2 Viton Intake Valve Seals Briggs Vanguard V-Twin 691963

Two Viton intake valve seals for Briggs & Stratton Vanguard V-twin engines. Replaces Briggs part number 691963, which superseded the older 805094. Two seals is one complete engine. Briggs fits a valve stem seal to the intake valve only on these V-twins, one per cylinder, so a pair does both sides and there is nothing further to order. These are Viton, which holds its shape and its sealing lip at temperatures that harden an ordinary seal - and hardening is exactly how these fail. The reason only the intake gets a seal is worth knowing. The intake port runs under vacuum, which will pull oil down the valve guide if the seal has hardened, split or been left out. The exhaust port runs under pressure and pushes the other way, so Briggs does not fit one there. If you pull a head and find a seal on one valve and not the other, nothing is missing. Fits the Vanguard OHV V-twin range, roughly 16 through 40 horsepower, in horizontal and vertical shaft, spanning the 294, 305, 350, 380, 543 and 61H model series and their variants. Read the model, type and code off the blower housing and check it against 691963 in your parts book. The symptom that sends people here is oil consumption with no external leak, together with a puff of blue smoke on startup or after the engine has been idling. That is oil that has drawn down past the intake guide and settled on the piston. Replacing a pair of seals is the cheapest repair on the engine and it is often the correct one. Doing the job means getting at the valve springs. With the heads off it is straightforward. With the heads on, an air line into the spark plug hole will hold the valves closed while you compress the springs to release the keepers. Valves, valve springs, keepers, head gaskets and rocker gear are not included.

• TWO SEALS - ONE COMPLETE V-TWIN - Briggs fits a valve seal to the intake valve only on these engines, one per cylinder. Two seals does the whole engine. You are not short a pair and there is nothing else to order.
• VITON, AND WHY ONLY THE INTAKE - The intake runs under vacuum, which draws oil down the valve guide if the seal is hard or split. The exhaust runs under pressure and pushes the other way, so it does not get a seal. Viton holds its shape and its sealing lip at temperatures that harden an ordinary seal, which is what makes these last.
• REPLACES BRIGGS 691963, WHICH SUPERSEDED 805094 - Either number gets you here. Fits the Vanguard OHV V-twin range, roughly 16 through 40 horsepower, horizontal and vertical shaft, across the 294, 305, 350, 380, 543 and 61H model series.
• THE SYMPTOM THAT BRINGS YOU HERE - Oil consumption with no external leak, and a puff of blue smoke on startup or after the engine has idled. That is oil sitting on top of the piston, drawn past a hardened intake guide seal overnight. It is the cheapest fix on the engine and it is very often the right one.
• DO IT WITH THE HEADS OFF, OR WITH AIR - Changing these properly means getting at the valve springs. If you are not pulling the heads, an air line into the plug hole will hold the valves up while you compress the springs. Valves, springs, keepers, head gaskets and rocker gear are not included.