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Engine basics => Four strokes only => Topic started by: FLOYD CARTER on August 14, 2016, 05:18:13 PM
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I was getting bad runs from a Saito 62. Takeoff OK, then gets rich in the air. Gradually leaning out until after 5 min really perking right along.
Using a 6 oz plastic clunk with uniflo (uniflo attached to pickup clunk about 1/4" ahead). Connecting uniflo vent to muffler pressure.
Finally,. removed the muffler pressure for a standard atm uniflo. Problems went away! Steady runs.
Does that mean muffler pressure is not good on a 4-banger?
Floyd
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well FLoyd, what it means is that it isnt good for your airplane and installation, every one is different However not sure how muffler pressure would cause the problem you describe
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Floyd,
I'm certainly no expert. I have many four stroke powered planes now, including the infamous tri plane!
So far, only the os 52 and the magnum 52 (os copy) have been able to run a muffler. Even my os 30fs, which is the same black head series, will not run with the muffler.
So like mark is saying, the real test is the first couple flights.
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Wow! I run every one of my Saitos on muffler pressure. Do not plumb the tank uniflo, run the vent to the top front inside corner.
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Wow! I run every one of my Saitos on muffler pressure. Do not plumb the tank uniflo, run the vent to the top front inside corner.
That is my setup. y1
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I was getting bad runs from a Saito 62. Takeoff OK, then gets rich in the air. Gradually leaning out until after 5 min really perking right along.
Using a 6 oz plastic clunk with uniflo (uniflo attached to pickup clunk about 1/4" ahead). Connecting uniflo vent to muffler pressure.
Finally,. removed the muffler pressure for a standard atm uniflo. Problems went away! Steady runs.
I have found the same thing many times on 2-strokes, too. I don't know why. although the evidence suggests that, just as Howard and Paul found with crankcase pressure, the muffler pressure goes *down* with increasing RPM instead of up, like you would expect.
Brett
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Wow! I run every one of my Saitos on muffler pressure. Do not plumb the tank uniflo, run the vent to the top front inside corner.
I do the exact same thing with my SAITO engines, From size .30 to .62.
Although they run well with or without, I prefer muffler pressure.
and, whether I use a metal or plastic tank, NEVER uniflow. I could never make it work.
Also, I found that the SAITO seem happiest when side mounted.
Bob Z.
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Thanks for the comments. I'm still not clear why my set up runs best without muffler pressure. I think I'll just accept it, and let it go at that.
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I have used the Saito 40, 56, 72, OS 52 and 56 and always used muffler
pressure. As mentioned earlier, don't plumb the tank for uniflow. I have
always used the Tom Farmer method of plumbing for my tanks. That is,
plumb it so that the pressure line makes a U-turn and comes back to the
front of the tank on the inboard side.
Steve