HELP! I recently pulled the above mentioned powerplant from my archives after about a 14 yr retirement from flying. Im trying to get back into it, pulled the motor apart, replaced the diaphragm and plunger, re-assembled it, and for the life of me cant get it to run anything over a high idle. I cleaned all of the small passages in the motor, I dont see anything blocked. I started with the plunger adjustment dead flush with the casing. The tank is pressurized, priming is succesfull, running an OS #8 plug, with hatori pipe (not sure the exact pipe) but it has probably 50 hours or so on it when it was running. Most of my problem is im trying to hand start the motor, but have gotten it to run for very brief periods of time. When it does fire, idle seems overly rich (smoke) then dies after 5-10 seconds. ANY suggestions would be great.

-Andy

Andyt,
Might sound silly, but you may have the vent line and pick-up from your tank crossed. Try swiching fuel lines. I have done that several times and it acted just like you discribed.
Frank

I thought I might be retarded, (still may be) but I did switch them a few times back and forth. Im using the forward most connection for pickup, the rear for pressure. Looking at its design and what-not, this seems correct. I also cant seem to get fuel to move from the pickup unless I have it connected this way. I wish I had the original documentation on this thing... UHG!

-Andy

Here's the owner's manual. There is a fuel hook up diagram there.

http://www.yspartsandservice.com/pdf/61ST2.pdf

is the 61st2 the same as the 61r? there isnt an external fuel line to the carb from the case on the 61r. thanks for the info, anything helps at this point.

-Andy

The ST-2 is a heli engine. It has a different bore-stroke I understand.

The biggest value of this file is the fuel tank hook up?

The st-2 seems to pull crank pressure from the rear cover, the older 61r looks as though it uses the back side of the diaphragm as the pressure... also the fuel line running from pump directly to the carb is different... on the 61r the fuel runs directly through holes in the crank case... if anyone has copies of an owners manual for the 61r it would be a godsend... but as far as I can see, all is well. Is it possible a rear cover, or head leak would cause this kind of running? I would be able to check for leaks but cant get it to run long enough to warm up and give me any sign of leaks.

-Andy

I'd suggest a set of new bearings (Front and Rear)...

While you have the engine down for bearings...Get yourself new gasket and O-Ring set's too...You'll wanna R&R the needle socket o-rings for sure...

Also while she's torn down...Take some compressed air and blow out all those passages in the case, regulator body, needle socket and throttle barrel...

I'm sure you used new gaskets when you re-assembled the engine after replacing the diaphragm...You kinda have to watch the regulator gasket...I have found that sometimes the gasket can partially block one of those passages if your not careful...I almost always wind up enlarging that hole in the regulator gasket a little...

Here is a plumbing diagram for the YS 45 but the 61LS is plumbed the same...I have a PDF copy of the 61LS manual if you wanna PM me your e-mail address I can forward that to you if you like...

The first thing folks go for is the Regulator Adjustment Screw....You gotta learn to just leave it alone...Set it flush and leave it there until you have the engine up and running reliably with the pipe tuned...

I know they can be a pain when they are running like that...I have one torn down that was acting exactly like yours...Waiting on bearings and parts as we speak...

But when they are running right..They are Awesome!!

Good Luck getting her going...

Chuck

It will be tomorrow as I'm not on my computer...But I can help you out there...


Yes...And Bearings...Which after sitting for 14 years need to be replaced anyhow...I know..I know...They feel fine....Replace them anyway...



Have Fun...

Chuck

you guys are great! I actually just got it fired up, finally got it up on the pipe and idling... i think it just needed to breathe a bit... *shrug* but it seems to run pretty well... I in fact did not replace any gaskets, but did check to make sure that nothing was near any holes... it seems to be the biggest problem.... keep the info coming, but I think its gonna be airbound within a couple months! I do plan on replacing the bearings, though I wanted to make sure it ran before I spent a boatload of money on it...

-Andy

the actual owners manual would be great... thank you!

Hey...Glad you got her running!!

If you are an eBay'er...You can find bearings pretty cheep...Under $10 I think...

I know there are tons of bearing folks out there...I'm getting mine from Boca Bearing...

Oh yeah...That engine will be worth putting a few bucks in...

So what are you putting the engine on??

Chuck

it was in a Sig kougar, probably one of my favorite and most reliable kits... it was in the second one I built. first one I started with a webra .40, then a super tigre .51. That one had a slight malfunction (airborne battery came unplugged) my bad. I was 13. The second one I built I put the YS in. it was a ton of fun, reliable, and sturdy... I put hundreds of hours on the two planes. So I found a third kougar that I had when I was a teenager brand new in the box, so Im gonna put that one together... since its rear engine Im planning on running the pipe (since its rear exhaust) through the fuselage. Any suggestions on heat insulation for the electronics? Thanks again guys

-Andy

I have a copy of the 61 FR manual. It's too large to post here..........I know there's an 61 AR manual on the web somewhere. Was there just a plain 61 R? I know I'm looking for a 61 S heli manual. It is the ST-1 version nobody seems to have............