Hardy

The engine is new and never been run before. The fuel pump will not pick up fuel until you prime the pump. No air in the pump suction line and it will pump. I can pushed fuel through the pump with a suringe when I remove the hi speed needle. Fuel will also move through system when I open the throttle near full open (into the injector line). The engine does run well once the pump gets primed. I'm new to this type of ys engine. Any Idea's

apereira

Hello,

You still have air on the pump, there is a small bubble inside wich is some times a little tricky to get rid of, the way I do it, open the throttle fully open, and turn the prop back and forth (not a complete turn), moving it CCW after the compresion stroke, right there you will hear a click, that's the pump, move it back and forth around that click, and leave the injector hose disconencted, do that until you think fuel is comming out with no air and the amount of fuel matches the prop movement.

Good luck

Alejandro P.

Hardy

Hi apereira Thank you for the response.
I have since researhed some of Troy Newmans articles on the Dz engines and found them very helpful. I have put a clear fuel line between the pump and the carb which made it easy to see the bubbles moveing in the fuel line. With your method the bubbles move with every stroke of the pump. So do you leave the pump primed (when the engine is in daily use)? Everyone talks about the DZ flooding, this engine with the throttle closed will not accept fuel to the carb. If the throttle is near wide open the carb will accept fuel with very little pressure applied. So when does this flooding take place? Asuming you leave the engine parked with the throttle closed. Thank you for your time.

apereira

I have always left the throttle closed and never flooded the engine yet, of course flooding will occur if it is hot, then the tank will pressurize and will force fuel into the engine, but it has to be sitting like that for a few hours.

So far never had problems on the 160 or 170 by using this method, I used to have shutoff valves but stop using them about two years ago as never really needed them.

Best regards

Alejandro P.

Hardy

Thank you for the reply apereira. Are you using a check valve on your vent line. I put in a long vent line that loops to the back of the tank than excites at the fire wall. I spent some time with the engine today with a much better feeling in the end. Troys starting method seemed to work quite well. Boy one mistake and that engine kicks like a mule. Have two other ys engines that run quite well. Thanks for the info.

apereira

Yes, I always use a check valve on the vent, if you are in a hot enviroment having the loop will prevent the engine flooding for the reasons a mentioned before. On the kick back, make sure you use a delayed glow ignitor and it will never happens again, those kicks can bend a valve, break the engine mount etc, depending of course on the installation and how hard it kicks.

I prime the engine with the method I mentioned about six times, and it wil fire inmediatly as soon as the glow plug lits.

Hope this helps,

Alejandro P.

Hardy

Thank you for the reply apereira. The engine is mounted on a YS supermount. The plane is a mxs-r which I would like to try in IMAC. I have been starting it with a very nearly closed throttle which makes it start with out kicking. I plan on getting a Rcats glow starter with a 5 second delay. The engine was very well oiled up on the orginal starting. It responds very well to hi speed needle and regulator adjustments. Ihave been getting to the point that throttle response is reliable. The fuel is cool power pattern 20% nitro, it will not develop the power of 30% cool power nitro. It is swing a pattern prop 16x12 at 8200 to 8400 and it is still rich. Thanks for your help with this engine.

apereira

You have the best mount in my opinion, that's what I use, but on the prop try the APC 17x12, that is the best prop for the engine, once is fully broken in and running powerfull you can go 17x13 if you use 30%nitro, if the engine is new, is better to have it rich for the first 6 or 8 flights.

Best regards

Alejandro P.