Altawalt

I have 7+ year old YS 53FZ engine that was new in box when I installed it a few months ago (Don't ask. Suffice it to say that it took me a heck of a long time to finish the plane and run the engine.) and I can not get it to run correctly.

Here are the facts:
1. New, but 7 years old, when I pulled it out 6 months or so ago.
2. Using Saito muffler and pipe on engine b/c YS muffler and pipe didn't fit inside installation (Sig Citabria).
3. Have attempted to run it on both stand in in plane with same results.

4. Results:
a. Idles but runs rough and won't stay running without relatively high idle setting.
b. Transition to high end takes 3 to 5 seconds while the engine seems to "spool up".
c. I get lots of bubbles in the fuel to carb line during transition and at high throttle.
d. At high idle the engine doesn't sing but seems to labor but does go to high throttle (not too rich, not too lean, still doesn't "sing").
e. Engine vibrates more that I'm used to. At high throttle, fuel darn near foams.
f. 10oz tank balloons with pressure (I'm assuming this is normal.?

Any thought? Little help? Lotta help? I don't want to abandon this engine, especially since I've moved it around for 7 years and the Citabira is cut for it's fit.

Let me know what to do and I'm in.

Thanks,

Eric

Troy Newman

The idle is likely too rich. The original 53's didn't have the air bleed screw, however some of these engines did, and some were converted by Futaba USA the then importer of YS engines in the North America.

Go to this page for details on setting it up and mixture settings.

http://www.probuild-uk.co.uk/factsheets/ys_engines.php

Likely a lean regulator setting will solve your issues. CW rotation on the regulator screw...maybe 1/8-1/4 turn at a time.

Too Lean will surge up and down at idle or will go lean in the mid range throttle up....and start surging if left at about 4000rpm to run.

Troy Newman
Team YS

Altawalt

I appreciate all the feedback, I have confirmed that I have an original engine, no bleed needle. Can I convert this myself, will it make a difference? Are these engines capable of running well with some modification or should I get rid of it and try another path?

Thanks for your help.

MajorTomski

Quite well once it's dialed in. You are using 20% nitro or better?

Troy Newman

The 53 was being built at the time that YS developed the air bleed screw for fine tuning the idle mixture. Its just an added fine tune thing. you can make it run perfectly without it.

No you can't make the modification yourself. It requires new parts and it was not a warranty thing just an improved version. Where it seems to really be needed is when guys try to run 155 or less nitro. The less nitro you use the more critical the mixture settings become. So take this example.

The high speed and the mid range is perfect, but the idle is a little rich and after a few minutes it will load up and die. Do you adjust the regulator screw lean say 1/8th of a turn. Now the idle is good but the mid rage is a little lean and the HS is perfect still. Since the regulator screw adjusts both the idle mixture and the midrange they are tied together. And sometimes small adjustments to the regulator will make big changes one way or another.

Now add in the air bleed screw The same situation the HS and midrange is perfect but the idle loads up after a couple minutes. Its not really rich but it is a little. Open the air bleed screw maybe 1/4 to 1/2 turn to allow more air to slip through the hole and Viola the idle is a little leaner.

If you are running higher nitro fuel 20% and above this problem rarely happens in that you need a slightly large air bleed. The throttle barrel you have already has a air bleed hole in it...t just doesn't have a screw in the end of it to control how large it is. There were a couple of 120's like the NC that under certain conditions this air bleed hole was not large enough. Mainly going to high elevations. Like Denver at 5000-6000ft. Some folks found they needed to remove the throttle barrel and drill the air bleed hole slightly larger to tune this problem out. This was a very rare case but everybody seems to think that their engine needed it so...there are lots of posts in here about it. The air bleed you have in the throttle barrel is they as a fixed value, it is not adjustable. Its fine. I had one of the original 53's this way and it worked flawlessly. And I was flying it in Denver at the 5000ft elevation.

The biggest thing I can say is put some nitro in it if you have the problem I described. It will solve the problem. If you are already running 20-25-30% nitro you will never see it I promise. A select few 120's needed the modification....So YS started making the engines with this adjustable so people would not be taking their engines apart and drilling on them. That is all.

Troy Newman
Team YS

Altawalt

Troy,

You are teasing me away from getting rid of this engine and starting over, i.e. giving the YS another chance. One reason is that my ST51 with the humongous carb won't fit in the SIG Citabria cowl without some serious cutting (read: ruining) of the cowl.

One thing I faled to mention and would like an opinion on...I have substituted a OS four stroke muffler and OS bent header for the straight header and muffler from YS. The OS simply fit in the cowl better.

Question:

1. I'll test this for myself but does this likely affect the running of the YS?

2. Can I run the YS without a muffler at all, just the header?

To answer an initial question that I keep forgetting to address, I am using 15% fuel. The hobby shop isn't open late enough for me to get some new fuel during the week. I'm going to go for 30% to see what happens.

Thanks in advance.

Eric

MajorTomski

Eric, the 15% will be a good part of your problem. Be prepared for a shock on the 30%! And what size prop are you running? I have two 53's of your vintage and they both love 13-6 or 8s. Also remember the regulator is bacwards screw it out to lean it out.

Troy Newman

Incorrect info there major Tomski


The regulator screw is CW or IN to Lean

Out or CCW to richen.

Works the same as the HS needle.

Troy Newman
Team YS

Altawalt

Troy, any thoughts on the OS muffler or just running a straight pipe?

Thanks,

Eric

Troy Newman

No thoughts either way. The OS muffler should work. I have never tried it but it should work.

Troy

Altawalt

Thanks for your insight gentlemen.

When I get a chance to try all this I'll try to post the results.

Eric

MajorTomski

Sorry looong day yesterday, guess that's why we're supposed to leave the answers on the support threads to the support team
Lesson learned