gazzazh Posted November 22, 2011 Share Posted November 22, 2011 Hi, I have a four stroke OS 120FSII with Pump, that i am using for my funtana 125.. I got a pitts muffler for it.. I have 2 questions.. 1- Do i break in the engine with the Pitts muffler? 2- There is a pressure Line on the Muffler.. DO i seal it .. or do i connect the pressure to the thank.. I know that four stroke engines don't need a pressure line I have attached the photos.. Thanks a million..@import url(http://www.modelflying.co.uk/CuteEditor_Files/Style/SyntaxHighlighter.css);@import url(/CuteEditor_Files/public_forums.css); Quote Link to comment Share on other sites More sharing options...
YakMad Posted November 22, 2011 Share Posted November 22, 2011 Gaz, I would suggest using the OS silencer to break it in as it will rule out any potenial problem that an after market exhaust could create. I know fourstroke are not sensitive to exhaust back pressures but sometimes the pitts type mufflers can create problems when there was none, not saying this will happen to this engine but at least if it's run in on its own exhaust you know the engine is running well before you change mufflers. The engine you have does not need exhaust pressure as it has a pump, just follow the OS instructions on how to plumb the tank. Quote Link to comment Share on other sites More sharing options...
ken anderson. Posted November 22, 2011 Share Posted November 22, 2011 hello gazzazh...i would set it up with the os silencer/exhaust..maybe a tank or two...and then fit it in the model with the new pitts muffler....prob the engine will need a slight retune.....at the end of the day thats the silencer its going to be using...and as stated..blank off the ex/pressure nipple......if your not 100%...put it in a box a send to ne..1 land ASAP..... ken anderson ne..1...end of the day dept.. Quote Link to comment Share on other sites More sharing options...
FlyinBrian Posted November 22, 2011 Share Posted November 22, 2011 It's a pumped engine so does not need exhaust pressure. I would run in on the standard silencer then try it with the pitts type before fitting to the model to get the carb settings somewhere near right. I had one of these engines untill recently. To start I had the main needle about 1 1/2 turns open, Open throttle to full and without the glow starter attached give the engine a 5 second or so burst with the starter then shut throttle to idle, attach glow and start, worked every time! Mine needed a minute or so running from cold to settle itself before flying. Quote Link to comment Share on other sites More sharing options...
gazzazh Posted November 22, 2011 Author Share Posted November 22, 2011 Thanks guys.... Ken.. I think i will keep this one.. Maybe next time Cheers, Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.