Oh, OK. Yeah trying to cut the little spring is probably a bad thing to do, it is quite sensitive in its tension. If you go that route, it may be better to try different springs from a Walbro carb rebuild kit instead. I haven't seen a need to mess with the spring tension. But yeah a little tiny piece of debris getting stuck in the fuel inlet valve does mess up the works good causing the engine to run too rich or flood out even. When it happened to me, I took the regulator apart and didn't see anything causing it. But when I re-assembled it, the regulator worked fine since. So I must have flushed the tiny spec of something out when I cleaned it.

I will post a picture of the spring I am using later in the day.

After you install the spring, the factory settings no longer work. Currently
I have the throttle in a normal idle position, the low speed screw is 1 turn
out, and the high speed is 1 1/2 turns out.

Next weekend I will post pictures and results of testing with a APC 10-6,
11-7, and 12-6 propellers.

I am also planing on testing the engine sometime in the next few weeks at
San Diego's Mission Bay. That way I can test the engine in the best atmospheric
conditions possible for this time of the year.


Bill M.

Just fired up another brand new YS 63 . Man it is so easy . Set the main needle right at 2 turns like all the others , flip the prop . Perfect fuel delivery . The thing runs greeeat ! Any time of year

But all of this has been fun too

Did you convert that YS-63 to gas and spark ignition?

Originally Posted by earlwb

Did you convert that YS-63 to gas and spark ignition?

Not a chance

Originally Posted by earlwb

Oh, OK. Yeah trying to cut the little spring is probably a bad thing to do, it is quite sensitive in its tension. If you go that route, it may be better to try different springs from a Walbro carb rebuild kit instead. I haven't seen a need to mess with the spring tension. But yeah a little tiny piece of debris getting stuck in the fuel inlet valve does mess up the works good causing the engine to run too rich or flood out even. When it happened to me, I took the regulator apart and didn't see anything causing it. But when I re-assembled it, the regulator worked fine since. So I must have flushed the tiny spec of something out when I cleaned it.

Also I have found the needle to be a bit sticky. Seems to be the arm from the needle to the diaphram binding in the slot on the needle

The WYJ spring part # 98-3160-7

Costs about .50 cents, same as jmaderoy predicted.

Originally Posted by Capt. Quirk

The WYJ spring part # 98-3160-7

Costs about .50 cents, same as jmaderoy predicted.

Thanks for the information. I appreciate it and I am sure others do too.

I flew the NGH 9cc engine equipped Escapade today as well as the Ugly Stick with the modified NGH 9cc engine. Both for several flights too.

I had to replace the regulator diaphragm as it softened up and stretched out over time and stopped regulating, same thing for the pump diaphragm too, as it got all stretched out too. So I suspect the stock NGH rubber diaphragms are made from a rubber compound that doesn't do well with our American pump gasoline over time. If you use SEF or TRU-Fuel the rubber parts might last longer. Anyway it was easy to swap out some Walbro carb diaphragms to fix the problem from a Walbro carb repair kit This might be what makes people think that the fuel inlet valve is stuck or something, when it may really be the diaphragm has softened up and stretched out on them. I had swapped out a second pump/regulator unit that worked well previously and it did the same thing. That was what prompted me to replace the diaphragms then.

I'll post a another video later. But I put a little brace on the pump/regulator on the Escapade to stop the unit from moving too much in loops and other maneuvers and that cured the lean out condition that would kill the engine. So it worked well today after the simple fix.

Your welcome Earl,

The spring makes the biggest difference, but I will post some other details on fixing
the vacuum leaks too.

Cool thanks again. If it helps anyone else, the spring is found in a carb like the Walbro WYJ-250, there are several others too, like the WYJ-192, WYJ-322 and so on.
http://www.ereplacementparts.com/wal...61_142036.html

I just went down the mower shop. He is out of 98-3160-7 but he had a grab kit with about 20 other types. Where do you start.

Originally Posted by GadgetEric

Well I squeezed mine in to. I am pretty happy with the way it looks.
Had to make a muffler extention and a few right angle nipples

Pitty I cant get it to run

Hi Eric,
thanks looks like a really nice plane. what plane is it?

As far as I can tell, there is only one spring used in the WYJ series. You may need
to order it. My spring kit does not include that #, but there are several that may work.
If you can verify a 30 psi pop-off pressure, that will get you in the ball park. I will test my
spring kit next weekend.

In the mean time, the standard spring appears to be 10.5 mm long, and the 98-3160-7
is approximately 7.5 mm long.

I also include two other pics; one of the fuel pump with the extra nipple for measuring
fuel pump pressure. And the second one with an extra nipple on the carb for measuring
venturi pressure.


Bill M.

Originally Posted by earlwb

I had to replace the regulator diaphragm as it softened up and stretched out over time and stopped regulating, same thing for the pump diaphragm too, as it got all stretched out too. So I suspect the stock NGH rubber diaphragms are made from a rubber compound that doesn't do well with our American pump gasoline over time. If you use SEF or TRU-Fuel the rubber parts might last longer. Anyway it was easy to swap out some Walbro carb diaphragms to fix the problem from a Walbro carb repair kit This might be what makes people think that the fuel inlet valve is stuck or something, when it may really be the diaphragm has softened up and stretched out on them. I had swapped out a second pump/regulator unit that worked well previously and it did the same thing. That was what prompted me to replace the diaphragms then.

I have noticed a difference in the diaphragms manufactured in China vs Japan. I am
testing with 87 octane unleaded regular, and Yamalube 2R oil. I will keep an eye on
the rubber parts. In fact, I think I'll incorporate an hr meter into my data acquisition
system.

Thanks

Bill M.


Note: Does anybody know what California adds to our fuel blends that may harm rubber parts
faster than other states?

Originally Posted by Boostoman

Hi Eric,
thanks looks like a really nice plane. what plane is it?

Its a Supersportster 40