dunefreak Posted August 6, 2009 Share Posted August 6, 2009 Well my recent problem I had with my generator was NOT the carb. :beer_bang: How do I know this? I just bought a new carb and put it on and nothing has changed. Same problem still exists. So anyways, hopefully someone can help. Here's what it's doing. Earlier it fired up with a couple pops right after startup but it fired up. Then I turned both A/C units on and ran it for about 45 minutes. It ran great. Then it chugged for a split secoond a couple times, then about 10 seconds later it backfired then died. Now it fires up no prob with the usual pop or two right after startup, but as soon as I turn on the AC unit (or any other heavy load) it bogs and backfires bigtime. Here's is what I have checked... -oil level is good -fuel volume seems ok and fuel qaulity is good -fuel filters are both new -new carburetor -200 bucks and 2 beers later I'm still pretty pissed off eff yoooou 200 dollar carb for nothin Night drags trip ain't lookin so good! Quote Link to comment Share on other sites More sharing options...
80grit Posted August 6, 2009 Share Posted August 6, 2009 I really dont know but Ill throw up a couple ideas to check. Are you getting an error code (if its an Onan)? I had a similar problem last year where it would sputter and then die after 15 minutes. The blinking light was the error code. I looked it up and said it was a varying voltage. So I checked all the connections and the battery posts were oxidized. I cleaned them really good and the blades and that fixed my problem. By chance is the altitude adjustment wheel set for anything above 0 feet? Does the automatic choke lever move after it is running? Maybe its stuck in the on position? Quote Link to comment Share on other sites More sharing options...
wingnut Posted August 6, 2009 Share Posted August 6, 2009 That's what mine was doing when my fuel pump crapped out. What code is it throwing after it dies? Also, over on RV.Net, there are two onan guru's. When you post your problem, make sure you have your full model number, serial number and build date. I promise you will have an answer by the morning!!!! :B Quote Link to comment Share on other sites More sharing options...
SAND~~SNAKE Posted August 6, 2009 Share Posted August 6, 2009 battery and frame ground connections... Quote Link to comment Share on other sites More sharing options...
CaptNkllm Posted August 6, 2009 Share Posted August 6, 2009 Maybe it needs a programmer? :beer_bang: Haa J/K Pete.. Maybe Idle not correct? Check plugs? Does your AC run on shore power also? Maybe to much draw? How long before you tried restarting with AC? I read that you should give about 3 min or so for the AC to depressurize.. I am no pro but just guesses ... good luck man. Capt Quote Link to comment Share on other sites More sharing options...
dunefreak Posted August 6, 2009 Author Share Posted August 6, 2009 I really dont know but Ill throw up a couple ideas to check. Are you getting an error code (if its an Onan)? I had a similar problem last year where it would sputter and then die after 15 minutes. The blinking light was the error code. I looked it up and said it was a varying voltage. So I checked all the connections and the battery posts were oxidized. I cleaned them really good and the blades and that fixed my problem. By chance is the altitude adjustment wheel set for anything above 0 feet? Does the automatic choke lever move after it is running? Maybe its stuck in the on position? The error code is only 3 flashes which indicates "service required". (no sh*t lol) Altitude adjustment is set correctly. Auto choke lever works properly too. That's what mine was doing when my fuel pump crapped out. What code is it throwing after it dies? Also, over on RV.Net, there are two onan guru's. When you post your problem, make sure you have your full model number, serial number and build date. I promise you will have an answer by the morning!!!! :B I looked on there and didn't find anything, but maybe I'll post something up. Fuel pump makes sense. The genny runs great except at startup and under a load. battery and frame ground connections... both seem fine, checked them Maybe it needs a programmer? Haa J/K Pete.. Maybe Idle not correct? Check plugs? Does your AC run on shore power also? Maybe to much draw? How long before you tried restarting with AC? I read that you should give about 3 min or so for the AC to depressurize.. I am no pro but just guesses ... good luck man. Capt I pulled the plugs out and that's when I realized this thing had 2 cylinders. Who woulda thunk it! lol So this whole time I have been replacing one spark plug and one is probably still original. :freakin_nuts: I doubt that is the cause of it, but regardless, it will get 2 new ones. AC works fine when its plugged in. It has nothing to do with the AC. I know this because the pizzaz load affects it the same way. I also let the AC sit off for a while and generator run for a bit before turning it back on. Still did the same. I'm sure it started acting up more once the AC pressure was built up. Quote Link to comment Share on other sites More sharing options...
SAND~~SNAKE Posted August 6, 2009 Share Posted August 6, 2009 (edited) I have had problems w/ my invereter. Every thing was wacking out then I would put a load on it. Come to find out the cooling fan on the inverter was inop and causing the unit to overheat. Did you check the output voltage w/ your meter? Edited August 6, 2009 by SAND~~SNAKE Quote Link to comment Share on other sites More sharing options...
dunefreak Posted August 6, 2009 Author Share Posted August 6, 2009 I have had problems w/ my invereter. Every thing was wacking out then I would put a load on it. Come to find out the cooling fan on the inverter was inop and causing the unit to overheat. Did you check the output voltage w/ your meter? no, meter is at work Quote Link to comment Share on other sites More sharing options...
EY3BA11 Posted August 6, 2009 Share Posted August 6, 2009 should have called i would have grabbed mine from work and came over and drank a few brews with ya.. Quote Link to comment Share on other sites More sharing options...
SKINNER Posted August 6, 2009 Share Posted August 6, 2009 i no nothing about onans, but it alomst sounds like it vapor locking. runs fine for awhile then you increase the draw and it fails? maybe the increased draw is heating it up and there is a fuel line cookin a bit. just a stab in the dark. my generac has the square (ford courier) style pump, and they are common for just dropping volume, they always look fiine when you test them it seems, it comes and goes. i chased that problem for awhile before i figured it out on an old truck i had. dont know if they are the same on an onan , just throwing it out there. Quote Link to comment Share on other sites More sharing options...
dunefreak Posted August 6, 2009 Author Share Posted August 6, 2009 Thanks skinner. I checked the fuel line all the way from the generator back to the tank. It seems fine and doesn't seem like it is routed anywhere near a heat source that would cause it to vapor lock. I still think it is fuel issue and possibley a faulty fuel pump. I just need to find out a way to test it. I'm gonna bring home some test equip from work today and see if I can check it. Quote Link to comment Share on other sites More sharing options...
raspadoo Posted August 6, 2009 Share Posted August 6, 2009 Pete, have you replaced the fuel line? try running a temporary line if you have some laying around :freakin_nuts: Quote Link to comment Share on other sites More sharing options...
dunefreak Posted August 6, 2009 Author Share Posted August 6, 2009 Pete, have you replaced the fuel line? try running a temporary line if you have some laying around :freakin_nuts: I thought of doing that and running a line right into a gas can from the fuel pump inlet. But like I said, I checked the line and it looks to be in good shape and no links either. Quote Link to comment Share on other sites More sharing options...
bp-guy Posted August 6, 2009 Share Posted August 6, 2009 It sounds like an air in the fuel issue. But if you checked all your lines then you would have seen a craked fuel line. How about the carb gasket area? Did you try the brake cleaner trick to find an air leak when running? Start the generator and lightly spray around the carb where it mounts and listen to the idle for a change in rpm's. The fuel pump might have a pin hole in the diaphram also. Try having a small can with fuel hung above the carb outside the trailer and let it gravity feed into the generator. If it runs fine with just gravity feeding it then I would suspect the pump being faulty. Quote Link to comment Share on other sites More sharing options...
lvnalolife Posted August 6, 2009 Share Posted August 6, 2009 Found this site too! Couldn't hurt to run it by them. Onan@JustAnswer.com Quote Link to comment Share on other sites More sharing options...
bp-guy Posted August 6, 2009 Share Posted August 6, 2009 That site is a pay for answer site. I just checked it out. Quote Link to comment Share on other sites More sharing options...
dunefreak Posted August 6, 2009 Author Share Posted August 6, 2009 I talked with Ken @ Johnny Walker this morning. He is leaning towards it being a valve issue- either sticking or carboned up. I am going to check a few things tonight. Thanks again Terry for putting the call out. Quote Link to comment Share on other sites More sharing options...
wingnut Posted August 6, 2009 Share Posted August 6, 2009 It sounds like an air in the fuel issue. But if you checked all your lines then you would have seen a craked fuel line. How about the carb gasket area? Did you try the brake cleaner trick to find an air leak when running? Start the generator and lightly spray around the carb where it mounts and listen to the idle for a change in rpm's. The fuel pump might have a pin hole in the diaphram also. Try having a small can with fuel hung above the carb outside the trailer and let it gravity feed into the generator. If it runs fine with just gravity feeding it then I would suspect the pump being faulty. This is a good way to check it. I ran a line to a 5 gallon jug that was sitting under the geni and it ran all day. Being a pull pump, it would suck the fuel a short distance no prob. Sucking the fuel through 35 feet of fuel line, no bueno! Also, is the pump real quiet when you prime it? A good pump taps like a mofo when it priming........ Quote Link to comment Share on other sites More sharing options...
dunefreak Posted August 6, 2009 Author Share Posted August 6, 2009 This is a good way to check it. I ran a line to a 5 gallon jug that was sitting under the geni and it ran all day. Being a pull pump, it would suck the fuel a short distance no prob. Sucking the fuel through 35 feet of fuel line, no bueno! Also, is the pump real quiet when you prime it? A good pump taps like a mofo when it priming........ Is there an echo in here? LOL I thought of doing that and running a line right into a gas can from the fuel pump inlet. But like I said, I checked the line and it looks to be in good shape and no links either. Quote Link to comment Share on other sites More sharing options...
raspadoo Posted August 6, 2009 Share Posted August 6, 2009 Just to be sure I always slap a clear inline filter on the primary side of the carb, if the fuel line is cracked in the right spot it will suck air and not leak... Hope it's not a valve issue. :freakin_nuts: Quote Link to comment Share on other sites More sharing options...
CaptNkllm Posted August 6, 2009 Share Posted August 6, 2009 I pulled the plugs out and that's when I realized this thing had 2 cylinders. Who woulda thunk it! lol So this whole time I have been replacing one spark plug and one is probably still original. :freakin_nuts: I doubt that is the cause of it, but regardless, it will get 2 new ones. Lol ... Sry I had to laugh out loud... I did the same thing.. why wouldnt they tell you when you buy only 1 spark plug that it takes 2? Capt Quote Link to comment Share on other sites More sharing options...
bp-guy Posted August 6, 2009 Share Posted August 6, 2009 Is there an echo in here? LOL But you did it at the pump- I suggested you do it from a gas can straight to the generator with about 2 feet of fuel line. this way you eliminate all the other parts of the supply to the generator. oh yeah EFF YO ECHO!! :B Quote Link to comment Share on other sites More sharing options...
dunefreak Posted August 7, 2009 Author Share Posted August 7, 2009 Well I checked a bunch of stuff tonight. 1. checked the valves. None were sticking or seemed to be hanging up. They were on the loose side so I adjusted them. They seem quieter now, but no change with the backfiring under load. 2. Fuel pump is flowing plenty of fuel. I even ran a fuel line from the inlet of the pump to a gas can and also removed the line on the carb to watch the fuel and it flows plenty. 3. Most of the time when the A/C or any large load is turned on, it chugs & backfires immediately. When it does this I spray carb cleaner in the carb and it only makes it worse. I am pretty convinced it is not a fuel problem or lean condition. Sometimes it will run one ac unit with no troubles at all. It's hit or miss. 4. I double checked all grounds and connections. I got nothin. It seems like it might even be electrical at this point. If it was a fuel issue, it would start to surge or at least wait until the carb bowl went dry then backfire. It does it as soon as you turn the A/C on. It's like the ignition is almost being draw down or grounded when there is a large load applied. Quote Link to comment Share on other sites More sharing options...
wingnut Posted August 7, 2009 Share Posted August 7, 2009 Eff it for now and bring a nice extension cord!!! Quote Link to comment Share on other sites More sharing options...
dunefreak Posted August 7, 2009 Author Share Posted August 7, 2009 Eff it for now and bring a nice extension cord!!! Thats not even an option. A/C won't run off an ext cord. Especially both units. (50 amp svc) I'm not too worried about it. Temps don't seem too bad this weekend. Cold beers, a couple fans, and enough water for a few ice cold showers. Quote Link to comment Share on other sites More sharing options...
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