Forum Discussion

RV_Hero's avatar
RV_Hero
Explorer
Jul 02, 2016

Onan generator Carb cleaning, no need to replace carb.

putting a T in the line feeding the carb, then I can hook a hose to it with carburetor cleaner , coming from a bottle held higher then the generator. This way I can put a concentration of carb cleaner directly into the bowl...run for a minute shut off and let it sit for 30 minutes so it removes all the gum and gunk from inside the carb.bowl, then restart,,, when done reattach gas line...what do you think...this would saved over $700 cost to replace carb.....This cure would save everyone with these generators a lot of money.....Call me RV Hero......one note I used Sta-bil treatment in my gasoline. research that fuel is pumping has shown me that it is in the carb. a little cleaner in the gas line makes it start and run for a few minutes. needs a bigger dose.

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Day 2,,, I did the concentration trick filling the carb and running it on B12 and seafoam, let it soak about 20 minutes ran it and did this 5 times,,,then filled it again let carb take only the mixture...out of a plastic peanut butter jar... then let it soak for 5 hours....then started again,,reattached gas line and put everything back to normal...it runs but rough idle...I need to choke it to start it...now I am going with the gas filter and fuel pump switch...maybe not enough gas..when I checked the gas flow before I started it pumped but small stream.....I do believe the inside of the carb is clean...from all the carb cleaners...does anyone know how much gas should pump? Thanks
Class C
  • romore's avatar
    romore
    Explorer II
    Jul 02, 2016
    It likely won't restart, any mung loosened will clog the jets. There is really no need to replace a carb that isn't severely worn, damaged or corroded and no amount of cleaning will cure that. Careful disassembly and cleaning should solve most problems, just hope you don't need a kit as Onan is very proud of those too.
  • gbopp's avatar
    gbopp
    Explorer
    Jul 02, 2016
    I thought that's what most people do when using Seafoam to clean the generator carb. It seems like common sense.
    Or, maybe it's just as easy to remove the fuel line and attach the cleaner line.

    Maybe I'm missing something?
  • j-d's avatar
    j-d
    Explorer II
    Jul 02, 2016
    You've made an A-Dapter that makes it much easier to do what has worked for several of us: Remove Fuel line to Carb. Pour the cleaner into Line. Start genset and shut down to let it soak. Be sure to use fittings that won't leak while you aren't carb cleaning. A similar trick is to dose a gallon of gas heavily with cleaner (many like Berryman) and fuel the genset with that mixture.

    If you have an ONAN 4KY genset, those carbs have tiny passages that are laid out so you can't "tag wire" them for cleaning. So... If you've got a fix and it works, Good On You.

    I met a sport fisherman named Joe from North Carolina. He'd drive his Class C to FL several times a year to fish. One day he was running his generator and I commented how well it started and how smooth it ran. Joe said he puts StaBil in every drop of gas that goes in that 55 gallon tank on the E450. Even on those 700 mile road trips, I asked. And Joe said Yes, Every Drop. So now, j-d does like Joe. I had to replace a carb a few years ago and I don't want the trouble or expense again. Been good now for several years. I still exercise the genset, but now it always starts, always runs well. Just like Joe.
  • Sam_Spade's avatar
    Sam_Spade
    Explorer
    Jul 02, 2016
    gbopp wrote:
    I thought that's what most people do when using Seafoam to clean the generator carb.


    If you practice a little good preventive maintenance......and use a good carb cleaner like Berrymans B12 Chemtool or Gumout.....instead of an over-priced fuel stabilizer marketed as a cleaner, like Seafoam, simply putting the required amount IN the gas should keep you running fine.

    Seafoam really isn't good if you neglect things until there is a severe problem. B12 is about as good as it gets but in really severe cases even manual cleaning can't get to the tiny passages that get blocked with what sometimes resembles concrete.

    $700 seems WAY too high for a simple carb replacement.
    Look for some different Cummins dealers.
  • F1bNorm's avatar
    F1bNorm
    Explorer
    Jul 02, 2016
    It amazes me how well SeaFoam works. I wait until my MH fuel tank is down to its last third of a tank (enough that I know the gen can draw fuel) and dump in a can of SF. It works great on my little Honda stuff, too.

    I did learn from the Honda techs, the best fix for occasional use, is to drain the carb bowl before storage. I wish the Onan had a drain.

    Norm
  • gbopp's avatar
    gbopp
    Explorer
    Jul 03, 2016
    Sam Spade wrote:
    Seafoam really isn't good if you neglect things until there is a severe problem. B12 is about as good as it gets but in really severe cases even manual cleaning can't get to the tiny passages that get blocked with what sometimes resembles concrete.

    I actually wanted to say, Seafoam or the cleaner of your choice. Obviously, I didn't. :)

    I have not tried Berrymans yet. But I will. Thanks.
  • edatlanta's avatar
    edatlanta
    Explorer
    Jul 03, 2016
    j-d wrote:
    You've made an A-Dapter that makes it much easier to do what has worked for several of us: Remove Fuel line to Carb. Pour the cleaner into Line. Start genset and shut down to let it soak. Be sure to use fittings that won't leak while you aren't carb cleaning. A similar trick is to dose a gallon of gas heavily with cleaner (many like Berryman) and fuel the genset with that mixture.

    If you have an ONAN 4KY genset, those carbs have tiny passages that are laid out so you can't "tag wire" them for cleaning. So... If you've got a fix and it works, Good On You.

    I met a sport fisherman named Joe from North Carolina. He'd drive his Class C to FL several times a year to fish. One day he was running his generator and I commented how well it started and how smooth it ran. Joe said he puts StaBil in every drop of gas that goes in that 55 gallon tank on the E450. Even on those 700 mile road trips, I asked. And Joe said Yes, Every Drop. So now, j-d does like Joe. I had to replace a carb a few years ago and I don't want the trouble or expense again. Been good now for several years. I still exercise the genset, but now it always starts, always runs well. Just like Joe.


    I use StaBil Marine formula in every drop of gas that goes into my Onan and only use ethanol gas if it is the only gas available. If I have had to use ethanol gas I ALWAYS run the tank dry and fill with non-ethanol gas. I run it on the first of every month for an hour under load and NEVER fail to do this. It has 352 hours on it now and has never failed to run and provide electricity when I need it.
  • Sam_Spade's avatar
    Sam_Spade
    Explorer
    Jul 03, 2016
    edatlanta wrote:

    I use StaBil Marine formula in every drop of gas that goes into my Onan

    I run it on the first of every month for an hour under load and NEVER fail to do this.


    Given your good practices with the fuel, I think your obsession over not using ethanol is a gross over-reaction.

    Ethanol is NOT the work of the devil.
    Some areas of the world have been using E90-E100 for decades.
  • klutchdust's avatar
    klutchdust
    Explorer II
    Jul 03, 2016
    Sta-bil goes in all my vehicles and each fuel can that is used for small engines and haven't had a problem. I use Marvel mystery oil in my diesels along with a fuel lubricity product due to the low sulphur content in today's diesel fuel. I have used sea foam, best price is walmart, and after using it the rough idle in my Jeep stopped, the 85 mercedes diesel idles better and daughters stalling Suburban doesn't stall anymore when turning on the air conditioner, you decide.


    After reading Sam Spade's comments i researched Berrymans and Seafoams MSDS sheets and I was quite surprised with the difference in ingredients. I have always

    had a good response with sea foam but I think my choice for my gasoline engines has changed.
  • Bobbo's avatar
    Bobbo
    Explorer II
    Jul 03, 2016
    Sam Spade wrote:
    gbopp wrote:
    I thought that's what most people do when using Seafoam to clean the generator carb.

    Seafoam really isn't good if you neglect things until there is a severe problem.

    SeaFoam is wonderful stuff. I have a 24hp riding mower that got to where it would not start without starter fluid. It would not run except on choke. It would spit and misfire constantly.

    I googled those symptoms and read it was a clogged carburetor. I added SeaFoam at twice the recommended concentration, and drove it around for 30 minutes, then I let it sit for 2 weeks. When I mowed the yard after 2 weeks, it was running MUCH better. Would start without starter fluid, and would run without staying choked. It would only spit every once in a while.

    I let it sit another 2 weeks, and it now runs like a sewing machine. It runs as well as it did when new. No spitting or misfiring at all.

    SeaFoam is wonderful stuff.

    F1bNorm wrote:
    I did learn from the Honda techs, the best fix for occasional use, is to drain the carb bowl before storage. I wish the Onan had a drain.

    I am seriously considering putting a gasoline rated shut-off valve in the ONAN fuel line, then use that to kill the generator every month when I exercise it.

    I normally have a hard time starting the ONAN. When I exercised it in May, it pulled the fuel too low and died of fuel starvation. When I exercised it in June, it kicked right off! I couldn't believe how easy it was to start, just because it had no fuel in the carb for that month.

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