YS 80 will not start...

[Deano]

I have a YS 80 in a Fury and cannot get the thing started. It has a mechanical pump. I have replaced all fuel lines, taken the engine out and apart to check and clean, replaced clunk lines. I have changed glow plugs and used 2 seperate sticks to light them. It does not seem to want to fire. When I turn it over for awhile, smoke will come out the exhaust but will not start. Any ideas???

[WayneBrown]

sounds like a slug of oil in the regulator or lines.
Hook your fuel pump directly to the inlet side of the pump, and crank backwards.
Reconnect to the tank, and hit with the starter.
Look for fuel to fill the line between pump and carb, add glow ignitor.
If that fails to start it, check your one-way for debris keeping it hung open.

[DavidH]

The motor should start without the one way even in the pressure line. I know it will idle without the one way check valve. I have done that numerous times when I flew YS.

Sounds like you may need to take the regulator off the engine and clean it. The regulator is the black plastic piece on the bottom of the crankcase. IT is not a pump, it just regulates fuel flow to the carb. Sounds like the plunger in it may be stuck.

David

[Deano]

I took off the regulator and checked it and cleaned it. It looked fine. I blew air thru all ports and did not find any obstructions. One thing I did notice was that when I sprayed a lube into the engine exhaust while it was out that I got bubbles as I turned the piston. Like maybe the ring did not have good seal. Before I took it apart it I did get it to idle at half stick, then when it got light on the skids it went way lean and died. Needle settings are correct. Could the ring cause this? No noticable cracks in the case.

[WayneBrown]

sprayed a lube???
What did you use?
some blowby is normal until the engine gets to operating temps.

[DavidH]

What did the diaphram look like. Any pin hole in it and it will not work properly.

David

[WayneBrown]

I gotta wonder if the lube was pertroleum based, if so the diagphram is toast.

[Tim Tompkins]

It will go very lean if the check valve is not pressureizing the tank. To check it is simple, after it runs for a min. pull off the line and listen for the air hissing out of the tank. You need good sealed lines to keep the tank pressure up. What you are describing is what has happened to most of us when we leave the pressure line off. Just like you said, starts and when about to lift it quits. TimT

[Deano]

I used WD 40. The diagphram had no pin holes in it at all. Tim, I will look at the check valve again. The problem is starting the thing in the first place to build the pressure. I know there where some issues with the YS 80 and cracked crankcases but I really don't see anything like that. I'll keep looking.....

[Deano]

I'm thinking about shelving this 80 and putting into it a OS 90 SZ. My current gearing is 8.45 to 1. What gearing should I change to if any and will the engine mount fit the OS on the Fury ???

[DavidH]

The problem is starting the thing in the first place to build the pressure.

YS's do not need pressure to start. They don't even need pressure to run. They do need pressure to run correctly after they are running.
I have on more than one occasion forgot to hook the line back on the checkvalve. Started the motor and got the model into a hover. Only did I realize the pressure line was disconnected when the motor started to go lean. But it will run with the pressure line disconnected.

David

[WayneBrown]

I used WD 40.

.
Thats BAD.. you cannot use a petroleum based lube on silicone.
Sounds like you have some crap in there somewhere yet.