Generator turns over but won't start

inlyzbldcj · 07-08-2021, 08:31 PM

Ok so we bought our RV in Jan....2017 genny only has 461 hrs on it...went to start it yesterday for it's usual weekly hour run with the load of two TVs on it while running, but it won't turn over...it just tries but won't start....any suggestions? Gas tank is at 3/4 so I know it's not the 1/4 tank of gas thing....never had a problem with it till yesterday....also tried priming it first and still no turn over.

Trkyte@msn.com · 07-08-2021, 09:17 PM

By saying it won’t turn over. Do mean it cranks but not firing?

inlyzbldcj · 07-08-2021, 09:23 PM

yes sir

lwmcguire · 07-09-2021, 10:07 AM

Changed the spark plug lately?

inlyzbldcj · 07-09-2021, 02:30 PM

I am actually having it serviced right now for the overhead bed that we had an issue with and told them to do a full oil change and service on the generator while it's there....supposed to get it back Tuesday so fingers crossed.

pneumatics · 07-09-2021, 07:41 PM

If you tried to start it at the genset (a good way to start troubleshooting) did you get any lights flashing when it failed to start after a time cranking?
These are error codes and give you direction on which way to look....

chunker21 · 07-10-2021, 11:51 AM

Quote:

Originally Posted by inlyzbldcj

Ok so we bought our RV in Jan....2017 genny only has 461 hrs on it...went to start it yesterday for it's usual weekly hour run with the load of two TVs on it while running, but it won't turn over...it just tries but won't start....any suggestions? Gas tank is at 3/4 so I know it's not the 1/4 tank of gas thing....never had a problem with it till yesterday....also tried priming it first and still no turn over.

Couple of comments and a question. Assuming it's a gas generator, did you sufficiently prime the generator? A weekly run is not recommended it's monthly and it's recommended a moderate load, some use 50% power, while being exercised. A television draws very little power so most people use the air conditioner to get sufficient load.

Jimbo56 · 07-10-2021, 01:09 PM

Mine is the 4000. I have to prime it for a count to 45 before it’ll start. How long are you priming?

Jimbo56 · 07-10-2021, 01:12 PM

[QUOTE=Jimbo56;303004]Mine is the 4000. I have to prime it for a count to 45 before it’ll start. How long are you priming? And is your use/store switch in the use position?

**16ACE27** · 07-10-2021, 02:06 PM

[QUOTE=Jimbo56;303005]

Quote:

Originally Posted by Jimbo56

Mine is the 4000. I have to prime it for a count to 45 before it’ll start. How long are you priming? And is your use/store switch in the use position?

USE/STORE switch has no bearing on starting the generator.

Chateau_Nomad · 07-10-2021, 05:18 PM

Gasoline engine "no start" conditions can be narrowed to 2 common scenarios... lack of fuel and/or lack of ignition spark.

The simplest of problems for lack of fuel is no fuel supply (empty tank) or blocked fuel line (clogged fuel filter). Also, most motorhomes cut fuel flow to the generator if the main fuel tank is below a certain point.

A spark problem can be harder to diagnose, but the obvious is a loose plug wire. You can CAREFULLY check for spark by safely creating a gap between the plug wire contact end and a ground - and check for spark while cranking. ONLY DO THIS IF YOU KNOW WHAT YOU'RE DOING!!

So, satisfy all those conditions. If you're getting fuel and a spark, the engine should at least fire. If not, it's a more involved issue for a Cummins tech to solve.

Pete'sMH · 07-10-2021, 05:26 PM

[QUOTE=16ACE27;303011]

Quote:

Originally Posted by Jimbo56

USE/STORE switch has no bearing on starting the generator.

Mine does. Generator starts on the house battery so is incapacitated with house battery disconnected,

Debbie124 · 07-13-2021, 10:39 PM

Mine is off the inuse switch also. I had same problem and house batteries needed changing

dkoldman · 07-13-2021, 11:01 PM

I recall a brand new 2019 27B Hurricane that we went to see that would not start. Engine would not start, nor would generator as batteries were dead. Sales had called a service guy to brink a battery pack; but it was hot and we were tire of waiting. Salesman tries the emergency button and somehow got just enough power for the generator to start

He hated he did though, because the service guys never showed up with jump battery pack; we left to go launch and came back and 3 hours later it was still 90+ degrees on that Firefly pad. It had two AC units

I confirm that on my coach if House switch is OFF, my genset will not start with either of remote switches, nor direct at the generator. The AGS is also powered by house batteries; so if batteries are not supplying power; it cannot work.

**16ACE27** · 07-14-2021, 12:36 AM

I can't speak to SOB coaches but historically Thor MHs have the generator start power go from the house batteries through a separate 100 amp DC breaker and NOT through the battery disconnect to the house DC buss (USE/STORE latching relay).

However, if you have no power to the DC buss because the battery disconnect relay is open you may not be able to start the generator remotely or through any powered down computerized interface. You should still be able to start it at the generator.

Beau388 · 07-14-2021, 12:55 AM

Quote:

Originally Posted by 16ACE27

I can't speak to SOB coaches but historically Thor MHs have the generator start power go from the house batteries through a separate 100 amp DC breaker and NOT through the battery disconnect to the house DC buss (USE/STORE latching relay).

However, if you have no power to the DC buss because the battery disconnect relay is open you may not be able to start the generator remotely or through any powered down computerized interface. You should still be able to start it at the generator.

That is the way all Plant 750 coaches are wired except for the 2018 and later modifications shown. This is for a 50 amp coach although the wiring for a 30 amp is the same but the circuit breaker and cable sizes are different.

Miramar Owner · 07-14-2021, 01:03 AM

From experience... If in store mode on my 2016 Miramar, the AGS will start the generator but not charge the batterues... Just a side note from a time I had it in storage and forgot to turn off the AGS.

If I understand what he is saying, it turns over but doesn't fire... Doesn't sound like a battery issue.

dkoldman · 07-14-2021, 01:25 AM

Quote:

Originally Posted by 16ACE27

I can't speak to SOB coaches but historically Thor MHs have the generator start power go from the house batteries through a separate 100 amp DC breaker and NOT through the battery disconnect to the house DC buss (USE/STORE latching relay).

However, if you have no power to the DC buss because the battery disconnect relay is open you may not be able to start the generator remotely or through any powered down computerized interface. You should still be able to start it at the generator.

The drawing speaks for itself. Speaking in reference to my experience with the 2019 27B Hurricane, the drawing may explain why or how the salesman got the genset to start when batteries were low (or perceived dead) and to the fact based on this drawing that the House Switch would have no impact on the genset starting. There is an ISO relay that I assume is controlled by the emergency switch? If so; the batteries alone did not have enough power to turn over the generator and the chassis battery alone did not have enough power to turn over the engine. As I recall, the salesman had me hold that emergency switch while he did something with the Firefly controller on the wall. The momentary switch combining both batteries was just enough. The Generator started

But I concur my scenario is / was independent of the House Disconnect switch. But I have no proof of that because the House switch was on the entire time. I would need to see the wiring source that provide the 12vdc power to the Firefly to confirm. If that source is downstream the House Disconnect switch, User may have to start the genset direct at the generator.

But for my NON Thor model, the House Disconnect must be on. The AGS Panel is dead, and trying to turn on direct at generator will get you NOTHING. I actually like knowing in the event I inadvertently left my genset in AUTO mode, but intentionally wanted to shut my coach down by turning off the House Disconnect switch. I know my genset will not START or come on PERIOD.

racochran · 07-14-2021, 08:35 PM

I had 2 instances of generator won't start. The first may not apply but may help some. Generator would crank and start and soon as start button release it would stop. Problem mice got in and chewed threw brush wiring so no voltage output. I have not looked further but appears if no voltage output sensed generator will stop. Second problem which may apply I just recently in last 2 weeks fixed. 1 of the 2 house batteries was died or nearly so. Not sure how only one but I found this when removed batteries to put on bench to charge. The 1 battery pulled down voltage enough from 2 battery not enough total voltage to crank generator. It would click is all then nothing.

I was going to replaced both batteries to be safe and decided to play a little. The 1 bad battery kept showing a bad cell when on normal charge. I have a boost setting of 10 amp so hit it with that and after a bit it dropped back to 2 - 6 amp normal charge. It held that and stopped showing dead cell. I put a load tester on it of 300 amps then paused for 15 seconds and hit it again. Did this 3 times and all 3 times it passed.

Reinstalled batteries and generator started right up as normal. As to the 1 battery that I played with it is suspect to say the least. Will monitor it and if happens again 2 new batteries in the future. By the way date codes on both batteries show same month and year 2018 of manufacture and I keep a Battery Minder on them trickle charge and desulfication when in storage. The Battery Minder 1510 was on the batteries before and now after the no start generator. So it did not help in this situation maybe because of 2 batteries in parallel I am not sure.

Probably should use a hydrometer to test the individual cells. I really don't want to get caught out with a bad battery.I am not sure why I don't have one I seem to have everything else!

Oh and my rig is a 2019 Thor Chateau 28E.

chunker21 · 07-14-2021, 09:28 PM

Quote:

Originally Posted by racochran

Probably should use a hydrometer to test the individual cells. I really don't want to get caught out with a bad battery.I am not sure why I don't have one I seem to have everything else!

Oh and my rig is a 2019 Thor Chateau 28E.

Assuming we're talking house batteries, if it dies, start to fail just remove it from the bank. Not physically, electrically. A bad or weak battery will draw down a good one as you have found. If you are on hookups you won't have an issue, if boon docking then that's another issue. My former DP had 3 house batteries, not very expensive ones at that, FLA GP29s, and one on a long trip crapped out. I disconnected it from the bank and had no further issues.

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