Mark siebenaler 38 #1 Posted July 9, 2023 I have a 3.5 hp brigs on two or three of my very old garden tillers one smokes like crazy at first for awhile then it's fine. I'm thinking it may need a valve job? It is very good for keeping the mosquitos away Share this post Link to post Share on other sites
lynnmor 6,812 #2 Posted July 9, 2023 36 minutes ago, Mark siebenaler said: I have a 3.5 hp brigs on two or three of my very old garden tillers one smokes like crazy at first for awhile then it's fine. I'm thinking it may need a valve job? It is very good for keeping the mosquitos away If the oil is coming from the valves then it is worn valve guides or the oil isn’t returning to the sump. I would start by removing the plate where the valves would be adjusted. 3 Share this post Link to post Share on other sites
Jon Paulsen 282 #3 Posted July 9, 2023 (edited) Beware the valve cover on some B&S engines also functions as the crankcase ventilation, similar to an automotive PCV system. B&S calls this the "Breather." If that's the case for your engine, you should see a hose from the valve cover going to the breather (maybe elsewhere on the intake side). That valve may be sensitive and you will want to be careful with it. I don't have a smaller B&S to look at or get a photo for you. This manual might apply to your engine. Valves are covered under compression, section 6. Section 8 shows the breather and discusses it (B&S page 3, but that's page 4 of the PDF). First check your oil level, because a failed needle valve on the carb can let gas back through the ventilation hose and into the oil. If the oil is increasing and smells like it has gas in it, you have a dirty or worn out needle valve in the carb. They usually run bad too and get oil all over the air filter if the crankcase vents to the air filter box. Run it with a bad needle valve you can get a dead engine, so regardless of likelihood, it's best to check the oil. Run it without the cover on the filter box and you can get a hot oil shower, don't ask how I know If there oil is good, or slightly decreasing, I agree with the above post that the valve guild is a likely candidate. Valve cover/breather on my larger B&S, rectangular cover, L shaped hose is showing going off to the right and up to the air box (hard to see in the photo - squint hard!). It's behind the carb, so the best photo I can get right now: That's the carb bowl on top, breather vlave/valve cover under, behind the carb when looking straight on... phone is pointing up. Edited July 9, 2023 by Jon Paulsen Share this post Link to post Share on other sites
