Generac Generator Dropped a Valve - Will It Run and Make Power Again?

hey guys welcome back so to today we're working on this gener gp6500 uh this one I found on Facebook Marketplace and it was given away for free and I think some of you might have spotted the problem when I pulled this one up on the lift uh but the Piston not doing so well there is a pretty big hole punched in it and like that this engine absolutely will not run so you know the story I'm told on this from the owner was that you know she was running machine when it locked up so she had a friend take a look you know he's the one that disassembled it and was greeted by this damage here and it's not just the Piston actually the head is damaged pretty bad as well the exhaust valve actually broke off and that's what got smashed between the piston and the head so the head is damaged obviously the exhaust valve is broken and missing and likely the intake valve is bent as well so I would say the head is a total loss uh the Piston is definitely a loss and potentially the whole engine anyway in my case not too worried about the engine although this one might be rebuildable you know I think that will be for a future video because about a year ago I did pick up a GP 5000 you know that one had a bad generator head but the engine I believe to be good and it's an exact replacement for the failed engine so I say we do the easy thing let's get the generator off this machine we will do an engine swap and hopefully make quick work of this and get this machine back up and running again so let me get you set up a little bit better and get going on this actually before I split the generator and the engine I do want to get the oil out of it and actually level this Frame there is supposed to be a rubber foot on each leg and we're missing the one on the other side so I'm going to get that replaced we'll get the machine leveled out you know we'll get the oil drained out then we'll start the disassembly despite the damage to the top end I'm thinking the bottom end of this engine likely isn't in too bad a shape I mean there was definitely parts of the Piston that went to the bottom end but this engine would have stopped running immediately and uh yeah this I think was left out in the rain unfortunately that is all water coming out of here so I take back what I said about the engine might be too late to save this one I'd say the odds of doing a future rebuild video on this engine just went down quite a bit you know even though I think the bottom end likely survived the trauma that that happened up above the water may have done the bottom end in there are quite a few parts in there made out of steel like the ball bearings the crank the cam and the counterbalancer that don't do so well with water they may have rusted up so you know once we get the generator off I will pull the bolts on the end cover we'll pop that off and take a quick look inside to see if there's any chance of a future rebuild this one's a little bit different I don't see them wired like this often uh usually there's three or four wires coming from the stator in this case we have four you know the red is leg one black is leg two and then the neutral is usually on a third post and in this case there is no third post they actually ran the neutral right to the frame and they've also connected the ground and the neutral that run up to the control panel so this is a bonded neutral system which is fine when you're using it as a portable generator but if you're wiring this into your house that Bond should be broken and usually the way you do it is by moving the neutral wires coming from the stator as well as the one that goes up to the control panel you know moving them off this post and putting them somewhere on their own and yeah this one there's no option to do that anyway to get the stator off we do need to disconnect everything remove the AVR remove the brushes and of course remove a bunch of bolts and at that point we can use a puller to separate the ball bearing from the in-housing right I've lifted up the stator higher than it needs to be really just to get these mounts out you it's a lot easier to remove the generator head and reinstall it without these getting in the way [Music] [Music] just a word of caution when using a puller this end housing it's not very strong it's very easy to break so when you put the Jaws on don't put one where the brushes go because that is the weakest point and sometimes you can actually break the seal without even putting a wrench on the puller you know in this case I think we do need a wrench but don't apply much force you know if it doesn't come off then you know step back try something else you know a lot of times the stator gets stuck in the bell housing or the ball bearing gets stuck in the end housing so if it's not coming out don't apply too much force you know kind of tap around here with a rubber mallet spray some PB Blaster in here and just work at it until it breaks free and in this case this one's coming out without a fight so I'm going to try to use the rotor bolt to shock the rotor off the tapered shaft so you know I've driven the bolt most of the way back in and the idea is you want to strike it pretty hard and hopefully that shock will release it from the tapered shaft if it doesn't then we can go to plan B which is using water to build hydraulic pressure but let's try this uh this is a pretty easy thing to do now you do have to watch out you don't want to miss the bolt you're going to destroy the rotor and of course if the bolt gets struck too hard you might actually pretzel it so you know take care you know if it doesn't work don't go crazy there are other ways to get this off I think that might have done it [Music] all right let's have a look I tilted the engine back you know although the oil was drained there is usually enough left to make a mess so by tilting it back we should keep what's left inside the engine not bad I think we got pretty lucky on this one it doesn't look like the water caused any damage so I don't think it was in there for very long you know everything looks to be in great shape and surprisingly the Dipper you know that is still intact usually that is the first thing to break when shrapnel starts flying around yet that is in good shape so I'd say there's a good chance that the connecting rod is actually good you know as far as the cover go es also in good condition these bearings they are nice and smooth Governor gear is intact and the cylinder also in excellent condition plenty of crosshatch somehow no damage so yeah I would say for sure you know this engine is rebuildable if we can get a new head and a new piston anyway let's set this aside and we'll start putting the machine back together I don't think I showed you this before but there were only 64.2 hours on the clock when that other engine dropped a valve and it self-destructed so you know that engine looked pretty much brand new because it was you know this one doesn't look as good we have a bunch of dust and aluminum oxide you know a fair amount of rust on the blower housing you know the carb I'm sure has issues I actually haven't run this engine yet so likely we're going to have to go through that you know we will double check the valves as well but before I do any of that let's just finish getting the power head on and then we'll do some checks and if everything looks good we'll try it out I'm just going to take a second get these slip rings cleaned up while we have easy access and just be mindful of these connections from the rotor to the slip rings they're easy to break so you don't want to hit it with the scotch Sprite I've got a wrench on the flywheel nut on the other side of the engine so that'll hold the crankshaft still and allow me to torque this to 30 ftlb now one thing to note I always get comments about this shaft because when the engine's running you know it's shaking back and forth and a lot of that has to do with the fact that the bolt has some Play Between the bolt diameter and the in race of the ball bearing also the washer has play as well so when I torque this down it usually goes to one side and of course when the engine's spinning you know it looks like something's wrong but that unfortunately is by Design so it is nothing to worry about for [Music] so now that the rotor and the stator are both installed you want to rotate the engine and just make sure it rotates without issue you know in this case I have the spark plug removed so they really shouldn't be any resistance you know if the engine binds or you hear scraping down in the generator head then something's not aligned right and likely you should just uninstall the whole thing and try it again until you're able to rotate the engine freely you know in this case we're good so let's get the wires reconnected for for [Music] I just rotated the engine the exhaust valve is open so when the exhaust is open we can check and set the intake and there's a tiny bit of lash but it's pretty close to zero that's likely less than 2000 of an inch but let's just double check where it's at the intake take is supposed to be 6,000 and the six does not fit it is plus or minus a th000 but the five also does not fit neither does the four and the three fits so yeah the intake definitely is tight it needs to be adjusted so let's rotate the engine again until the intake is open and we'll see where the exhaust is at all right the exhaust it should be 8,000 of an inch plus or minus a thousandth and the eight does not fit let's try a six does not fit how about a four does not fit three doesn't fit at 2000s doesn't fit and this is the smallest gauge I have 1 and half thousand so yeah that exhaust it's almost at zero and the intake isn't far behind so let's adjust these to 6000 and 8,000 all right the a fits pretty good so we'll snug that up and double check it cuz a lot of times when you tighten it up you know it takes all the slop or the play out of the threads and then it does close up so actually good strategy against that is to actually set it a little bit larger so we'll actually aim for a nine and when we tighten up this nut chances are it's going to be an eight or even a little bit less the eight feels pretty good and the nine doesn't fit so the exhaust is good so let's rotate the engine and set the intake all right right there the six feels pretty good so we'll just snug up this lock nut and double check and one question I always get asked in the comments is why do you even have to adjust the valves you know were they set wrong at the factory and the answer is no although I suppose it's possible but it's a normal process you know as the valve opens and closes it wears into the seat on the cylinder side and over time that valve kind of recedes into the head and as it does that it closes up the gap between the stem and The Rocker until you get to zero clearance and at that point you lose compression you know your car does the same thing the big difference is most cars made today have hydraulic lifters and those automatically keep the clearance where it should be at anyway this one I think we're all set the six feels pretty good and seven does not fit so we can put the cover back on and move on going to pull the carburetor and just take a quick look inside you know I'm sure it needs to be cleaned [Music] I see one problem right away the choke plate is completely missing so you know although the carb would still work you know starting it would be really tough so you know I have another carb I actually have a bunch of other carbs that I know work so I'm going to grab one of those instead and even before I do that let's just swap the blower housings real quick and then we'll put a different carb on that is complete and should run this engine well this generator doesn't have a switch up on the control panel it's just right here on the side of the engine so I've connected this wire which is just connecting over to the Block it's a source of ground when you turn this to on it sends the ground through onto the coil and that ground will kill Spark park now we also have the low oil system which also needs to have the ability to shut the engine down so the other connector just goes right here so that way you know either the switch here or the oil sensor can shut the engine down so this is the carb here I'm going to use this one is brand new and was sent to me by Roger so thank you Roger for that this should be a direct replace bement and I think the biggest difference here is that this one does have a fuel solenoid uh the original one did not luckily these are normally open so they don't need to be powered for the engine to run so the fact that this machine can't control the solenoids shouldn't be a big problem anyway before I get the carb on I actually want to swap out this spring it is damaged so I'm going to steal the spring from the blown engine that going to leave the airbox off for now we'll do a quick test like this just make sure that this engine sounds good I haven't heard it run you I don't know 100% that the generator makes power you know I'm assuming that it does since someone was using it when the engine blew so yeah let's just torque this down real quick we'll feed it some fuel to a quick test make sure everything's good let's just check the oil real quick and we are pretty overfilled so that has me concerned maybe we have water or fuel in there so I hate doing oil changes before running a machine but in this case might be called for especially if we have water down there so let's just change the oil real quick and then we'll try it I'm really hoping this doesn't have water in it okay good it's actually just overfilled with oil doesn't smell like fuel either so yeah I think we're okay so we'll just let a little bit out should be good it's the Moment of Truth we are all fueled up got a light plugged in and turned on and we will turn the ignition switch on pull it over and hopefully we hear a good running engine and that light turns up on now I did back the spring tension off a little bit so it's going to run slow but I think it'll still be fast enough to see and hear what we need to all right choke is on ignition's on not too bad started first pull uh the engine sounded really good and we're making power you know surprisingly the engine speed was also close to 60 HZ 122 volts so overall I'm pretty happy with the way this thing turned out and I guess the only issue was the carburetor it was running lean you know I tried to turn the choke off a few times after starting the engine and the engine started to Surge so you I ran it at partial choke for about 30 seconds and I was finally able to turn it off so I think we might be okay you know adding the airbox is only going to Rich things up so I want to do that first and if we're still lean we can always drill that pilot Jed out a bit anyway before putting that airbox back on let's get that oil changed now while it's hot for I'm pretty sure I just found the cause of the other engine failure you know initially I had assumed it was a quality control issue and well I don't think that's the case anymore you know I just pulled this pilot jet the one from the new carb that we just tested to measure it up and the thought being you know instead of drilling this out maybe I should just swap it out with the pilot jet from the carb that was originally on this engine the one that's missing its choke plate so I measured up that pilot and found that it was actually smaller so putting this over here would make things worse so then I grabbed the carb from the blown up engine and that's when it hit me as far as the cause of the failure you can see it right here I'm sure some of you have spotted it already but what's the one thing I always say when I put carbs together I say that this is the idle set screw and most generators do not idle so when you put the screw back in really the only purpose of it is to hold the pilot jet down you only want to turn it in until one or two threads poke through and if you drive it all the way in like this one is it's going to cause the engine to over rev and the engine's going to self-destruct and that's exactly what somebody did here so like this I'm sure the engine was running an excess of 5,000 RPM and at those speeds you know the valves would have started floating meaning they couldn't close fast enough and every time the Piston came up the piston started crashing into the valves and eventually caused one to break off so yeah this issue was not quality control you know it was self-inflicted by someone who didn't understand the purpose of that little plastic screw yeah I'm thinking instead of trying to drill that other carb out let's just fix the carb that came on the engine so even though this choke plate is broken and actually the shaft is as well this part is removable and I have lots of Clone carbs so I'm sure we can find a donor but before we fix that let's just open up the carb and see if it's worth fixing yeah it's pretty clean in here not much in the way of debris so I actually think this carb would run as is but there is a little bit of crustiness so we'll clean that off maybe with a wire brush and some carb spray we'll fix that choke then we'll try this one out I'm going to use this one as the donor carb they are actually made by the same company so I'm thinking the throttle plate should move over without much issue and even if it was a different brand usually things are fairly standard so actually I'm going to leave most of this carb together I just need to get the choke lever off you know we can pull that plate out and then once the plate is removed we should be able to remove the shaft and transfer it over so the big issue here is that this piece of plastic is kind of sandwiching this together and there's some raised sections here which lock this plate in and it's not really designed to be removed you know it's meant to be installed and that's pretty much it so trying to remove it might might break it if I'm not careful so right now I've got something wedged in there to kind kind of open up or separate that plastic from the plate so we might be able to pull it out now and no putting this together should be a lot easier than taking it apart cuz it was really only designed with putting it together in mind I think the biggest thing is just to make sure you get the orientation of the plate correct that should do it so this carb now has a working choke I just went through the whole carb and didn't find any issues there were no blockages so I think this one has has a good chance of running the machine so I'm going to bolt this one on real quick and I guess we'll find out so we'll just turn the idle set in so that couple threads poke through and that's all you need so we're just about there just got to add the choke lever and we'll be ready to go new carbs out old carbs in and it's been fueled up so let's give it a try I think we have a winner with the original carb you know this time I was able to turn the choke off right away it did surge a little for the first second or two and it quickly worked itself out so you know I think we're at the point where we can get the airbox on and roll this thing outside we'll put it to the test and see if it can pull its rated load of 6,500 Watts for [Music] I've got everything set up and ready to go so I'm going to get the engine started we'll let it warm up while it's doing that we'll double check the voltage and the Hertz and then we're going to bring on a load you know we'll bring it up to about 3,000 Watts double check the outputs and the power quality and then we'll bring it up to the max of 6,500 watts and see how it does that's so far so good but without a load the THD has at about 5% which isn't too bad and the side wave actually looks pretty good so let's bring on a load of 3,000 Watts that's 2,000 3,000 let's say that did not go as planned you know it started first pull the engine speed was a little slow so we brought it up to 612 Hertz then we put on a 3,000 WT load you know things seemed to be going fine until they didn't you know the engine abruptly started to backfire and shut down and while doing so it sent some power surges the oscilloscope will no longer turn on the load bank did not cool down properly so we could have issues there as well so I'm going to try to restart it and if it doesn't restart we will dig in and figure out what went wrong so it's showing no signs of life I'm just going to pull the yellow wire that's the one from the low oil system that can kill spark as well as the switch but the switch is on so let's try it again and we get no signs of life so I'm going to get the tank off that way we can get better access to the spark plug we'll get a tester on there and see if we do or do not have spark yeah this is kind of hard to show you in the bright light but let's pull the engine over and see if we see a spark jumping that Gap and no I don't see any spark so we have a bad coil look at that the new choke broke that shaft broke so I don't know if it was the backfire that did that that's very odd [Music] for [Music] m [Music] [Music] going to use the carburetor from the blown up engine I back to that idle set screw pretty much all the way out there's only a thread or two in there now so it shouldn't over rev and I did take a look inside the bowl it looks really clean so I'm thinking this one has a chance of running all right let's give this a try we are all back together hopefully it starts and no more surprises so far so good you know without a load we are at about 5% THD so let's bring on a 2,000 WT load another th000 wats so we're back at 3,000 THD jumped quite a bit about 16% but it is holding so let's swap 1,000 for 2,000 no issues 5,000 whoa that's not good so I'm going to let this cool down not sure what would be causing that I've got to be honest this one has me a little a little bit stumped we have a new coil we have a new carburetor yet it's still backfiring under a heavy load so you know potentially the low oil system is messing up spark maybe we have a timing issue or maybe we have a bad plug so I'm going to swap that out real quick and we'll try it again the plug doesn't look bad bad but you never know [Applause] all right so far so good THD like before about 5% let's bring on 3,000 ws and so far so good at about 16% THD so we'll give this a minute and then we'll try bringing it back up to the max of 6,500 Watts it's been a couple minutes no issues to report so let's take off 1,000 swap it with a two so now we're at 4,000 watts we'll go up slowly 5,000 5500 6,000 seems to be running fine so let's swap that that for a two and now we're back to 6,000 and now 6500 wats yeah it's doing it the THD it's about the same 16.7% [Music] [Applause] who would have guessed it was just a bad plug all along so this time I had no issues pulling the rated load of 6500 watts and I'm kind of second guessing myself as far as what I did you know when I swapped that coil you know I didn't think I saw a spark and the engine wouldn't start you know once that new coil was in there the engine ran just fine but it didn't fix the problem under heavy load and now with the new plug that problem is sorted too so yeah sometimes it is a simple fix if your engine's running poorly you know swap the plug it could be that easy so I hope this video helps someone thanks for watching oh

Channel: James Condon

Views: 71,078

Keywords: 389cc, 420cc, Alternator, Backfiring Under Load, Backfiring, Bad Spark Plug, Broken Choke Plate, Broken Valve, Clean Slip Rings, Dropped Valve, Engine Swap, Exhaust Valve, Fixed, G0076700, GP5500, GP6500, GP7500, Generac, Generator, Hertz, Hole in Piston, Honda Clone, How To, How-To, Ignition Coil, Load Test Fail, Load Test, Low Oil Sensor Bypass, No Spark, Overrevving, Repair, Small Engine, Spark Plug, Troubleshooting, Valve Adjustment, Water in Engine, Water in Oil, Will Not Start

Id: TGV2atGmkMA

Length: 61min 0sec (3660 seconds)

Published: Thu Apr 18 2024