Generac 36lp plus starting problem

[AnEv942]

I'm having a problem with our generator. When trying to start usually just grunts like a bad connection. Checked and cleaned all cables and wiring (that I can get to). I thought I had narrowed it down to starter solenoid, if I jump the terminals it'll turn over fine, which rules out starter or connection there I would think. Pulled it and tested fine, opened it up and inside terminals are fine. Reinstalled and discovered its the line that activates the solenoid. Some where between battery terminal and wire coming back to starter solenoid is either a bad connection (I assume) or component. Runs fine once started.

I found this older post from 88lover. Somewhere in this convoluted path is my problem, Unfortunately I cant back trace very far without dropping the generator just no access. Which I'm getting ready to do. Just though Id check if anyone has had similar issue and what i might look for.
Ill add when it does this grunting thing just dumps the battery?
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88lover on 10/16/09 03:36pm

On units with LP gas fuel system, the Fuel
Lockoff Solenoid (FS) will be turned on by closing
the Primer Switch.
CRANKING:
When the Start-Run-Stop Switch is held at "START",
the Wire 17 circuit from the A6060 circuit board is
connected to frame ground. Circuit board action then
initiates the following events:
1. Battery voltage is delivered to the Starter Contactor (SC) coil
via Wire 56.
a. The SC coil energizes and its contacts (SC)
close after a few seconds.
b. Closure of SC contacts deliver battery voltage to
the Starter Motor (SM1) via Wire 16. The engine
cranks.
2. Battery voltage is delivered to the Wire 14 circuit.
a. The Fuel Pump (FP) turns on.
b. Power is available to the Ignition Module (IM)
and ignition occurs.
c. Power is available to the Inverter Fan for operation.
3. A6060 circuit board action operates the automatic choke
through Wire 90.
The fuel lockoff solenoid is energized open by 12
volts DC power from the A6060 circuit board during
engine cranking. The solenoid can also be energized
open without cranking by actuating the fuel primer
switch on the generator panel
______________________

Edit 8/23/13


got it out..now what? for the next guy if this comes up in search
Found service manual at, http://www.generator-parts.com/manuals/generac-rv/0D1752.pdf.
These things work nothing like I thought- no surprise there. Power is basically at several places but hitting the start switch grounds the main board so it functions-as 88lover snipped from manual. Turns on gas, activates ignition and carb stepper motor then sends power to starter solenoid (contactor). The service manual outlines several test with simple multi meter that should lead to a solve.

However mine after going thru all the test procedures yielded nothing positive or at least a fix. Well simply because I'm not spending $200/300 on a board for 12 year old unit-at least right now. Its apparent the output from main board is the issue. Which I kinda figured out. Its a relay on potted board that's failing-it usually when starting will only supply a cascading downward voltage until starter solenoid cant stay open- instead of constant nominal 12v voltage while switch is depressed. This happens rather quickly-starting at 12 dropping to 0.5, once solenoid stops drawing (open) starts all over. So starter just engages then solenoid opens over and over as long as button is pushed. bout 1 in 12 will yield a start. Other functions still operate, by sending 12v manually to solenoid while holding the start button it will start. Once going runs and shuts down normally.



Pic of starter solenoid/contactor, sets behind small square box in front of gen. The blue wire is from the main board that when starter button pushed should deliver full 12 voltage, engaging solenoid and connecting the 2 large terminals together sending battery power to starter.
(IF you have full 12v at blue wire but not at starter terminal, contactor bad. IF you have 12v at blue wire, 12v at both large terminal then cable or starter issue)

So My fix for the moment is disconnect solenoid power wire from board, simply adding a momentary switch from another 12v source to activate starter solenoid. It'll be a 2 button-push normal start button then after a second or 2 hit the manual start-once it fires let go of both.
Because start switch works by ground and not sending power it cant be utilized. Otherwise Id add another relay triggered by start switch to send full voltage to solenoid. It could be done though using the ground to activate second relay but I don't want to use-and possibly interfere even slightly with remaining functions. It could also be done with a double throw switch so one side operated board-the other starter solenoid. But inside easier to add a small momentary.

Verified several times outside of camper this works. Rather amazed how much quieter it is outside of the tin box. Be nice to add some sound deader before I reinstall gen.

I did pull all the tins and shields to disconnect and clean all connections prior to finding the manual and testing.
Azsalotawire...
Another fyi I guess, though number of these Generacs is dwindling. Parts still available.
____________________

Edit 8/28/13:

Just updating. Performed intended mods-disconnect blue wire #53 from solenoid terminal that comes from bad relay on main A6060 board. Installed momentary switch on interior stove vent panel and another on gen panel. Ran these to the starter solenoid energizing terminal that #53 went to. Works.
Just as reference- what its supposed to do from the manual..


And What its not doing-Specifically #1a &1b.

And my bypass wiring




So we have generator again. This doesn't seem to be a common failure.
There are other failures that can keep it from starting.

Last comment-I assume most would not add the bypass switches- But, if your gen grunts when hitting start button check voltage at the starter solenoid terminal (blue wire). I did discover that if you briefly touch good 12v power to the blue wire terminal while holding the start button it would start-could save packing it up & heading home.

[AnEv942]

Odd, thread over 1 1/2 years old and hadn't slipped into archive.

If nothing else glad it prompted you to join and respond-welcome to the forum.

Yes among many other things, obviously bad batteries can be a source of non starting generator. Last thing you want to do, though simple task, is drop generator- everything possible needs to be ruled out first, and as with anything-start with the simplest. Due to the layout as noted, unfortunately you cant get very far when testing the gen without dropping.
Hopefully that wasnt read into this-that dropping gen should be done without verification of the more likely scenarios. Bad/loose connections, battery, starter contactor(solenoid) etc. Or simple corrosion on the exposed spade connectors to gas solenoid, thats a periodic/annual thing. If I don't hear the solenoid click-go clean the connectors. This was only offered as a workaround for a failed board. Ours has been working flawlessly since the 'bypass', but year & a half later the board is still bad.

Curious, While I have some healthy NI-CAD battery packs that are 25+ years old by religiously cycling, I had not heard before anyone applying that to lead/acid deep cycle battery. Glad it works for you- but not something I'm going to try though might research. Interesting

[harleyridertex]

As a truck camper owner with a Generac 36 lp plus 2....I will try to explain what the starting issue normally consist of..... Voltage and amperage are two different things....I had a issue with starting generator off of twin deep cycle batteries that I don't even remember their name....slow solenoid click and no starting.....Sounds like a dead set of batteries....I had 12.5 volts at battery connections and charger always said fully charged....Cleaned all of the cables.....Grounds included at Ginny frame....The circuit board is set to abandon operation at approxamatly 8.5 volts.....For fun jump the solenoid blue wire wit a small wire directly from hot terminal on solenoid....It will turn over the starter....When you use button the voltage drops and circuit board abandons the cycle.....Then volts come back up and starts cycle again just to be disappointed by batteries.....
When you try to start unit the voltage drops so fast a meter cant react fast enough....Just waves at you.....
The thing I did next was to pull the super heavy batteries out of that stupid box that is 6 foot off the ground....Set them on a bench and pop the caps off of all 4 sets of covers.....Look inside carefully and you will probably find a dry battery.....Deep cycle batteries need more maintence than starting batteries because the store more heat.....If the cells are dry don't add anything.....Go to your favorite Auto parts store and have them tested....be sure you take your credit card because they wont let you take the new ones out without paying....Mine were 116.00 each....Leave your old batteries for the recycle core......I wound up with autozone duralast deep cycle....27 dc....High cold crank and the storage ability is very high.....180 min at 25 amp....That quiet a good storage capibiliy....When I hit the button now it opens gas valve and sounds like its on steroids
Now for my thinking....For a while I had trouble starting generator....I could hook up electrical from truck and start engine....let it run a few minutes and gen would start....truck is hitting batteries with average 14 volt and actually forcing a charge to jump off generator.....Most newer trucks have a relay that seperates truck charge wires from camper when the engine is off to keep from not start on truck because camper batteries went down
Another train of thought is I have a solar panel on roof to keep batteries topped off at all times of no use....Daylight charging everyday makes acid in battery warm up and evaporate......
Always test the easiest system first and work your way back......These circuit boards are pretty tough.....And learn to turn batteries off when hooked to shore power.....Let the batteries rest until needed.....I have a trick to get the maximum charge into batteries....turn on a 12 volt light in camper....unhook from shore power and let both batteries completely discharge....Then hook up charger and slow charge them until full....deep cycles like that
I hope this helps someone that is thinking of pulling unit out to test it....Im amazed they built the service access to the side and stuffed it so full of wires
Happy Camping