4 stroke
12-06-2006, 09:51 PM
#27
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RE: 4 stroke
here is a question for you 4stroke fans I have 2 OS 91 surpass engines, a surpass II, and a OS max 91sp.
the surpass II has a recirc line from the case to the intake manifold, the 91max just has a nipple on the bottom of the case. I really don't want oil in the cowl and a line flapping around the cowl doesn't seem to solve the problem, I have been told that pointing the hose down will help draw the oil and fuel out and helps keep the berings lubed up. what does everybody do with there vent lines
the surpass II has a recirc line from the case to the intake manifold, the 91max just has a nipple on the bottom of the case. I really don't want oil in the cowl and a line flapping around the cowl doesn't seem to solve the problem, I have been told that pointing the hose down will help draw the oil and fuel out and helps keep the berings lubed up. what does everybody do with there vent lines
12-07-2006, 08:02 AM
#28
RE: 4 stroke
Bigtim--The newer OS four stokers have the recirculation line while the older ones simply have a nipple. I just run a piece of fuel line from the nipple out a hole in the cowl, if the plane has a cowl, or let 'er hang if not. A little oil comes out but not much. Bonus is squirting a little oil into the line when done running engine for storage. Just be careful in the car because if you turn prop it will squirt out if it has not been spun into depths of the engine. Hope this helps.
12-07-2006, 11:06 AM
#29
RE: 4 stroke
Greg is right on the money.
The new 91 surpass' have that line return to the intake manafold (Note: this type MUST use a pressure line from the muffler to tank)
The previous versions (With the nipple on bottom) do not NEED to use muffler pressure, and as others have mentioned, you can just put a piece of fuel line on the nipple and run it outside the cowl... or you can do nothing with it if you don't mind getting some black oily stuff on the inside of your cowl.
The new 91 surpass' have that line return to the intake manafold (Note: this type MUST use a pressure line from the muffler to tank)
The previous versions (With the nipple on bottom) do not NEED to use muffler pressure, and as others have mentioned, you can just put a piece of fuel line on the nipple and run it outside the cowl... or you can do nothing with it if you don't mind getting some black oily stuff on the inside of your cowl.
12-07-2006, 10:24 PM
#31
RE: 4 stroke
Bigtim,
Here's what I did on a Super Chipmunk with a Saito 100 that I just finished. I ran the vent tube back down the fuselage to where the cowl joined. There is a small gap there and I let the vent tube end there so that it vents outside of the cowl. I used some tube clamps to hold it in place.
Hope this helps
Ken
Here's what I did on a Super Chipmunk with a Saito 100 that I just finished. I ran the vent tube back down the fuselage to where the cowl joined. There is a small gap there and I let the vent tube end there so that it vents outside of the cowl. I used some tube clamps to hold it in place.
Hope this helps
Ken
12-07-2006, 11:14 PM
#32
My Feedback: (13)
RE: 4 stroke
thanks ken, thats exactly what I was looking for, a pic is worth a 1,000 words of course , the clamps make for a tight little set up .
the newer version has the looping hose into the manifold which makes for a clean engine, but I got a decent price for the engine and I needed another for my Spitfire thanks again BT
my 91surpassII in my H-9 P-40
the newer version has the looping hose into the manifold which makes for a clean engine, but I got a decent price for the engine and I needed another for my Spitfire thanks again BT
my 91surpassII in my H-9 P-40
12-27-2006, 01:54 AM
#38
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RE: 4 stroke
OK,
you are right. Four strokes will never work inverted becasue of that stupid, poorly engineered intake pipe.
Too bad I just maidened yet another P 51 today with a magnum 70 FOUR STROKE mounted INVERTED, and had not one problem at all. of course, I did have some problems at first until I got it all worked out by TUNING the engine PROPERLY. THe engine had previously been mounted 90 degrees on a cub. Mounting it inverted, on a different plane with a different fuel delivery setup created the need to actually TUNE the engine. Once this was done (about a two to three minute job) it never died--during four flights today. Simply Amazing.
Of course, I followed that by flying my Top Flight Gold Texan that I built and currently fly with an evolution 100 two stroke--also mounted inverted-and it too flew like a champ. Of course, I utilize a header tank on it to properly align the fuel storage with the carb. Never had one ounce of problems out of it either (please, let's don't start an argument about using header tanks to adjust fuel delivery aspects on this thread).
It's amazing what can happen when your plane is set up PROPERLY--two or four stroke, it really doesn't matter.
But, you are correct. Whatever works for you is what you should stick with.
Send me all of your worthless four strokes, please.
you are right. Four strokes will never work inverted becasue of that stupid, poorly engineered intake pipe.
Too bad I just maidened yet another P 51 today with a magnum 70 FOUR STROKE mounted INVERTED, and had not one problem at all. of course, I did have some problems at first until I got it all worked out by TUNING the engine PROPERLY. THe engine had previously been mounted 90 degrees on a cub. Mounting it inverted, on a different plane with a different fuel delivery setup created the need to actually TUNE the engine. Once this was done (about a two to three minute job) it never died--during four flights today. Simply Amazing.
Of course, I followed that by flying my Top Flight Gold Texan that I built and currently fly with an evolution 100 two stroke--also mounted inverted-and it too flew like a champ. Of course, I utilize a header tank on it to properly align the fuel storage with the carb. Never had one ounce of problems out of it either (please, let's don't start an argument about using header tanks to adjust fuel delivery aspects on this thread).
It's amazing what can happen when your plane is set up PROPERLY--two or four stroke, it really doesn't matter.
But, you are correct. Whatever works for you is what you should stick with.
Send me all of your worthless four strokes, please.
06-08-2007, 01:06 AM
#39
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RE: 4 stroke
I ran an OS 70 upside down with no problems... started and ran great... it did die inverted once but, that means it was upright..?? I just finished building an Edge540t.. put in an OS .91fx - 3/4 inverted.. Im counting on that motor to purr... Ill find out this weekend.. 
