BRAND NEW STIHL FS 111R / ZERO COMPRESSION / YOU WONT BELIEVE WHAT THE PROBLEM WAS!

what's up guys more medic one and today we have got a steel fs-111r on the bench and the customer said that he turned it on its side to do a little edging and the engine just stopped and would not restart and it felt like it wasn't getting fire to him but when i pull the rope through it has zero compression put the compression gauge on it zero i did a leak down test on it it's getting a hundred percent leakage past the intake valve so let's go ahead and take this thing apart but first let me give you a little back story well before you keyboard cowboys start typing well it's under warranty why don't you just bring it back don't work like that where i work if it can be fixed we fix it we can't wait for warranty this unit has to be out in the field cutting grass it's just the way it is now if it was an engine or something like that blew up then yes we would have to send it off for warranty we're not going to be out that many dollars to repair a machine that's under warranty but this is going to be a real easy super easy fix so let's get started the customer claims he's only used this machine five times but get this this machine is being used i'm talking about heavily they are using they have all new trimmers this year and uh they're running these trimmers for 12 hours per day only shutting them off to refuel and restring the heads and it's they're not giving these things a break not one second so what are some things that would cause zero compression and a hundred percent leakage past either your intake or your exhaust valves in my experience is either going to be a stuck valve a little piece of carbon under the valve got stuck or something is messed up in the valve train uh but let's like i said let's just go ahead and pop the covers off and let's see what's going on here missing the screw there let's go ahead and pop the valve cover off now if we take and pull this engine through with the starter rope you can tell that both the valves are opening the compression release seems to be working but check this out if you look the rocker arm is on top of the valve stem do you see the the u-shape of the rocker arm right here this is supposed to be like this and it's supposed to encapsulate the valve stem so i guarantee you whenever i take this screwdriver and push this rocker arm over the valve came up and now i guarantee you we're going to have a gap that's going to be too wide we need to set the valves and let me tell you what i think has happened before i adjust the valves i checked my lash and it was spot on but as you can tell it is mechanically impossible if everything is working correctly and everything's right for this rocker arm to get on top of the valve stem like that it's cradled in between these two ramps on the rocker arm so how in the heck did it jump up there that fuel looks a little bit rich to me on oil the spark plug is definitely running a little bit rich carburetor settings are probably okay it's just that the tank is being ran or the engines being ran put a little bit too much oil in the gasoline and i tell you one thing here's another little piece of information that i was told is that one of the operators was doing a head swap because the head messed up and they didn't have time or what what they do out in the field if they have one that they can't just restring real quick they'll just zip the head off and zip another one back on well the head didn't get tight and it came off while they were using it and when he turned it on its side the rpms whenever the head came off the rpms just shot through the roof because there was absolutely zero load and what i think happened here is that the uh it went past the rev limiter just for a split second and caused the valve to float and what that means is the valve is down whenever the rocker arm pushes the valve down and then the engine is spinning so fast that the rocker arm comes up faster than the valve spring can make the valve come back up and it just it's just a sequence of uh just that's what float is is that the valve can't keep up the valve spring can't keep up with the engine speed the valve goes up and down [Music] freely with no binding or sticking so in my professional opinion i think it was just a combination of gravity forcing the rocker arm that way whenever the trimmer was turned on its side and a little bit of valve float from whenever the head flew off but hey this was kind of a neat one to diagnose and uh hey if this content helped you out give me a thumbs up and smash that subscribe button and while you're there click the bell so you'll get all my new videos well i hope this helps you out and we'll catch you guys on the next one have a great day [Music] [Music]

Channel: THEMOWERMEDIC1

Views: 79,863

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Id: SEP5RbGy1aQ

Length: 8min 8sec (488 seconds)

Published: Wed Jun 09 2021