Generac generator won't shut off with switch

Okay I will see if I can find the model number and such. Should I start a new post about it?

I guess it would depend on the model but it may have a thermocouple which sticks out into the flame. As it fires up the thermocouple senses the flame and lets the gas valve know that it's ok to turn on. Some thermocouples can be cleaned off so they will work again. Get the model number off it and post on here and you will get a bunch of replies. Some of these guys are frig experts.

Sometimes I use the primer, fingers crossed this gremlin doesn't come back. Least I know exactly were to go if the issue does arise again. Do you happen to know anything about the domestic brand refrigerators? I have one that does not want to run off of propane. It works great other then that. It seems to ignite and burn for maybe 30 seconds then throws the check light and goes off. Also even after it seems to ignite, it will still make the clicking sound like it's trying to ignite. But I'm pretty sure it is infact burning and I hear the flame as it ignites. Now this is something I am clue less on. Good thing it's not that big of a issue for us and how we use the camper. But still would be nice to get it all working correctly. Thanks for everything, you have been a very big help!

Fantastic. You've got it fixed.

You do not need a new board. The connections were probably just dirty. Mexicowander has talked about a product that is good for cleaning connections. Either search his posts or perhaps he will tell the name of the product. It's not regular old contact cleaner.

Do not, scrub anything with a wire bristle brush as you may short to other pin sockets. Be very gentle in there or you will create other problems. Be sure of the connector position when you put it back on as you could fold the delicate pins over. Sorry to sound like that but I have seen to may bad things.

Yes, it's probably rubber mounted for vibration dampening so it will shake. Do you use the primer when starting? Or at least when starting cold. Propane may stutter and shake on start up a little more than gas.

Okay I found the board and it is very similar if not the same. I simple unplugged the long white connector and then plugged it back in, and now it will start and kill with all switches. Let me ask you this, should I replace the board at this time or no. Reason I ask is this has been a on going issue, were it will work fine for a few months and then just stop working. I just now have had time to actually mess with it trying to find the issue. Do you think it's a issue in the board it self or just the connection? Upon startup the generator shakes around pretty good and I think that may play a big roll in the connection lose. Guess I'm asking should I just roll the dice and leave it alone, or dig further in. I know it's at the board connection. So that more then I knew yesterday and without your help would still be scratching my head.

I've took the covers off, I will go see if I see anything that looks like that. What I have saw so far just looks like a typical green mother board style. Kinda like you would see in electronics and computers etc. I'm not positive that I'm following you on how to test to see if 18 is grounding or not. You said to not use a test light? So can you please go in a more detail as to the steps to take. I have test lights, multi meters and so forth. My father also has a power probe setup that I could use if needed. But I'm not sure it would help any since it's exactly as it sounds a power probe. I will report back in a bit as to if I can find the board in the above link. Thanks again

803-4 parts manual

Have not found the service manual yet.

If you see the control board it should look like this and it appears to have a 15 slot connector.

Board

Several model seem to use this board

You're welcome.

Not finding that model yet. Best guess so far is to consider it close to a 36lp.

Remove the connectors from the card
If you find the 18 wire, it should be a negative when you hold the switch to stop. It may be best to remove battery power. Use a digital meter and dont put any power in the card. Dont use a battery powered continuity light as even 3 volts positive may harm the card.

If it's not seeing it at the card, you found the problem.

Okay got few more numbers off gen set.
Model number 00803-4
Serial number 3116036
kW rating 3400
Rated voltage 120
Phase 1
Hertz 60

I know you don't need all that info, but figured I would go ahead and list it. I'm going to remove few covers and do a visual inspection of the wiring and all connections. Thanks a ton for your help!

I cant tell exactly which wiring diagram to use without the full model number. There should be a model number and serial number on an engine tag. Generac uses common wire numbers and methods across the product line. There appear to be 2 wiring/ignition systems used on the 34lp models.

In this service manual, on page 91 you will see the start stop circuits. Locate the remote switch, main switch, wire 14, wire 18 and the negative that is common to both switches. I dont know if you have ever worked with this stuff before but to the new person they usually go cross eyed at first sight. Look it over several times and it will all pop out at you.

On page 92 you will find system operation. This is an Impact 36

generac


When you push start, a negative is sent to the control card and a positive is then sent from the card to the ignition module and fuel valve. It remains there unless the card sees a negative from the low oil pressure or high temp switches.

When you push stop, wire 18 sends a negative to the card and the card removes power from wire 14 and the ignition system stops.

On one of the other wiring diagrams when doing the same things I just described, the stop function happens when the card sends a negative to the module and "grounds" the module/coil. I will post a link at the bottom for that schematic. Right now we will stay with the "powered" ignition schematic.

So the 2 systems are common in the way the main switch and the remote switch are wired. Both systems send a negative to the card to tell it to stop.

If you look at the schematic you will see that the main switch and the remote switch panel merely piggy back each other.

What this is telling us so far is that we know we have a negative all the time at main switch and remote switch or we wouldn't be able to start the engine. Again, a negative is used to both start and stop the engine. We have it to start so we have it to stop it.

The question is where did we lose the signal that goes to the card or is the card seeing the negative signal yet not processing it to either drop the positive for the one type of ign system or not ground the other type of ign system.

Since neither switch will kill the engine we would first look for an open in wire 18 between the main switch and the pc board. Wire 18 should go to pin number 4 of the 10 pin connector.

On page 3 of this link they show a whole list of specific model.
On page 72 of this manual it does show a grounded type ignition system and a different control board.


Gen

SO......look this stuff over and you will get the general idea of what we are going after. We have not nailed the exact schematic by complete model number but I would guess that it's like the top link np36.

You can do a visual examination of your unit and see if there is a loose or broken wire from the main switch to the card but before we start probing any wires we need to know exactly which schematic to look at. The pins could be loose in the connector also.