rc4j

My Feedback: (103)

Hi,
I've recently purchased a used .53 that looks to be in very good shape, although I can't get it to run. I don't see any sign of fuel in the line from the regulator to the carb. It has very good compression, valves are adjusted well, and I have the plumbing set up correctly. I get good pressure in the tank, I can pull the line to the regulator (exhaust side) and it will squirt fuel. It seems to hold pressure well also. I just don't get any fuel out of the regulator going to the carb. If I pull the line and squirt some fuel in the carb, and replace the line, it will start and run for a bit, then quit, after burning what was inside the carb. Still no fuel in line to carb. I have removed the regulator and cleaned all ports with raw fuel, verified that there isn't any leaks, that I can see; no fuel leaking or bubbles anywhere. The diaphragm seems ok, although I don't know if it should be flat, since mine seems a little more bubble shaped, but isn't punctured. I've tried adjusting the regulator out, to relax pressure on the spring; and adjusted in as well, still no joy. Original setting at flush, nothing. I tried a syringe on the output line of the regulator to see if I could get it to pull fuel out, still nothing. I've unscrewed the needle valve, and verified it isn't clogged. I'm not sure what's next, but it seems to me, the regulator is the problem. Again, not too sure of how the diaphragm should look. I haven't taken anything apart with the carb yet. Any suggestions?

Troy Newman

The diaphragm is likely deformed if its bubble shapped...This could be your problem....

Before rebuilding it.....

Open the throttle to full

No glow attached

open the HS needle to about 4-5 turns open remember the original setting should be around 1.5-2 turns open.

Then with some pressure in the tank spin the engine while at full power and no glow for about 40-60secs. This should unclog any gelled up oil or junk in the needle valve seat.


You could also just remove the line from the regulator to the carb at the regulator. Then remove the HS needle completely from the engine. Use you syringe to squirt fuel through the needle valve seat. This will flush it. Put it all back together and it should get fuel.

If it doesn't then its the diaphragm or the plunger that could be stuck. remove the regulator and make sure the plunger moves up and down easy...the spring on the back side should push it closed after you depress it...justa couple press and release cycles could clear out any oil that stuck the plunger closed...Raw fuel here can help too.

OH one more thing. You had the regulator off.....The regulator body has a casting protrusion "nipple" or bump on it. This has to point toward the prop. If the regulator body is backward then it will not align the ports internally. So check this also. Its really easy to miss the bump....but when you know its there on purpose then you understand the reason for it.

If none of this works then it needs to have a new silicone diaphragm. That one is probably deformed and not working properly. Sometimes they can actually get really soft and look like a thimble. Usually this is a result of a petroleum based after run oil..


Let use know. Happy New Year

Troy Newman
Team YS

windstar

My Feedback: (9)

Hello Jai,

My name is Robert White. Recently I purchased a YS FZ53 from you for $135 dollars. I have been trying to get it to run, but have been unsuccessfull. The problem I have is the same one you talk about in forum, no fuel getting to the carburetor. I have cleaned the engine orifices out completely, checked the alignment of the regulator (bump facing prop per Troy Newman), replaced the diaphragm all to no avail. Did you ever get it fixed and running before you sold it too me? I will look forward to hearing from you.

Robert White

windstar

My Feedback: (9)

Hello Troy,

My name is Robert White. Recently I purchased a YS FZ53 engine from Jai Williams and have had the same trouble getting it to run, no fuel being pumped to the carb from the regulator. I cleaned out all the origifes in the engine, carb and put in a new diaphragm. No effect. The lifter clearance is 0.003", in spec. Any ideas. When I charge the carb directly, it starts very quickly and runs normally until that fuel is gone. I am checking with Jai to see if it is the same engine.

Thank you,
Robert White

Troy Newman

I will say do the things I posted in December regarding this engine.

The engine does not pump fuel at all. The regualtor regulates fuel that is already under pressure in the tank. I suspect the check valve may not be holding pressure in the tank....Is it holding pressure? Does pressure build in the short runs you are getting. If not then the plumbing or check valve are not installed properly.


Try removing the HS needle and go to full throttle Spin the motor over with a starter and fuel should pour from the HS needle seat.


One other note is the regualtor body could have been installed backwards. There is a molded protrusion or bump on the regualtor body. This bump points toward the prop. If its backward it will not allow fuel to flow.

Go here to see a new site I have been working on regarding tuning and tweaking these engines.

www.patternflyer.com

and check out my new Blog

Troy Newman
Team YS

windstar

My Feedback: (9)

Hi Troy,

Thanks for your comments. I do have the regulator bump pointing toward the prop. It has a new diaphragm and the plunger/silicone tip is also new and I have cleaned out the interior of the regulator. The pressure does hold in the tank as when I disconnect the line from the tank, the fuel squirts out pretty fast. Will check out your site and try removing the needle valve technique. Thanks again

RW

rc4j

My Feedback: (103)

Robert,
I sent you an email.
Jai