Small Engine Reassembly 3.5 HP Briggs and Stratton

today we're going to be rebuilding our three and a half horsepower Briggs and Stratton engine as you can see I have all my parts laid out here to make it just a little bit easier to rebuild I also have a nice clean workspace and I have all my tools in oil and assembly grease ready to go the first thing we need to do is we need to put our crankshaft and piston in if you happen to have a piston ring off you can use your ring expander tool to go ahead and slide it on make sure you check the manual to see the order of the Rings and the orientation of the Rings you also want to turn each ring to make sure that the gaps do not align you want to turn them about 30 degrees off from each other next we're going to apply a little assembly grease to the magneto and crank pin Journal's on the crankshaft next we can put the crankshaft inside the crank case and just wipe off any excess grease if there is any also be sure to orient the crank pin journaled down so that we don't hit it when we put the piston in before we put the piston in we want to apply a generous layer of oil all around the piston and of course if you need to make sure you realign your piston rings so that the gaps are about 30 degrees apart from each other once that is ready you can put the piston inside the ring compressor tool and tighten it down as tight as you can to make sure that the Rings are fully compressed make sure your piston is oriented correctly before installing it once the piston is in you can gently tap it with the rubber end of a mallet if you get any resistance at all double-check that your tools compress fully and make sure that the crankshaft isn't being hit with the connecting rod any resistance at all means there's a problem the piston should slide in very smoothly next we could push the piston down and rotate the crankshaft so we can install the connecting rod cap there are grooves on the connecting rod cap and the connecting rod so the cap can only be installed in one way you also want to make sure that your splash finger is on the bottom bolt the splash finger will splash oil inside the crankcase once you get these bolts tightened down snugly you need to use a torque wrench to tighten around the rest of the way be sure to reference your user manual to get the exact torque specifications once this is complete make sure that your piston and crankshaft still move freely and smoothly next we can install the camshaft and the tappets for the tappets i like to turn the engine upside down just so they tap it's don't keep falling out the tap it's going to small little holes right below the valves and a little assembly grease will be good for them now we can install a camshaft if you guys remember from the disassembly video the cam gear and the crankier have small little indicators that need to be aligned perfectly so that the piston and valves are timed perfectly together so I'm gonna insert the crank gear and rotate it so that it's easier to align with the cam gear the camshaft goes at the small hole in the back of the crank case and once you get those two dots aligned the engine is now perfectly timed to hold these things together we can insert our bearing the bearing sticks in the crankcase cover and helps keep everything balanced so we can apply it a little assembly lube and then we're gonna use a metal pipe with a padded end on it you want to make sure that the end of the pipe is padded so you don't damage the bearing we're just going to use a few gentle taps with a rubber mallet and once that bearing is set into place it's gonna hold everything in nice and snug next we can install our crankcase cover and gasket but before we install the gasket I like to apply a little bit of oil all the way around the gasket it just to help it seal the pores on the crankcase cover and the crankcase once we get the gasket on we can apply a little bit more oil to the opposite side you want to install the bolts in a crisscross pattern and once you get them finger tight you can follow up with a torque wrench and torque them down to the exact specifications listed in the manual [Music] once that is complete we can move on to the valves and valve springs I do have a hold of a video that shows how to install these and much more detail so for this video I'm just going to move through it rather quickly you [Music] you can rotate the crankshaft to make sure that both valves open with the valves and valve springs installed now we can install the valve cover again I like to apply just a little bit of oil to the gasket before installing it [Music] next we can install the head gasket the cylinder head and the small metal shroud piece that goes on top make sure that everything is nice and clean before you install it just like the crankcase cover we're going to install these bolts in a crisscross fashion following up with a torque wrench to tighten them down the correct amount next we can install the flywheel starting with the flywheel key the flywheel key is going to sit in the groove that's on the end of the crankshaft once we get the key inserted into that groove but we can carefully install the flywheel making sure that the groove on the flywheel lines up with the groove on the crankshaft and the flywheel key locks them both together when turning the flywheel you should feel some compression at the spark plug hole now we can install the guard and the bolt that holds the flywheel on [Music] [Music] when using the flywheel holder try to avoid the fins right below in the magnet once your flywheel is secure you can use your torque wrench to fully tighten the flywheel bolt [Music] again double check to make sure everything still moves freely [Music] we can install the carburetor and it's gasket this time we do not need to apply oil to the gasket you want to make sure that the gas tank into the carburetor is facing towards the bottom of the engine [Music] next we can install the gas tank and it's gasket again we don't need oil on the gasket this time make sure that you still have your screen on the bottom of the carburetor that goes into the bowl of the gas tank [Music] [Music] [Music] [Music] [Music] now we're going to install the armature that goes right above the flywheel because the governor hooks to the armature these two pieces need to be installed together [Music] [Music] before the bolts on the armature are fully tightened we need to use a feeler gauge to make sure that the armature and the magnet on the flywheel are properly gapped [Music] [Music] once the feeler gauge is in place you can fully tighten down the bolts on the armature be sure to rotate the flywheel to make sure that the armature does not hit the flywheel in any place now we can install the springs and linkages to connect to the governor the carburetor and the throttle to install this linkage and when I actually need to remove the plastic part of the governor to do that I'm going to use my needle nose pliers and carefully bend the tab holding the plastic piece on with the plastic part of the governor free I can hook my linkage to the bottom hole on the governor and then I can hook it to the correct spot on the carburetor with this linkage on I can put the plastic part of the governor back and make sure that everything moves freely the spring connected to that linkage is going to hook right here to the throttle control before we install the throttle assembly we need to make sure we hook up the choke linkage this linkage is going to connect to the choke control and the throttle assembly to the choke on the carburetor [Music] [Music] once that's done we can finish installing the throttle assembly two screws attach it to the gas tank now we have one more spring to install the connects to two different spots on the carburetor one is a fixed point and the other is the throttle once you're done make sure that all your springs and linkages move freely and operate correctly also don't forget to bend the tab back on the governor a very important aspect of this engine built is the kill switch the kill switch is going to connect to the tab on the back of the armature but then it's going to be ran through a little hole on the governor it's going to end by being connected to a small tab right below the throttle once the throttle hits this tab it stops the spark to the engine now we can install the breather tube that connects from the valve cover to the carburetor we can also go ahead and install the exhaust next we need to install the air cleaner assembly that goes on top of the carburetor when doing this you want to make sure you close your choke that way if you drop any screws like I usually do they won't go inside the carburetor [Music] when installing the cover make sure that the vent is faced away from the exhaust that way it's pointing in clean air now we can go ahead and install the shroud [Music] [Music] [Music] [Music] [Music] the last thing we need to do is install the spark plug when you're doing this make sure you don't over tighten the spark plug you can use a socket wrench but make sure that you're only tighten it to where it's snug once you have the spark plug installed you can connect the spark plug cable now we can go ahead and fill the gas tank and the oil first to put oil in the engine I'm going to use a screwdriver to get the oil cap off then I can use a funnel to put the new oil in I only need to fill the oil up to the bottom of the threads where the oil cap goes too much or too little oil can be bad for the engine [Music] once I'm done I'm going to reinstall the oil cap and then make sure it's nice and tight again using a screwdriver [Music] [Music] now we can put a little bit of gas in the gas tank and make sure our engine runs [Music] here the engine is set up in the exhaust hood I have the exhaust hooked up and I have the engine bolted down to the rack now we can start the engine [Applause] you [Music]

Channel: Shawn Davis

Views: 190,229

Keywords: small engine, reassembly

Id: PJgDUHcpQrU

Length: 22min 46sec (1366 seconds)

Published: Wed May 06 2020