Welsh3D

I have a YS 63 that's recently been playing up.

It's about 8 months old and has seen fair use. Up until about last week it has been great, pickup was a little slow but reliable at least.

Last week it saw a slight loss of power, I thought no more of it, the last few days it's been losing RPMs during snaps and knife edges. Pickup is very slow and quite unreliable. Had 3 deadsticks tonight, these are the first 3 ever on my Yss.

Noticing that there was no pressure in the tank, I soon found a hole in the feed line,. fairly big. Definate cause of problem I thought. Fixed that and ran it again, no luck, ran exactly the same, and very little pressure in the tank.

There appear to be no more leakages anywhere, but I noticed that fuel pours from the carb, especially at idle.


I'm guessing the problem is to do with a regulator blockage?

Do these symptoms mean anything to you ??

If you think you know the solution, can you describe it to me please.



Many thanks in advance.

martup

Just a thought, but have you tried a new glow plug? If you have fuel filer etc. I would also check those for blockages, and if you don;t have a filter then there may be debri in the line.

Welsh3D

Good idea on the plug.

I have filters, but i'll check those anyway.

JWN

My Feedback: (42)

If fuel is pouring out of the carb, there is debris in the system. Most likely in the regulator under the plunger.

John

John Hawkins

My Feedback: (2)

Certainly check for anything holding the plunger open but this sounds exactly like the history of my 91FZ. The problem may be due to ring blow-by screwing up the regulator. Dave Shadel of Performance Products in the US suggested that this might be the problem with mine. I struggled with it for near a year until sending to him - where it is now. There is a modification they do that consists of drilling holes down from the top of the piston to the back of the ring land. Combustion gasses push the ring tight. You might want to post your problem in the YS engine support forum and see what he says.

crashlander

My Feedback: (10)

There may be debis in the check valve which is not letting close completely. Open it up and clean out. Be careful do not lose the diaphragm.

Orlando

The boys Back

Have you checked your tapits? there is wear and the biger the gap the less the valves open (there should always be a small gap about the size of a thin piece of paper)

Archie

Nathan..

Check all this stuff above..

The tappet clearance should be 0.1mm. using a 10 feeler gauge yu should be able to pull it through the gap with some friction when the piston is at tdc.

If you have not adjusted these since new they almost certainly need checking.

Some of the later checkvalves (last few years) have been known to cause probs where the plastic disc swells depending on fuel being used... make sure it can move freely in the barrel.. blow one end gently then the other... you should feel or hear the disc move.

As someone said, if you remove the diaphram / brass screw take care, and note which way round things go back. The screw should be reset so it is flush with the regulator body.
Do this clean up job in one hit and do not allow the diaphram to sit outside for long... you dont want it to dry out.
DO NOT put any oil in the regulator or anywhere in the system... it will block everything up and it will take a tank of fuel and mucking about to clear it all out.

The idle screw should be 1 turn out from fully closed, and main needle 1 1/4 to 1/12 turns out depending on how much Nitro is in use...

y63s are gems of motors.....

Welsh3D

Cheers.

I found a few problems. The checkvalve was stuck open, sorted. Next the regulator had a blockage. IF you screwed it in it didnt let any fuel pass and if you screwed it out it wouldnt stop the fuel flow... took all that apart and sorted those.

The problem now is that my pickup is rather slow. The idle is opne about 1 1/4 turn, the regulator screwed in about 2/3 turn from flush and the top end around 2/3 open. If i screw the top end in i lose revs. My fuel is currently Dynaglow 16. The last gallon of it which I used was perfect, but it seems to have lost its performance since I started the second gallon.

I've checked the tapets. You check them both with the motor reaching compresson right?

I have some Yamada 20% here which I'll try through it later.

Cheers.

Archie

Brass screw
This should be flush with the rim of the reg body... use a ruler or somat straight across the top to be accurate if you like. Should not need to go + or - 1/4 from here.

Idle screw should be close to perfect at 1 turn out from home.

Tappets, yes with poston at tdc you can check both, but do them individually as they can often be different.

Plug.. use YS, Enya 3, or OS F.

Yam 20/20 yes use this...Dynaglo not good... not enough oil and if memory serves oil is mineral based.


Only Monday I went to the field for a guy that said his YS 63 was pants... and it was....
I checked everything over, re set the needles and screws to these positions, adjusted tappets, and ran it on Yam 20.20 and it was perfect . not even a need to adjust the needles again once it was running... mind you everything was way cockeyed before ! so it wasnt hard to get some improvement...

Sprink

Dynaglow !?

That is only 10% oil (8% EDL and 2% Castor)

That is way below what is recomended by YS. In fact I don't know why Modeltechnics make it as 10% oil is way below the recommended amount of oil for all the engines I have come across.

At least change to something like Formular Irvine if you can't get hold of pure synthetic oil based fuel.

Welsh3D

I used to use coolpower in it then tried supaglow 10, that was fine, bought supaglow 16, not a whole lot better. Next time i got dynaglow 16, it was great,so when that ran out i bought another gallon. I was aware of the oil content, but it didn't seem to be doing any harm. (obviously not?)

Anyway, I'll try that yam 20.

djlyon

It does the harm slowly if your careful, suddenly if you're not. You need that oil to help carry away the heat from the internals of that small powerful engine. 10% won't do it. Anything less than 18% is a hazard. The operative word here is "small". The large engines have enough metal to get rid of the heat, the little guys don't.

I know you guys over there, on the island and on the mainland tend to run less oil than we do but you also usually run less nitro.

Again these little guys use oil as a coolant, not just a lub. When you cut down on oil your cutting the coolant.

Also YS doesn't rely on blow-by for lower end lubrication like the other 4 strokes. The lower end is the first stage of the combustible charge accumulator. If the ring gets worn the resulting blow-by is going to kill your power even if the engine feels like it has good compression.