generator possibly fuel in the oil?

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generator possibly fuel in the oil?

November 30, 2022, 12:11:39 pm

Much of the last few months has been getting the new to me coach (95 U295 Unihome) up to speed. One of the remaining primary tasks is the generator. When I first found the coach and had an interest in buying it, I arranged for an inspection by a mobile diesel mechanic to check out the engine, trans and generator. Word from the mechanic's inspection was good. Engine and generator started easily and ran fine, no issues or probs reported. That was Aug 2021.

I personally have not started the generator. I do have video of it running from that inspection by the mobile mechanic. I didn't start it because a) I didn't need it and b) I wanted to do an oil/ filters change before using it on any regular basis. This was planned for Spring as I'll need to locate a place to do it; both my storage facility and my usual campsite prohibit that repair on-site. But, as a longer trip south is planned in the next couple of weeks, I thought it might be needed on that trip and was going to give it a test. (Till now my focus had been on the inside, engine and appliances.) In checking the oil and fluids before starting the generator up, I noticed the oil seemed over-filled. Like very overfilled. First time I've seen that on any generator. I expected to find the opposite.
Upon a closer look at the dipstick and oil, it smells a bit, fairly strongly even, of diesel fuel. So I'm suspecting that the reason for appearing overfilled is due to fuel in oil. So the question is how and when. I have to think if it had been like that for the inspection I had by the mobile mechanic it would have smoked a good bit on startup and that would've been noticed and noted. But if it wasn't that way then, then how'd it happen in the intervening period that I've had it but not used it? The only thing I've done that could possibly come into play is fill the fuel tank, which was just above a quarter of a tank at time of purchase (and so also time of the inspection by the mechanic.

Obviously, I'm not going to start it until I can do an oil and filters change on it, so it's not going to be until spring at this point and will have to count on making the upcoming trip without it. Any ideas on the matter are appreciated. The generator is the Powertech 10k.

Bill

Re: generator possibly fuel in the oil?

Reply #1 – November 30, 2022, 12:25:26 pm

There is no way for fuel to get in the oil without the electric fuel pump running. Even then getting into the crankcase without the engine running and a very bad injector is strange. Wait and see if it has happened to anyone else. I personally would in your case change the oil and refill correctly and see what happens. The engine can run without smoking with diluted oil and diesel, which might have happened during the inspection but the oil level would have showed overfull.

Re: generator possibly fuel in the oil?

Reply #2 – November 30, 2022, 12:43:25 pm

I would get the oil changed before your trip. You may not need it but what happens if you do? I would not start generator until after your oil change. It is possible that someone added oil just after running the engine with oil not having drained back to the pan and thought it was low. Once you change the oil you can then see if the level goes up.

Re: generator possibly fuel in the oil?

Reply #3 – November 30, 2022, 01:08:03 pm

Once you change the oil you can look at the old oil and see if any diesel is in the oil.

Re: generator possibly fuel in the oil?

Reply #4 – November 30, 2022, 03:32:40 pm

Quote from: oldguy – November 30, 2022, 01:08:03 pm

Once you change the oil you can look at the old oil and see if any diesel is in the oil.

And here, let your nose be your guide, along with lighter viscosity if there is diesel dilution.

Re: generator possibly fuel in the oil?

Reply #5 – November 30, 2022, 06:19:20 pm

Similar story, I had a motor ruined because of fuel in the oil. The oil level was high and I didn't think anything of it at the time. Ran it a few times and soon couldn't get it started. The rings had wore because of the diluted oil. There was a crankcase pump that moved fuel to the carb, the heating and cooling cycles of day/night was enough to pump the fuel past the carb needle or however and into the crankcase. After I replaced the engine I have always turned the fuel off.

I'd say you were wise not to start it, whatever the situation is.

Re: generator possibly fuel in the oil?

Reply #6 – November 30, 2022, 06:29:36 pm

Quote from: wolfe10 – November 30, 2022, 03:32:40 pm

And here, let your nose be your guide, along with lighter viscosity if there is diesel dilution.

Exactly. It def smells of diesel. And the color and viscosity are off, you can feel it. 95% certain of it being fuel in the oil.

I have no intention of starting it until drained and changed. So for the time being, the generator is just an expensive, hidden, hood ornament. Honestly, I'd much rather it was a propane generator.

Bill

Re: generator possibly fuel in the oil?

Reply #7 – November 30, 2022, 06:41:18 pm

Diesel into the crankcase almost always comes from the mechanical lift pump diaphragm failure. Since your generator has an electric lift pump, it cannot leak into the crankcase. A Bosch injection pump seal failure is a slight possibility but I have never seen one.

Typical generator or main engine oil color is black, dark black and it does not take very long to get that way after a recent oil change.

If you are solar, you won't need the generator much but if you run the AC a lot, the diesel is going to be a lot less expensive even though the propane is cheaper. Diesel generators don't give much trouble if you maintain the filters and belt and watch the supply line for cracks.

Pierce

Pierce

Re: generator possibly fuel in the oil?

Reply #8 – November 30, 2022, 07:06:28 pm

I had a Yamaha outboard motor that was "making oil" and was told it would cost more to fix it than the motor was worth.
It froze up shortly after so I replaced it. Then someone stole the one that was froze up, saving me the headache of disposing of it myself.

Re: generator possibly fuel in the oil?

Reply #9 – November 30, 2022, 07:29:18 pm

Quote from: Pierce & Gaylie Stewart – November 30, 2022, 06:41:18 pm

Diesel into the crankcase almost always comes from the mechanical lift pump diaphragm failure. Since your generator has an electric lift pump, it cannot leak into the crankcase. A Bosch injection pump seal failure is a slight possibility but I have never seen one.

Typical generator or main engine oil color is black, dark black and it does not take very long to get that way after a recent oil change.

If you are solar, you won't need the generator much but if you run the AC a lot, the diesel is going to be a lot less expensive even though the propane is cheaper. Diesel generators don't give much trouble if you maintain the filters and belt and watch the supply line for cracks.

Pierce

Pierce, that's the other odd thing and what I noticed first before the smell test. The oil is black, but with too much transparency at the same time. First sniff and I could smell the fuel contamination. Added with the observed dramatic overfill on dipstick it seems conclusive. Prob not gonna be able to accurately diagnose the why, I guess, until changing it out, running it with new and timing it till how long until it recurs.

My goal is to add solar capacity to reduce the need for even having the generator. But that was also on deck as a next season project as it will be easier with a concurrent inverter and lithium battery upgrade. Still, I do like the idea of the generator as a last line back-up system.

My comment on wishing it were propane is purely based on a non-randomized and low power study of fellow RVers I know. Those with propane generators seem to have a more trouble-free time of it.

Bill

Re: generator possibly fuel in the oil?

Reply #10 – November 30, 2022, 07:56:43 pm

Once this is resolved, most recommend the generator be run at least once per month, under load, until fully warmed. Better for the geerator head and for the engine.

Re: generator possibly fuel in the oil?

Reply #11 – December 01, 2022, 01:21:40 am

Quote from: markb – November 30, 2022, 06:19:20 pm

Similar story, I had a motor ruined because of fuel in the oil. The oil level was high and I didn't think anything of it at the time. Ran it a few times and soon couldn't get it started. The rings had wore because of the diluted oil. There was a crankcase pump that moved fuel to the carb, the heating and cooling cycles of day/night was enough to pump the fuel past the carb needle or however and into the crankcase. After I replaced the engine I have always turned the fuel off.

I'd say you were wise not to start it, whatever the situation is.

You are talking about a gas engine with a carburetor. What you describe is called percolating, the gas in the carb expands in heat, runs down the venturi then cools at night the float drops and more fuel is sucked in. Very common on lawnmowers, outboard engines and other engines with a carburetor. Diesel engines don't have that issue.

Re: generator possibly fuel in the oil?

Reply #12 – December 01, 2022, 08:47:05 am

Quote from: craneman – December 01, 2022, 01:21:40 am

You are talking about a gas engine with a carburetor. What you describe is called percolating, the gas in the carb expands in heat, runs down the venturi then cools at night the float drops and more fuel is sucked in. Very common on lawnmowers, outboard engines and other engines with a carburetor. Diesel engines don't have that issue.

Exactly. Why I added whatever the situation is...

Re: generator possibly fuel in the oil?

Reply #13 – December 01, 2022, 08:49:07 am

Quote from: Stonyfork – November 30, 2022, 12:11:39 pm

tarting the generator up, I noticed the oil seemed over-filled. Like very overfilled. First time I've seen that on any generator. I expected to find the opposite.
Upon a closer look at the dipstick and oil, it smells a bit, fairly strongly even, of diesel fuel. So I'm suspecting that the reason for appearing overfilled is due to fuel in oil. S
Obviously, I'm not going to start it until I can do an oil and filters change on it, so it's not going to be until spring at this point and will have to count on making the upcoming trip without it. Any ideas on the matter are appreciated. The generator is the Powertech 10k.

Bill

Let's stick with what we know and not worry about what might be, and that being said, if the previous owner ran the generator monthly without a load, that would cause unburnt fuel to collect in the sump. That's why we always apply a load to the generator. Or any diesel engine.

Re: generator possibly fuel in the oil?

Reply #14 – December 01, 2022, 11:29:39 am

Can you get hold of the mobile mechanic who checked your coach. He should have checked the oil in
the generator before he started the engine. Find out where the oil was on the dipstick. You said you
filled up the tank so could the tank gravity feed? Pull the line off after the fuel pump and see if fuel
runs out. If it does, the question is can the fuel get into the engine as when the fuel pump is on the
excess fuel gets returned to the tank.

Re: generator possibly fuel in the oil?

Reply #15 – December 01, 2022, 11:51:42 am

Many people overfill their cars, RV, etc when they change oil. The PO also might have used a low viscosity synthetic oil like SAE 0-30 or 40. I changed to a synthetic oil for the generator quite a while back.

Unless it was to power the house, the generator is lucky to get started once a month and I don't usually put a load on it. The oil level never changes. We have a diesel house generator so the RV unit is lucky to get started every two months.

I posted a maintenance guide for the PowerTech a year or so ago covering a breather modification so the compartment stays clean, how to belt tension and part number, hoses, engine mounts, installing temp and fuel pressure gauge, etc.

Pierce

Re: generator possibly fuel in the oil?

Reply #16 – December 01, 2022, 10:21:52 pm

Appreciate the replies and some avenues to consider. I'm doubtful the 2nd owner gave the generator much of a regular run under load. In fact, that's a pretty solid bet. A big part of the reason for he and his wife selling was lack of use due to some age related infirmities. He held onto it as much for the memories and hopes it represented rather than the actual use of it and I can see myself having done the same. I should add I'm actually very pleased with the coach overall, so I don't view this particular issue as an unwieldy negative.

As with any used coach (or vehicle or house, even) this was an " inherited" problem. And I'll admit my parameters were very narrow when I was searching for the FT for me. I wanted full walnut paneling, 36' or under, and no slides with a good engine and drivetrain. Everything else I was willing to tolerate a bit more "que sera sera." I'm the 3rd owner, so though most of us know it's good to exercise the generator for premium performance, it's mostly out of one's hands what any of the previous owners chose to do...which is why I had a mobile mechanic do an inspection pre-purchase. I also knew even with a good inspection, there would be a history mystery that was part of the deal. This'll have to go in that category.

I've pieced together what I can from the records I have, though they definitely aren't complete. I'm not optimistic asking the mobile mechanic what he remembers would give me much more info, especially as it was over a year ago that he did the inspection. Had there been more time and a more amenable place to do it, I would have already gotten the oil changed and gone from there. The limitations of time and place did nudge me to outsource a main engine PM service and that shop was also amenable enough to take on the all 8 Koni shock upgrade on kinda short notice. I had asked if they'd have time to also do the oil/filters on the generator but that was not something they could add in to the schedule and I think they ultimately didn't want to mess with the generator as they are primarily a long haul truck service operation. (though they do accept a few regular motorhome clients, mostly diesel.) I'll ultimately get the generator back up to speed, albeit not as quickly as ideal and likely not before the drive south.

On my way to retrieve the coach from the shop tomorrow actually.

I need to name it; writing "the coach" is awkwardly repetitive. lol.

Bill

Re: generator possibly fuel in the oil?

Reply #17 – December 02, 2022, 08:48:18 am

Quote from: Stonyfork – November 30, 2022, 07:29:18 pm

My comment on wishing it were propane is purely based on a non-randomized and low power study of fellow RVers I know. Those with propane generators seem to have a more trouble-free time of it.

Bill

Those of us with propane fuel'd generators also spend more money for the electricity produced. We rationalize this y factoring in the purchase price of a diesel powered generator. Speaking for a friend.

In lieu of a second post, most RV generators that I've had experience with have a quick drain valve and drain hose for the crankcase oil. If push comes to shove, strategic parking at WalMart, an oil drain pan, oil and a funnel maeks for a quick oil change.

Re: generator possibly fuel in the oil?

Reply #18 – December 02, 2022, 09:44:03 am

Quote from: Old Toolmaker – December 02, 2022, 08:48:18 am

In lieu of a second post, most RV generators that I've had experience with have a quick drain valve and drain hose for the crankcase oil. If push comes to shove, strategic parking at WalMart, an oil drain pan, oil and a funnel makes for a quick oil change.

You will also be able to leave the old oil at the Walmart oil disposal station. Just get oil filter from a autoparts store vs a Walmart.

You said you are going South. If you don't change the oil hope you will not need the Roof AC's while traveling. It is going to be in the low 80's next week.

Re: generator possibly fuel in the oil?

Reply #19 – December 02, 2022, 10:59:32 am

If your generator does not have a quick drain, order one. They make changing oil really easy and fast. Just warm up the generator, pull it out on the tray and drain it.

With a coach this old, you are going to have to be able to do a lot of the maintenance yourself or have a big CC limit. Labor rates have gone up, up, up and while our coach has had no real problems in 14 years now but lots of little stuff, relay here, isolator there, an air bag or two.

Make sure the shocks are worn out as they normally last a very long time. Our 300SD has almost 500K on it and the Konis are in good shape as well as on our U300 with 120K miles. They don't wear out like the domestic shocks have a history of. Considering the age of you coach, the generator supply line does develop cracks and is responsible for the majority of the start-run a short time-stop that many have experienced.

Pierce

Re: generator possibly fuel in the oil?

Reply #20 – December 02, 2022, 11:12:29 am

Quote from: turbojack – December 02, 2022, 09:44:03 am

You will also be able to leave the old oil at the Walmart oil disposal station. Just get oil filter from a autoparts store vs a Walmart.

You said you are going South. If you don't change the oil hope you will not need the Roof AC's while traveling. It is going to be in the low 80's next week.

Going south yes, but only going to be in the motorhome for about four days. May have one day of driving where AC could be useful but it should be tolerable short term. After arrival, the coach goes back in storage till Spring most likely. The stay in FL will be in a condo, with some travel by air interspersed. Like they say, "it's complicated.". The main reason for driving the coach at all is to get Francisco (the cat) to FL. Planning on campground stays on the way down, so no overnights in parking lots and will have full hook-ups.

B.

Re: generator possibly fuel in the oil?

Reply #21 – December 02, 2022, 11:35:27 am

Quote from: Pierce & Gaylie Stewart – December 02, 2022, 10:59:32 am

If your generator does not have a quick drain, order one. They make changing oil really easy and fast. Just warm up the generator, pull it out on the tray and drain it.

With a coach this old, you are going to have to be able to do a lot of the maintenance yourself or have a big CC limit. Labor rates have gone up, up, up and while our coach has had no real problems in 14 years now but lots of little stuff, relay here, isolator there, an air bag or two.

Make sure the shocks are worn out as they normally last a very long time. Our 300SD has almost 500K on it and the Konis are in good shape as well as on our U300 with 120K miles. They don't wear out like the domestic shocks have a history of. Considering the age of you coach, the generator supply line does develop cracks and is responsible for the majority of the start-run a short time-stop that many have experienced.

Pierce

I will def get the quick drain if there's not one already there.

Agree on doing the work on the coach oneself. I had, until I closed shop, a mobile RV repair business for a few years. As my hourly rate was more than the shop that installed the new Konis, I considered it a savings. 😂 Nah...this time is was about speedy turnaround, short timing and tight schedules. Outsourcing this past work was just more expedient. And honestly, after hearing how 50% of the shocks were a bugger bolt-wise, the rate they charged became dramatically more reasonable. The bigger expense was the 8 shocks themselves. But turns out two were definitely shot and they all were the original Bilsteins from the factory, so it was time. And even though the shocks themselves were a high cost ticket, I did get a sale and free shipping. Would have rather paid what they sold for a couple years ago tho.

Bill

Re: generator possibly fuel in the oil?

Reply #22 – December 02, 2022, 01:42:51 pm

Bill you need to establish a new to you baseline of operation. I would simply change oil and watch the level. You could send a sample out to get analyzed and would no longer be guessing.
Scott

Re: generator possibly fuel in the oil?

Reply #23 – December 02, 2022, 02:35:50 pm

Down south covers a lot of area but I live in southwest Arkansas, 50 miles from the Louisiana line and I would be very surprised if an air conditioner is wanted before April. Way more likely wanting a heater.

Re: generator possibly fuel in the oil?

Reply #24 – December 02, 2022, 05:44:52 pm

Quote from: Dub – December 02, 2022, 02:35:50 pm

Down south covers a lot of area but I live in southwest Arkansas, 50 miles from the Louisiana line and I would be very surprised if an air conditioner is wanted before April. Way more likely wanting a heater.

41F this morning in Lyons, GA.

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