Riding Mower Bogs Or Dies Under Load, Easy Diagnosis / Repair When There Is No Power Or Runs Rough

hey there welcome back this morning we have a pool and pro 700 eex we're working on customer brought this in and said it wouldn't stay running whenever they let off the brake well the problem was the seat was in such bad shape that the seat wasn't hitting the safety switch random rag on there now when you sit on it it'll fire up problem solved right well partially problem is when we start it up doesn't sound quite [Music] right now with a trained ear that sounds to me like it's running on one cylinder people will think this problem has something to do with the carburetor they'll think this problem has something to do with the gas a lot of the times uh sometimes it does sometimes it doesn't now if your mower is running for a while and then shutting off check your fuel supply check your fuel line coming from the back of the tank a lot of times it's actually the pickup coming from the back of the tank where the fuel line goes in where it pulls up it'll grab pieces of grass that's falling down in here stuff like this and as it comes up and around this Bend it'll get caught so the grass will get caught at this corner and it'll allow suction but it won't be fast enough to keep up with the fuel supply of the mower so your mower will keep dying out one of one of the most common things that happens with mowers dying out uh after 15 or 20 minutes sometimes takes up to 45 minutes or a or an hour depending on what mower it is and the situation what's clogging it things like that this sounds to me though like it's running on one cylinder it doesn't just have low power um because of a fuel issue or a carburetor issue I will show you how to test that and confirm that it is an issue like this first we'll want to take a look at each cylinder independently so this has the Briggs v twin on it it's a 26 horsepower intch they've got some known issues but they are a relatively good engine in my opinion to test each side independently basically we will want to pull a spark plug wire off and see if the opposite side will run without it you've got a spark plug here and a spark plug on the other side if you pull the wire out and hold it over to the side now people will tell you to ground out the spark plug and things like that it's not going to matter for testing purposes if you leave that thing off for just a second the mower fires up fine which means that the opposite cylinder over there is working properly that means that the valves are working on it that means that the spark working on it and that it is getting compression because we completely took this whole side of the engine out of the equation let's check this side well I got a nice big pop out of it but didn't get anything other than that this side has got something going on the other side seems to be okay at least that's our Diagnostics currently let's check the spark on this looks like I'm getting good spark on this side that's a good sign now we know we're getting fuel we just got that good pop out of it I'm going to take this spark plug out anyway looks a little bit strange wow they really had that in there oh yeah okay so that's a gold spark plug Briggs and Stratton you can tell it's been in there quite a while but obviously hasn't been doing anything the tip is basically brand new there's a bunch of oil and stuff like that on it we know we're getting spark uh we know that we're getting fuel because the other side's getting fuel the only thing left on this is going to be compression now there is oil and everything all around and even up underneath if you look under there and you see a bunch of oil in between the fins uh where the head gasket meets there's a head here that attaches to the block if you see up under there that there's oil in between those fins then you know that the head gasket is blown on this and that could be one reason that your mower is not firing it's just blowing all the compression out there and it's not enough to run on this cylinder otherwise we could have a bent push rod or we could have a stuck valve we're going to open the valve cover and see what's going on from here now if you've got a compression tester you could throw a compression test on it it's not even moving there's nothing on the needle at all question is is the Piston moving we know we don't have compression even if you didn't have a compression tester we'll show you how to check it by just opening the valve cover but let's turn this over so the Piston is moving up and down we know this cuz I've got the screwdriver right on the top of the piston and it's moving in and out as I turn the engine over that means that one of these valves is likely stuck open causing this issue that's just the evidence from the pop that we heard and the zero compression with the Piston moving up and down even if the head gasket was blown out pretty bad you'll still get something and a lot of times you'll hear a whooshing noise coming from it I told the customer what exactly was going on kind of what we were going to do and we got a new seat on order seemed like it was on back order a couple weeks if I remember correctly we're not in any hurry to get this this thing done right this second I did want to diagnose the running issue see exactly what's going on now with our top valve in which is our intake valve our exhaust valve is still in it's not interesting so this valve is not coming back out at all what it looks like has happened is that something has allowed our middle rocker piece to turn on this valve and keep this valve from coming back out now these push rods look okay the push rods come in and out you've got one at the top and one at the bottom but over here with that turning sideways it doesn't allow this exhaust valve to pop back all the way out these should come back to the same to the same levels when they come back and they're not the exhaust valve stays right where it is it gets pushed in just for a second and otherwise it stays right where it is so it's pushing in and then comes back out just that tiny bit that's not enough to seal it that valve still still open what I'm going to try to do is get this push rod off or out of there just by pushing that valve in and it po back out to the level it should be so that is definitely bent it bent the push rod when that happen but why did this happen why did that turn like that did somebody install this incorrectly because I've never seen anything like that happen before yeah so that is locked down in the position that you put it in and this was tight it was not loose there's no way that this was not installed like that the last time somebody had this open somebody tried to fix it and reinstalled it incorrectly going to get a push rod and see if we have some different rocker accessories and get this thing put back together before we go any further I'm going to blow all [Music] the make sure nothing gets down in I've also cleaned off the old gasket material from the valve cover and cleaned it all up ready to go back on no residue or leftover gasking along here at all if you get into here and you notice bent push rods and there's not an issue like somebody's been in messing with it somebody's installed it wrong you know when somebody installs something like this and it's supposed to go the other way that's not going to turn out good the additional the original screw was kind of stripped on the end so we replaced it with one that has good threads and then we also got another piece of The Rocker to make sure that one wasn't too bad if you get in here and notice bent push rods or you notice uh something a miss or any of these loose if your stud is loose here you want to address that make sure the threads are not stripped out make sure when we tighten this down it goes back to a good torque spec make sure it's tight the valves when they go in and out these should both come back out the same amount if this one is not even with this one when they're both released when there's no pressure on them when they should be loose then one of them's stuck now if one of them stuck in what you can do real easy is just spray a little Lube down on the base of the stem and just hit it a couple times or move it in and out a couple times until it stops sticking a lot of times that'll free it up push it in you can kind of try to turn the whole stem and everything as you do it and that'll seat the valve in a different spot that'll turn the valve you can get that rust freed up off of that stem a lot of times it's just surface rust that's actually on this stem down at the valve guide that keeps these valves at a stuck position and it just needs cleaned off in order for this valve to move freely again that can cause a push rod to bend and lots of things to happen in here real easily now both your studs are good don't worry about that but you'll want to check your valve spacing while you're in here also if you take the plugs out it's a lot easier to turn this over to get these adjusted and all I'm doing again to get this out you can take that Middle Screw but I'm just pushing in on the valve and letting that drop out bent push rod that is on the top that is aluminum that is the intake that is where that should be on the diagram it does not show it that way it shows it opposite of that not the correct way for it to go and that's a 69982 push rod from Briggs on the top and then it's a 690 981 push rod on the bottom the one on the bottom it used to be I think this is actually the superseded number the 597 785 so that's the new number you've just got to find straight in the circle where The Pusher that comes off of the cam shaft goes we're going to check this to make sure it's tight afterwards and then we'll check this valve spacing also to put this back on kind of the same thing it seems really loose it shouldn't be that loose that's extremely loose you want to line up this Square part to the back when it clamps down and it's got to be in the way that's even with the other side if it spins it's going to be on there exactly the way that the other person put it [Music] on this calls for 100 inbs okay that is tight but this is really loose let's flip it around now you can do these if you'd like at a/4 inch past top dead center otherwise you can just go opposite when one's all the way in the other one will be all the way out the way these cam shafts are set up and this is going to take a looks like a 13 mm and then I believe a t40 in order to set it loosen this all [Music] up now on these it says 4 to 6,000 for the adjustment on both the intake and the exhaust we going to tighten this you tighten your star to make it tighter close the gap these are way way off he getting closer about right there and I'm going to tighten the 13 against the t40 to hold that t40 right in the same spot it was in that is good you want it to fit in there but you don't want it to be too loose or too sloppy if it's too sloppy and you can just throw it right in there you want to undo that and redo it again I'm going to make sure this is just yeah I like to make sure those are plenty tight otherwise they can back off that goes along with the studs it says I think 60 inch PBS for that one and intake valves all the way in adjust the exhaust valve valve spacing if everything here is good and everything's moving in and out you replace your push rods and then you still run into issues you probably got an issue internally with something hanging up on either one of the pushers that actually pushes the push rod uh the tap it um or something else internally as long as all this stays tight I go about right there tighten it up see what that gives us okay nice and tight against there again I'm going to make sure that's plenty tight check it one last time good to go now we're going to put a 690 971 rocker cover gasket on it you can turn these over make sure everything works good and everything's coming out where it should be and the valve spacing same stays the same as it goes around it's hard without those other spark bugs out seems like seems like maybe that bottom one still a little tight see here when they're both open oh yeah it's got It's loose you just always want to check it you never know make sure everything's working properly when you turn it over before you try to start it especially if you're not familiar with what you're doing these 10 mm these are actually 38 as far as the uh head size goes to them see people bring them in all the time trying to use a 10 mm to get them off and they strip them [Music] out you don't want to overtighten that it's got this line here that sits in that gasket you do overtighten it it will split back on we're going [Music] to put this spark plug in fire this thing up see what happens it's the version Briggs and Straton plug that we use that other gold uh Briggs and Straton plug probably would have been fine that's a 694 385 they've just got kind of that smaller almost E3 looking tip to them not the v-shaped one but the the other the other one they sell believe that's what I'm thinking of anyway I'll remove this other plug other plug is removed see what this side does as opposed to just popping from before well the mower is running on just that one cylinder now let's plug this side in see how well it does on both [Music] [Applause] [Music] [Applause] oh well besides all the smoke rolling off of it uh burning off of that side that hasn't been ran in quite a long time I would think everything's working properly hopefully this helps you if your mower is losing power uh doesn't have full power or bogs or dies under a load and you can't figure it out with your normal diagnostic methods thanks for watching like And subscribe oh

Channel: Individualized Repair Inc

Views: 20,933

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Id: jHdsXcEwz0s

Length: 23min 7sec (1387 seconds)

Published: Fri Jan 26 2024