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Old Mar 25, 2010, 11:51 AM
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Keleo exhaust on saito 170R3 problems.


I have a Saito 170R3 with a Keleo collector ring fitted.
I have some issues with the engine peaking after first starting her up.
I have to surge the engine from high to low idle quickly then eventually she'll clear and I will have full peak r.p.m's.
At first I thought it might be the lower cylinders fouling with excess fuel But now I'm thinking that maybe the collector ring is restricting the flow of the exhaust gases to one or two of the cylinders.
It nearly cost me my GeeBee a week or so ago after it bogged down after a long period at idle then powered on again to climb out.
I am going to try the straight pipes that came with the engine to see if this improves it , & will post my results But in the mean time has anyone else had these issues with radials, or was my first thought ( fuel ) the issues others have found.
Going to be away for a week so wont be able to test my theory till then.
Thanks Steffan.
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Old Mar 25, 2010, 12:47 PM
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I doubt that the exhaust ring is causing the problem, but your approach should yield some answers.
Old Mar 26, 2010, 08:24 AM
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I'm with Jim, my money is on the low speed needle being set too rich, it controlls about 85% of the throttle range mixture. If it is too lean the engine would quit when accelerating but loading up on deceleration is a sure sign of too rich.
Old Mar 26, 2010, 09:12 AM
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One other thought:
How new is this engine; i,e, has it run much?
My Saito 90 twin had the carb low speed set REALLY rich as suggested by I TOBOR above. I figure Saito does this to help with the break-in procedure.
In a pinch, you could always bolt it up to a test stand and remove the exhaust entirely until you get it tuned to the approximate needle settings needed to get it running properly.
Old Mar 26, 2010, 10:34 AM
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Thanks guys ,as I said my first thought was fuel but hadn't considered the low speed needle setting I will remove the cowl first & play with the low speed needle setting first before I do anything else.
The engine was run in per instruction manual on a stand & has had about a dozen flights or more, & the high idle & engine performance has increased in that time ,but so has the bogging down issue after a period of time at idle or straight after start up,so having that setting factory set rich for run in sounds more feasible than my other ideas.
Will report back with results.
Thanks fella's.
Old Apr 07, 2010, 09:12 AM
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Fired up the 170 today leaned off the low speed needle ( only required 1/4 of a turn ) and problem solved.Also using some new fuel , she now transitions from a very low idle to full noise smoothly with no bogging down even after sitting at idle for a good couple of minutes.
Thanks for the help guys ,dont no how I missed that one but thats whats great about these forums.
Cheers Steffan.
Old Apr 08, 2010, 10:24 PM
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Well I guess the proof would be in how she flew, & WOW!! I am a very happy man at the moment.
I was begining to think seriously about buying a gasser for the GeeBee ,anyway took her to the strip for the first time since leaning out the low end needle & she was pulling 8700RPM with a 16x8 Menz PropS.
Once again was transitioning perfectly & sounding wicked !.
1st take off she accelerated smoothly till about 3/4 throttle then got the pull to the left ,lifted off nicely ,climb out was a nice & scale like , then leveled off & WOW she just turned from the nice mild mannered lady I use to know into a very quick & agile Minx.
My mate & I couldn't believe the difference ,I am using better fuel , but that would not have made this much of a difference on it's own, I could manage a loop from level flight most times before ,but had her fall out on a few,
Now I can Loop from a climb ,but also can do the hugest loops ( seem to take up the whole sky ) which look awesome.
The other benefit of course is I now no longer have to fly at full throttle for most of the flight so the flight times have gone up (still had half a tank after the second flight ).
Had to share my excitement, I love this engine it sounds so right for a model like the GeeBee Z & now I'm getting the performance to boot.
Thanks all for your help.
Steff
Old Apr 09, 2010, 09:08 AM
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I'm happy things worked out for you with your new radial. Any hobby is something that we do to make ourselves feel better, proud, happy etc. If putting an expensive scale looking engine on your creation is what it takes, I say go for it. I have two twins and a four and wouldn't change them for the world!

And NOTHING can compare with the sound of a radial.


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