# Troubleshooting old Generac NP-52G



## deanrantala (Nov 9, 2020)

Couple questions on an old Generac NP-52G.

First issue: not putting out power. I checked and even the (24vac?) low voltage [battery charge] winding was dead. At first, I thought maybe the "field boost" circuit was not working (on this model, it runs through the choke module and give a temporary charge while cranking).. but no.

What I did: using my PowerProbe (love them things).. I disconnected the the regulators connection to the field coil and directly applied 12vdc to the fields [+] tab (back side of plastic housing closest to bearing). Presto! While applying the 12VDC to the field... I can run a circular saw from the genset. 

Question 1: safe to assume the VR is toast, right?

Question 2: what is the typical regulated voltage range that _should_ be applied to the field winding? I ask because... rather than the $130, I have considered sticking a small arduino in there with a connected MOSFET and writing a small program to regulate the voltage. From what I understand, the factory regulators were very prone to failure to begin with. I did not measure the output voltage when applying the 12VDC (would need extra hands), but it seems to produce more/less full 120V when the 12VDC is applied. 

The next issue is hard-starting after it sits for a few hours. I took the carb apart and cleaned it out completely. Immersed it in paint thinner, ran thin wire through all the ports, etc. It starts, but only after cranking for upwards of 8-10 seconds. Even then.. sometimes it barely wants to "grab".. but finally it does. Once it does start, it runs absolutely perfect. No hunting/surging. And the governor kicks in and speed adjusts just fine when I place a load on it (after manually providing power to the field coil as mentioned above).

I hear these things had some issues with the choke.. but in this case it seems to be working "according to the manual". While cranking, the choke valve cycles every couple seconds, and once running it opens.

Manually holding the choke closed while cranking seems to help a little but not always - and not a lot.

Question 3: are there any "secrets" or "tricks" anyone is aware of to this carbeurator? Were all these generators like this originally? I got half a mind to adapt a newer carb to this thing and do away with the one one it since it is discontinued and NOBODY makes any parts for the carb any longer. It is an old Japanese TK carb.

Maybe I just need to really run it for a while under load? This generator seems to have sat for many years before I got it. Fuel lines looked to have cobwebs in them!

Many thanks!


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## deanrantala (Nov 9, 2020)

One other question: what exactly is the "DPE" or "DFE" winding for?

I notice this generator has:

2 Power windings (for AC output)
1 Field winding (on the stator)
1 "DFE" or "DPE" (hard to discern/read from the PDF)

Strangely enough, the voltage regulator is connected to BOTH one of the power windings AND this "DFE" winding. This "DFE" winding is connected ONLY to the VR through a 2.5 amp automatic circuit breaker. Perhaps the VR uses the [rectified] power from this "DFE" winding to provide itself and the field with power and uses the connection to one of the power windings only for voltage monitoring? The manual says this has under and over voltage protection. Although, I would have assumed you could have monitored the status from this "DFE" winding the same since the change in voltage will be the same proportionately across all coils as a matter of the induction between them.


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## ToolLover (Jan 13, 2020)

I am thinking you might look to the below listed website for a more in depth answer to your question.





Ziller Forum







www.zillerstore.com




Then pick up on the forum.
These guys are Generac guru's.
I have found the members to have some in depth info on Generac's that was interesting to know.


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## deanrantala (Nov 9, 2020)

So, I my account on Ziller is pending approval.

I can tell you one thing: I have seen the light with propane. Call me Hank Hill if you want. (mumbles "I sell propane and propane accessories")

I solved the carb issue.

Since the carb's on these are unobtanium and no longer exist (some similar ones exist for over $300 and require mods).. I decided to convert this thing to propane.

How I did the conversion:

First, I got on Amazon and found a random propane-ready carb for an engine of 12-18 horsepower (was NOT for the Generac NP-52g). My plan was NOT to try adapting this new carb to the Generac, but instead a cheap way to obtain a correctly-sized [demand-based] regulator AND bonus: even now got the proper-sized jet needed and even a rough "blueprint" example for converting the original carb. Total price for the brand new carb from Amazon: $28. This is far cheaper than the $120+ "kits" you can buy on various sites and provides you with (literally) all the same components. 

Next, I carefully removed the regulator and propane jet from the NEW carb. Now on the OLD carb... I removed the float bowl, choke, fuel inlet fitting, all the jets, and even some un-needed cast appendages where the float bowl rested against. I then drilled out the hole for the original jet and press-fitted the NEW propane jet (that I removed from the new carb) into the drilled hole with my bench vise. I was careful to press the tip through so that it protrudes the same exact length into the venturi as it did on the NEW/original carb. Sealed up all the extra holes from (including for the old choke and idle circuit) with RTV (Ultra Grey). I was also able to remove all the electric choke crap that sits under the carb as well as the fuel pump. 

Needless to say... after this butchery, the carb will never see gasoline again. This is now a propane-only carb.

Hooked it all up with a $15 BBQ grill regulator (also sourced from Amazon) and **** thing fired up first lick. Smooth. Steady. ****... I am DONE with gasoline generators. I even let it sit a couple days and came out to try starting it again.. same result: effortless starting, levels out fast, and just works. No more choking the carb, no more fuel pump.. entire setup is now simpler and will be less prone to failures.

So long as I keep the oil and filter changed, I should easily get another 30 years of service out of this engine given how much easier propane is on engine internals.

Now to sort through this voltage regulator... I will have a super quiet standby generator.


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