heli-dan

My Feedback: (12)

Man I don't what to think...I'm pretty good setting up 4 strokes, but this thing has kicked my butt. I purchased the motor used, placed it on my engine stand set the low and high end. The motor sounds good and the low to high transition was great. With the throttle approx 1/4 stick I invert the motor the rpm starts climbing approx 2000 rpm and when i flip it back over the rpm lowers. If I try this at a idle the motor quits when inverted.

I thought the motor was lean so I adjusted the regulator richer, but I can't seem to get the regulator to rich. I've replaced the regulator and diaphram and still no luck. I've followed alot of the on-line help topics regarding this problem. It's defiantly a fuel delivery problem I just figure out the combination.

I was going to send it to YS Parts and Service, but they said, they only tune the motor straight up. Anyone have any ideas?

tadawson

Stupid question, but you have confimed that you have pressure in the tank, and that the check valve is present and installed in the correct direction? (Forgive me asking this, but from your post, I can't tell if this is your first YS or not . . .).

- Tim

Hughes500E

My Feedback: (16)

How did you plumb the tank?
2 Tees with 2 fuel dots or three lines and two dots etc etc?

heli-dan

My Feedback: (12)

Tim,

Yes, this is my first YS motor...I have alot of pressure in the tank after running the motor and the check valve is working correctly, only allowing pressure to go in one direction.

heli-dan

My Feedback: (12)

Huges500,

I went with three lines and two dots. Is this wrong?

heli-dan

My Feedback: (12)

Is it possible to mount the regulator on the motor backwards?

asmund

My guess is that you need to adjust your low end setting and not the regulator since the problems occur at 1/4 stick to idle. The low end setting on a YS is opposite of what you are used to on other fourstrokes. When turning the screw in (clockwise) you actually richen up the low end and when turning the screw out you lean the low end. This is because it is an airbleed carb and only YS and a few other makers use them.

heli-dan

My Feedback: (12)

aumund,

Thanks...I will give that a try. I thought the low end only is acitve when the throttle is below 2200 rpm and then the high setting comes into place.

togatoga

My Feedback: (42)

If you can't richen the mixture by adjusting the regulator and the engine runs differently in upright or inverted mode, then there's a leak or clog somewhere. Used engines do occasionally have problems especially used YS engines
I would take a look at the carb for any obstructions or air leak then have a close look at the regulator.With the screw turned way out the engine should pour out fuel from the fuel line.In fact,it should be very easy to let the engine run extremely rich by adjusting the regulator.The gaskets and O rings act up as the engine ages and can be a problem.

nonstoprc

My Feedback: (90)

The glow plug can also play a role here. Is the OS-F and good?

RPM jumping up inverted could imply the fuel flow becomes restricted in that position. It might be a good idea to double check fuel tank, tubings and filters.

YS engines will not run well if there are any air leaks. But that probably has nothing to do with engine position.

togatoga

My Feedback: (42)

Sometimes oil blocks off the air leak which results in this anomaly. Seen that happen in one of my engines.A change of gaskets solved the problem. However, I must add that I changed the gaskets not because I identified the problem but did it out of frustration!

heli-dan

My Feedback: (12)

togatoga,

man that's funny...I just got done changing all gaskets and rubber "o" rings. The motor is getting rich using the regulator with the smallest amount of adjustment and stay running when I invert it. Now I have to work on the tuning it correctly.

Thanks guys for your help...