpm is senced and the control board takes over the fuel pump. So if the board is bad it shuts down the pump and the motor runs until the bowl is out of fuel. You could also try holding the prime button down after engine starts rather than start button, either one could give different results. I had a board go bad once and the only problem was the choke wouldn't operate, I kept it for a spare for a major problem. Do you have a Generac TS Guide?

[Bilito]

Originally Posted by clyon51

Yeah, that's a strange one and that sounds like ignition. I know you checked out oil pressure switch, but you might try to bypass it by just connecting the two wires. Then you could totally eliminate that. Another thought, on a generac, you can continously hold the start button after engine starts. Doing so keeps it choked as long as you need to, but there is an rpm sensor that disengages the starter to prevent any damage. I'm thinking the control board may be bad (and I'm guessing here)....continue to hold the start button after it's running. It may just keep running. If it does, you can eliminate the fuel problem as far a float or carb problem. Also while doing that, make sure the choke doesn't kill the engine. A normal start just to watch the choke wouldn't hurt.

I got a bit ahead of myself because I'm thinking and typing out loud in a noisey place on a cell phone but, I'm sure holding the start button also engauges the fuel pump. When running, the rpm is senced and the control board takes over the fuel pump. So if the board is bad it shuts down the pump and the motor runs until the bowl is out of fuel. You could also try holding the prime button down after engine starts rather than start button, either one could give different results. I had a board go bad once and the only problem was the choke wouldn't operate, I kept it for a spare for a major problem. Do you have a Generac TS Guide?

By TS did you mean the trouble shooting guide and diagnostic tests sections 8 and 9? If so I have them

[Bilito]

Originally Posted by Bilito

By TS did you mean the trouble shooting guide and diagnostic tests sections 8 and 9? If so I have them

Here is where I am this morning.
I started the genset up, main fuses off
It ran for almost a minute then it started to quit
I gave it a shot of start fluid
it fired right back up, I could keep it running with shots of fluid
Seems to me I have a fuel issue
I immediatly unscrewed the bowl drian almost no gas came out
it started to rain so I came inside
I have changed all the rubber fuel hose's and filter from the frame rail to the carb, I have cranked the engine with the fuel hose off and had fuel squirting out, I have not checked the fuel lines for the genset coming from the fuel tank to the frame rail line, also I have not run the motor with the fuel line to the carb disconnected and squirting into a BOTTLE
The motor runs great, starts right up,
and I had the carb soaked overnight in a professional carb cleaner
guess I gotta check the lines at the tank and see if fuel is pumping out while motor is running, I guess the motor will run 30-45 seconds on what ever fuel is in the bowl

[Bilito]

Originally Posted by Bilito

Here is where I am this morning.
I started the genset up, main fuses off
It ran for almost a minute then it started to quit
I gave it a shot of start fluid
it fired right back up, I could keep it running with shots of fluid
Seems to me I have a fuel issue
I immediatly unscrewed the bowl drian almost no gas came out
it started to rain so I came inside
I have changed all the rubber fuel hose's and filter from the frame rail to the carb, I have cranked the engine with the fuel hose off and had fuel squirting out, I have not checked the fuel lines for the genset coming from the fuel tank to the frame rail line, also I have not run the motor with the fuel line to the carb disconnected and squirting into a BOTTLE
The motor runs great, starts right up,
and I had the carb soaked overnight in a professional carb cleaner
guess I gotta check the lines at the tank and see if fuel is pumping out while motor is running, I guess the motor will run 30-45 seconds on what ever fuel is in the bowl

I'm working between the rain squalls now and here is something I just tried, I started the genset let it run and just as it started to quit I pressed the starter button in and sure enough in just a few seconds it came back to life, I did this three or four times, what do we suppose is causing this? it seems as if the fuel pump is being turned on and off or it is running intermittanly or failing

[Bilito]

Originally Posted by Bilito

I'm working between the rain squalls now and here is something I just tried, I started the genset let it run and just as it started to quit I pressed the starter button in and sure enough in just a few seconds it came back to life, I did this three or four times, what do we suppose is causing this? it seems as if the fuel pump is being turned on and off or it is running intermittanly or failing

Sorry to drag this out quote by quote but here is what I just did,
Connected a clear hose to the fuel line leading to the carb
opposite end into a jar
hit starter button and fuel pump pumped fuel and engine started on what was in bowl
as soon as I let off the starter button the pump stopped pumping engine ran till bowl was dry
tried it again same result
This next time I held the starter button knowing there was no fuel in the bowl, as long as I held the starter button in fuel was pumping into the jar.
Something is shutting off the fuel pump as soon as the engine starts
what will do that? Pump only works when starter button pressed

[clyon51]

Originally Posted by Bilito

Sorry to drag this out quote by quote but here is what I just did,
Connected a clear hose to the fuel line leading to the carb
opposite end into a jar
hit starter button and fuel pump pumped fuel and engine started on what was in bowl
as soon as I let off the starter button the pump stopped pumping engine ran till bowl was dry
tried it again same result
This next time I held the starter button knowing there was no fuel in the bowl, as long as I held the starter button in fuel was pumping into the jar.
Something is shutting off the fuel pump as soon as the engine starts
what will do that? Pump only works when starter button pressed

Ok, I've read all your new posts. As I said in my last post, when the start button is pressed, that energizes the fuel pump. The fuel pump will remain powered until the button is released.

Under normal conditions, when the engine starts and is running, a sensor tells the control board this. The control board then takes over fuel pump operation. As long as engine is running, the control board keeps the fuel pump energized until manually shut down or runs out of fuel.

So, from what you said, it would appear to me the control board is bad.

If you want, run this experiment. Start genny and DO NOT release start button for at least 2 full minutes or double the time the engine has ran after releasing the start button before.

If it keeps running for 2 minutes or as long as you hold the button down, you know there is no lack of fuel or flow. After you release the button, the genny will quit after the bowl is empty and about the same time frame it has quit before. That tells you the fuel pump is not being powered by the control board. Whether it's bad or has a loose or broken wire on the fuel pump circuit.

I don't have my TS guide handy, but you should be able to confirm this there.

[Dave78Chief]

CR1 Relay is either not energizing, or the contacts are bad inside it, or you still have a wiring error. Refer to pace 22 (pdf page 24) of the service manual link I provided you. CR1 is the RUN relay. CR1 prevents the starter from re-engaging and provides the path for the voltage to the Fuel Pump and Choke Heater coil when you release the start switch. Please note that the relays in that drawing on that page are shown in the condition they would be for the RUN mode, not the at rest (no power applied) condition. Wiring diagrams for this unit are on pages 39 (schematic) and 40 (physical connections) of the manual.

FYI: While there is a Voltage Regulator module and a Choke module in a Generac NP-66, there is no "control board" like used on a Onan generator.

Dave

[Bilito]

Originally Posted by Dave78Chief

CR1 Relay is either not energizing, or the contacts are bad inside it, or you still have a wiring error. Refer to pace 22 (pdf page 24) of the service manual link I provided you. CR1 is the RUN relay. CR1 prevents the starter from re-engaging and provides the path for the voltage to the Fuel Pump and Choke Heater coil when you release the start switch. Please note that the relays in that drawing on that page are shown in the condition they would be for the RUN mode, not the at rest (no power applied) condition. Wiring diagrams for this unit are on pages 39 (schematic) and 40 (physical connections) of the manual.

FYI: While there is a Voltage Regulator module and a Choke module in a Generac NP-66, there is no "control board" like used on a Onan generator.

Dave

Believe it or not, I mistook the CR-2 for the CR-1 becuase the spades on the back are similarly configured, The CR-1 in buried in that control box, I have finally gotten things apart enough so that I can do the diagnostic checks on the CR-1
pic 1 CR-2
pic 2 CR-1
pic 3 Control box

[clyon51]

Originally Posted by Dave78Chief

FYI: While there is a Voltage Regulator module and a Choke module in a Generac NP-66, there is no "control board" like used on a Onan generator.

Dave

Hmmm. I still don't have access to my manuals, but could have swore that the NP series used the same dc powered engine control circuit board as the Q series. If memory serves, the board number is 92234.

[Bilito]

Originally Posted by Bilito

Believe it or not, I mistook the CR-2 for the CR-1 becuase the spades on the back are similarly configured, The CR-1 in buried in that control box, I have finally gotten things apart enough so that I can do the diagnostic checks on the CR-1
pic 1 CR-2
pic 2 CR-1
pic 3 Control box

Did the test (finally) on pg 31 of the CR1 relay both tests on the #15 wire terminal to ground and 56 wire terminal to ground I get batt voltage and I should now test for open or shorted condition, HOW do I do that, I can see the #14 wire from CR-1 brings power to the pump
I can see from the wire diagram the #14 wire goes to a terminal connector to power the pump but I cannot find that connector

[Dave78Chief]

For reference, they show pin orientation on the physical drawing on page 40. CR1 is at the top of the page (they show 2 different possibilities for CR1). Given they used the same colored wire most everywhere, I see they at least printed the wire numbers on them which correlates to the numbers on the wiring diagram. Wire #14 is the feed for the Fuel pump from CR1 pin 7 (Pin 6 on alternate). Wire #15 (CR1 Pin 12 [alternate pin 9?])is the fused source to the relay.

Dave