Generac generator starting issues

[zzjea]

I have been dealing with this for a long time and have tried about everything possible but still no real answer. It will now start most of the time when all conditions are perfect: Batteries have charged for several hours and all fingers crossed. I have replaced the starter, the starter solenoid, cleaned all known contact points both positive and ground, 4 house batteries show full on control panel. However, after running the genset for any period of time, it will not restart again until hours or the next day if at all. It will try to turn the starter over but acts like it does not have enough amps, even when engaging the battery boost solenoid.

If I was not connected to shore power for the batteries to charge, I don't think it would start. I even tried jumping directly to the genset positive connection at the genset from a car's battery with same results. However, sometimes it will start like it's supposed to from house batteries.

The story is much longer than I have described (about 3 years now) but I wonder if anyone is familiar with something like this?

2001 National Marlin 390 (39' +)
Cummins 300hp diesel
Generac 75D diesel (7.5kw)
Xantrex 458 20
4 6v Trojan house batteries (2 years old)
2 12v chassis batteries

John

[BFlinn181]

Have you ever taken voltage readings as you attempt to start the generator? It sounds like a dirty connection or ground problem. I'd start with readings during start attempts. You could then add jumper wires at the ground and/or positive supply to the generator starter and see if it changes things.

[Charlie 5320]

Originally Posted by zzjea

I have been dealing with this for a long time and have tried about everything possible but still no real answer. It will now start most of the time when all conditions are perfect: Batteries have charged for several hours and all fingers crossed. I have replaced the starter, the starter solenoid, cleaned all known contact points both positive and ground, 4 house batteries show full on control panel. However, after running the genset for any period of time, it will not restart again until hours or the next day if at all. It will try to turn the starter over but acts like it does not have enough amps, even when engaging the battery boost solenoid.

If I was not connected to shore power for the batteries to charge, I don't think it would start. I even tried jumping directly to the genset positive connection at the genset from a car's battery with same results. However, sometimes it will start like it's supposed to from house batteries.

The story is much longer than I have described (about 3 years now) but I wonder if anyone is familiar with something like this?

2001 National Marlin 390 (39' +)
Cummins 300hp diesel
Generac 75D diesel (7.5kw)
Xantrex 458 20
4 6v Trojan house batteries (2 years old)
2 12v chassis batteries

John

Does your generator have a ground wire from the case to the vehicle frame? Or does it rely solely on the bolts holding the case in? Sounds like a dirty ground. If it has a cable to frame, try taking it off both ends and clean them real good. If it doesn't try adding a cable from the case to the vehicle frame.

[zzjea]

I did add a cable from the starter mount bolt to the chassis frame. I think it has helped but I still have the same issue at times.

[gatorcq]

Bad starter, is what it sounds like. Since connections are clean. Ground strap.

By the way, you stated, runs, shut down, then problem starting. The key here is the HEAT.

Have you removed the front cover and try to turn the generator over by hand, when cold (baseline) and when it does not start. If it turns about the same, then I would still go with starter. This is done on the left side, you will see generator belt.

Among our members, (Alfa's), we have a few resident experts on the Generac.
Yes, we have had a few starters replaced, and guess what, starter goes bad or received a bad starter.
We are lucky, starters only cost around $80 to $100, for a 75D.

[chboone]

Was the starter you installed a rebuilt/remanufactured one? If it was and from an unknown rebuilder it my be a poor rebuild. Take the readings BFlinn suggested. If that doesn't work find a good rebuilder have them check the starter and rebuild if necessary. Not always easy to find a good rebuilder because the cheap junk the production shops put out have put them out of business.

[zzjea]

Have not been able to test during startup yet. The starter is a brand new Generac (1 month) and I have added a direct ground cable from the starter mount to the chassis frame. The flywheel seems to turn okay. It will start sometimes but not other times which is a mystery.

I need to check voltage during startup.

[jimnkee]

If it's sluggish like not enough power from the battery it has to be a battery connection problem or battery problem. I would check all the connections between the battery and starter.

[BFlinn181]

There are many YouTube videos on testing starters. If you pull it off, many auto parts stores will bench test it for you if you don't want to do it yourself.

[KEH]

John, I have almost same setup as you in my 02 Tradewinds and have had same issues. Replaced starter and cleaned ground at frame, but still ever now and then the starter drags and gen won't start.

[zzjea]

Originally Posted by KEH

John, I have almost same setup as you in my 02 Tradewinds and have had same issues. Replaced starter and cleaned ground at frame, but still ever now and then the starter drags and gen won't start.

I would be interested in what you have tried as I have tried everything. Have you replaced the starter solenoid? I did several years ago but it is very hard to get to under the genset. I had it out recently and should have replaced it again just to be sure. I have even connected my car battery with jumpers directly to the genset and still had similar results.

[bigdog]

I also have had this problem since day one 7 years ago. The generator started ok for several months and then went into the rrrrrr,rump,rump mode. Had three starters replaced at the same time, first two were Generac original parts and then they said to go with the aftermarket one which worked ok for two months. I have had 6 starters in it in 5 years as I gave up on it after the last time. Last time it was replaced the tech said it was drawing 300 amps which I thought was a bit on the high side. My aftermarket warranty is running out pretty soon and since it's covered, I'm gonna get it done again. I have cleaned the ground wire from the case to the frame and even ran a new heavier wire to a different spot that I very carefully scraped and used a clamp instead of trying to drill a hole. I borrowed my neighbors F350 PSD and tried to jump it with that,but no go and then used my charger with the 90 amp starting jolt and no go.
I'm thinking that maybe the heater fuel pump switch may have something to do with it too. They say to hit that switch for 15-30 seconds before hitting the start switch and keep hitting the heater switch, but all that seem to do is draw the battery down.
Some times tho, it will start.

[zzjea]

Originally Posted by bigdog

I also have had this problem since day one 7 years ago. The generator started ok for several months and then went into the rrrrrr,rump,rump mode. Had three starters replaced at the same time, first two were Generac original parts and then they said to go with the aftermarket one which worked ok for two months. I have had 6 starters in it in 5 years as I gave up on it after the last time. Last time it was replaced the tech said it was drawing 300 amps which I thought was a bit on the high side. My aftermarket warranty is running out pretty soon and since it's covered, I'm gonna get it done again. I have cleaned the ground wire from the case to the frame and even ran a new heavier wire to a different spot that I very carefully scraped and used a clamp instead of trying to drill a hole. I borrowed my neighbors F350 PSD and tried to jump it with that,but no go and then used my charger with the 90 amp starting jolt and no go.
I'm thinking that maybe the heater fuel pump switch may have something to do with it too. They say to hit that switch for 15-30 seconds before hitting the start switch and keep hitting the heater switch, but all that seem to do is draw the battery down.
Some times tho, it will start.

What year and model is your MH. When you tried jumping, did you ever go straight to the starter with the jumper and see if it would turn the engine? I tried that and was shocked when it did its usual grind. I have added a permanent ground (battery cable) from the bottom stud of the starter to a welded bolt on the chassis frame bypassing any grounding issues there could be from the starter to chassis ground. I have been sick (bad cold) for over a week and have not been able to test voltage drops at various places in the circuit from the batteries to the starter. It's about a 40 foot run from the batteries to the control panel, to the jacks and then all the way to the front of MH where the genset is. I also need the DW to be willing to assist pushing the starter.

My latest idea is that the starter solenoid may have burned contacts although it has seen very little use. I had it out recently and should have replaced it. It may be a combination of several issues that result in the solution.

Testing the power circuit is the best step forward and I don't know if you have done that yet.

You're the first person to have my exact same problem. Maybe we can figure this out together.

John

[aether_one]

Back in the day you would have this problem on some V8 engines when hot due to the Bendix gear and flywheel binding. I believe it was fixed with shims on the starter.