!!!91 AC
 

Troy, HELP !!!! I get my 91 to start on first flip. I bring the rpm's uo to about 5000, and the motor just looses power and slowly dies. Have new YS plug, running 20/20 YS fuel, 15/6 prop. Started with 1 1/2 out for the low and high, reg, flush with case. Why does it die like this? Thanks, Guy

RE: !!!91 AC
 

Not sure....

What happens if the HS needle is open to 2 turns...1.5turns might be too lean?

Also how does it die....does it get violent and detonate and hammer, or does it just spool down and quit?


Could be a sticking check valve that is not allowing pressure to flow into the tank...Is the tank up to pressure when it quits? Ys engines don't draw fuel. They are force fed fuel by the pressure system. At idle the fuel needs are very low and the engine can get enough without pressure in the tank. However above 1/2 power the demand for fuel is so much greater that is the tank is not at the proper pressure it will now deliver enough fuel to the engine. The regulator is just the door man. It opens and allows fuel to flow, then closes off when the pressures change inside the engine and it doesn't need any more fuel for that cycle.

If you are not getting enough flow its common to not have a tank up to pressure, or the tank or lines could have a leak. Also the check valve could be gummed up with oil , and is not allowing the pressure back into the tank.

If the engine spools up to full power then as soon as it starts to get hot it starts to act lean and yet is smoking like crazy then you likely have a severely scratched piston, ring, liner problem.

You just didn't give enough information to answer the question.


Troy Newman
Team YS
Troy Newman