|03-21-2016, 08:44 AM||#11|
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I am: Gary L
Join Date: Aug 2008
Location: Tecumseh, Ontario
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Re: Choking a 4 stroke.
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Full throttle. You want to richen it to drop a few hundred RPM.
A reliable idle will be self evident, but may still be twitchy or problematic unless beyond the break in. Until then you will find your fuel consumption much more than normal and idle will need to be higher to keep it from loading up and quitting.
On that note, I would recommend running it as if no break in procedure has been done for at least a few tanks.
The tach is a good suggestion since a change of a few hundred RPM may not be readily noticeable and with a 4-stroke you need to wait longer for any mixture changes to show up.
Leaving the cowl off will allow you to access the settings, check throttle movement and ensure everything is running correctly. It will also allow for adequate cooling airflow and show if things change once the cowl is installed.
I ran my first Saito, a 91, bolted to the nose of the Skybolt for approx a dozen flights. Only problem that showed up was with the throttle linkage. First flight with the cowl installed had it overheat, indicating inadequate or stagnated flow. In my case the open portion below the case provided the easiest path so a minimum went by the jug and head. Copying full size practices I installed ducting and blocker plates to retain the flow over the engine. 330+ flights proved it worked.
The point is you want to have easy access and get an idea of how the engine behaves, then change installation. If nothing negative happens you at least confirmed it should still be reliable in flight.
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|04-11-2016, 12:28 PM||#12|
I am: Lindsay D
Join Date: Aug 2014
Location: Edmonton, AB
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Re: Choking a 4 stroke.
On my Saito 1.8 with a pitts muffler I would block the 2 exhaust tubes with my finger and rock the prop back and forth a couple times through compression until I could see fuel drawn up to the carb. Starts easiest using an electric starter when cold but very easy flipping backwards against compression with a stick afterward.
Years ago Saito 4 strokes had chokes on them but were found to be unnecessary.
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