Dang strange starting issue.

[JimLerch]

YS 80 ST in a Rapto 60, third day in a row its done this.

When starting it the first time for the day, its like I have the mother of all oil slugs in the motor. I crank and crank and crank. Remove glow plug igniter, crank some more at various throttle positions. Put Glow igniter back on, crank it some more and finally, it will catch after maybe 2-3 minutes of continual cranking.

Once its started, it initially idles like its kinda lean, then settles down and idles / runs perfect.

Even more infuriating is it will crank right up and run again as normal the rest of the day.

I've changed plugs (OS-8)
Checked the head bolts.
Checked the check valve

At fist I wanted to say it was because the tank wasn't up to pressure, but that doesn't make sense after a refuel. Then I was thinking that maybe my glow igniter is weak. But the built in amp meter shows normal, and it glow a removed glow plug no issues..

Any thought on what makes a motor a ***** to start after sitting for 20+ hours, but run fine the rest of the day??

Grrrr.......

[archiebald]

YS 80 ST in a Rapto 60, third day in a row its done this.

When starting it the first time for the day, its like I have the mother of all oil slugs in the motor. I crank and crank and crank. Remove glow plug igniter, crank some more at various throttle positions. Put Glow igniter back on, crank it some more and finally, it will catch after maybe 2-3 minutes of continual cranking.

Once its started, it initially idles like its kinda lean, then settles down and idles / runs perfect.

Even more infuriating is it will crank right up and run again as normal the rest of the day.

I've changed plugs (OS-8)
Checked the head bolts.
Checked the check valve

At fist I wanted to say it was because the tank wasn't up to pressure, but that doesn't make sense after a refuel. Then I was thinking that maybe my glow igniter is weak. But the built in amp meter shows normal, and it glow a removed glow plug no issues..

Any thought on what makes a motor a ***** to start after sitting for 20+ hours, but run fine the rest of the day??

Grrrr.......

Slightly different engine, but my YS50ST does not like starting well first flight of the day - but only if......

a) Fuel tank is not sufficiently pressurized. - I give it at least 15 seconds cranking on high throttle.
b) Main needle left normal - Recommended by YS that the main needle can be increased by 1/2 turn for initial start, then put back to normal once running.
c) Using a glow booster - I have a booster and a power panel outlet that are in theory the same voltage. But the power panel supply always starts the engine more easily. I assume the voltage is a little higher.
d) Fuel clip left open - Even though the YS is using a regulator, I prefer to leave my fuel clip on while pressurizing the tank - just in case any fuel is getting through - then open it just before trying to start the engine. Seems to give me more consistent starts.

I didn't understand what you meant by.... "At fist I wanted to say it was because the tank wasn't up to pressure, but that doesn't make sense after a refuel."

Are you saying that you think pressurizing the tank is no necessary in this case? I always crank for 15 seconds to pressurize the tank if it has been open.

[JimLerch]

I didn't understand what you meant by.... "At fist I wanted to say it was because the tank wasn't up to pressure, but that doesn't make sense after a refuel."

Are you saying that you think pressurizing the tank is no necessary in this case? I always crank for 15 seconds to pressurize the tank if it has been open.


Well, fist <> First which it should have, but grammer aside, what I meant was.

Once engine has had a tank ran thru it (or just ran for a few minutes). I can open the vent line, depressurize the tank, close the vent line, and it will start right up and idle with out issue.

So, I was attempting to apply this to the first of the day hard start, but it didn't make any sense. Once fired up for the day, no pressure in tank still yields easy start. If it was a tank pressure procedural error, it should always be hard to start.

I also thought maybe my shutdown from the day before procedure was lacking. Mainly I land, shut down engine, walk back to table, pinch off fuel line to carb, vent tank, but toys away :)

Yesterday I did the "Run it till its 'dry' trick (something I don't like, because running it out of fuel also runs it out of oil... But I tried this,and today it ws just as hard to start as any other day.

Its almost like the methanol in the crank case has evaporated over-night, and its taking time to re-prime that crank case to get fuel up to the combustion chamber..

I don't know, its just very weird..

[CoronaL]

when did it start to do this. If I remember correctly you recently had to partially rebuild your motor as the piston and liner were buggered.

Did it start right after that? Or later?

I would try the "slightly" richer at first start trick and see if that works.

Also, could your fuel have gotten some water in it? How well sealed is your fuel in your bottle assuming your pump etc.. is left attached like mine is all the time. Mine is very well sealed with the slimline cap, and I hear a "woosh" when I take out the fill line from the cap as the tank depressurizes(the gallon tank not the chopper).

ruling out glow, you're left with a fuel delivery issue of some sort.

[Jim Platt]

I have a YS 61 and it did the same thing to me as yours did to you. The cure for mine was to open the idle screw a quarter to one third turn richer and lean the hover needle about two clicks. I cold start by opening the throttle fully and cranking about ten or twelve seconds with the regulator to carb line clamped and, of course, no glow starter. After cranking, close throttle to idle,connect glow starter and open the reg to carb line clamp and immediately hit the starter. Mine usually lights off with just a blip of the starter.
Jim