valve adjustment on 2019 9 KW Generac

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Tim F
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I have a 2019 LP Generac 9 kW with 265 hours on it. The model number is G0070291, Serial number 3004790348, Production date 20190722. I use this generator for backup power at my camp in Northern Maine. I do my own oil filter, oil, air filter, and spark plug changes every fall regardless of the hours on the generator. With 173 hours (December 24, 2020) on the generator, I had an fault code E1100. I reached out to someone on the lake who was a local and got a name of a generator mechanic who works on all the generators on the lake. This guy answered my call and asked me if I ever did a valve adjustment on the generator. I said no, but I had read about it in my manual. He said it is a known problem with the 9 KWs and that he would be out to adjust the valve clearance. He charged me $50.00 (that's it) for 15 minutes of work. With 223 hours (October 27, 2021) on the generator I got fault code 1100 again. The guy came out and adjusted the valves again. I am mechanically inclined, but I didn't want to stand over his shoulder performing the work, and for $50.00 each time, I couldn't go wrong, so I thought. Fast forward to three weeks ago with 264 hours on the generator, I got an error code 1515. I was at camp and heard the generator trying to start during the weekly check. The generator did not start. I went out and cleared the code and then tried to start the generator while I was right there. It tried one time to start before starting on the second time. I thought all was good. I called the generator guy, but he never got back to me. Last weekend, I got error code 1515 again, during the weekly check. I called the generator guy again, but this time I got another guy. He said he was buying the business for the guy who had been coming out to do the adjustments. He said that he could come out in a couple of weeks and that he would have to charge me $150.00 plus mileage. After reading my owners manual and watching a video I decided to do the adjustment myself. Here are my questions;
1. On my 9 KW I have two nuts on top of the rocker arm (I assume the upper one is a jam/lock nut for the one below it). Am I supposed to leave those two locked together and use them to turn the pivot ball stud once I loosen the rocker jam nut that is tight against a plate below the rocker arm?
2. Why would they use two jam nuts on top of the rocker arm versus an elastic stop nut?
3. Is it odd that the first adjustment was made at 173 hours, the second 50 hours later, and the third 39 hours later, or is there something else going on?
4. I did pull the valve cover, plug, and did check the valve clearance with the piston at TDC. There was no clearance between the valve stem and the rocker arm. Pretty good design that the generator knows that, sends out a code, and prevents the generator from starting.
5. Is this valve adjustment a common thing on Generac generators? I have gas 7.3 KW Kohler genset on my boat with 453 hours, and a LP, 2003 Onan 12 KW with 350 hours and have never had to adjust the valve clearance.

I know this was long winded, but I wanted to give as much information as I could. Thank you in advance.
Tim
Chris
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A few things...

1. The rocker uses an adjustment nut and a jam nut to lock in the adjustment. If you adjust these at the incorrect spot in the timing cycle, you could destroy the engine...

2/3. You should never be needing this many valve adjustments. Either it was done incorrectly, or you're measuring the valve clearance at the wrong spot in the cycle.

4/5. Valve adjustments are necessary on any engine with solid lifters. Your other generators may have hydraulic lifters which don't require adjustments. That being said (and as covered above), your unit doesn't need adjustments that often unless something was done incorrectly or left loose... The engine is not throwing a code because it knows the valves are off. It's throwing a code because something is wrong with the engine and it's not starting. The 1100 code is for overcrank which could be related to the valves or fuel pressure.

1515 is an RPM loss alarm and means that the controller told the engine to crank but it didn't. Could be a battery issue, ignition coil problem, starter, etc.
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Tim F
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Hi Chris,
Thank you for your quick response. I do know how to find TDC. I have not made any adjustments to my generator, but I want to know how to do it correctly now that I know that I shouldn't have to make these adjustments as often as has been done on this generator. I am mechanically inclined, but I don't want to screw this up based on what could be the outcome. Ok, based on your response, I have a couple of questions.
1. In your response to #1, what are you considering the adjustment nut, is it the two nuts jammed together holding the rocker arm onto the pivot ball stud? I am using terminology from Figure 4-6 of my owner's manual.
My owner's manual says to loosen the rocker jam nut which sits against a metal plate below the rocker arm. The manual then says to turn the pivot ball stud using a 14 mm wrench to make your adjustments. The top of the pivot ball stud is where the two nuts are jammed together holding the rocker arm in place on the pivot ball stud. Based on those words, am I correct that it is the pivot ball stud that I will raise up and down by threading it CW or CCW (using a wrench or socket on one of the two nuts) to give me the clearance required between the valve stem and the rocker arm?
2. If this is correct, is it correct to assume that the two jam nuts holding the rocker arm onto the pivot ball stud should never be loosened or broken apart during the valve adjustment process?
Thanks again for your support.
Tim
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