YS63 FZ plunger
 

I ordered a YS 63 FZ plunger from Central Hobbies, their part# YS1145 as shown on their blowup diagram at http://centralhobbies.com/Engines/parts/YS63FZEx.html. Anyway, the plunger that came is about half the size in diameter as the one in my engine.

YS Parts and Services shows part# YS4405 on their website @ http://yspartsandservice.com/pdf/FZ63.pdf.

Anybody know what the deal is on that?
What is the correct part#?

RE: YS63 FZ plunger
 

3D,
YS at one point went to a larger plunger for the crank case mounted requlators. They eventually went back to the smaller plunger because the larger ones were binding up on the regulator housing. The concept behind the larger surface area was that the diaphram would last longer, however with the issues surrounding the larger plunger the wear issue wasn't as big a deal. I've known some YS owners to "take a little off" the larger plungers surface area to lessen this problem, or as I did on my 110's, just replace with the smaller version. Either way, you will be fine with the smaller version.
Skids

RE: YS63 FZ plunger
 

Well Central Hobbies should update their website and indicate its not a 100% equivalent replacement product. My regulator has a ledge the larger diaphram rests on and keeps it more "stable" against vibrations. Furthermore, the wear pattern on the diaphram is going to be different with a different sized pluger....so you need to be warned that you should replace the diaphram as well.

I have never had any "binding" issue with my regulator in 6 years of almost weekly use.

RE: YS63 FZ plunger
 

You are correct with regards to the wear pattern on the diaphram, however, these things seldom need replacement with the smaller plunger as well. As for the large vs. small plunger, if your larger one works then keep using it, if it has stopped working then the smaller one will work just as well. I read somewhere that the diaphrams seldom need replacing and that most guys would only replace when doing regular maintence. The diagram shown on the Central hobbies site is that of the original 63 FZ, I would assume that you have an updated version (larger plunger) and I would bet that the diagram that came with your motor does not show the change.
Skids

RE: YS63 FZ plunger
 

I already paid for the smaller plunger...
The problem is whats the chances that it leaks now with the diaphram that is 2 months old with the larger plunger?

The point is that YS and Central should put something on their websites about this..... So someone knows they might want to purchase the diaphram and not have to wait 5 days to get a different one then expected and have to place another order now and pay shipping for a diaphram after the fact because they are not shipping the same thing that came with the engine originally.

Its just poor customer service in my book.

RE: YS63 FZ plunger
 

I understand what you are saying.

If the diaphram you have isn't deformed you can still use it. When they get "streached" out is when you would look to replace. In other words if the diaphram is still flat then continue using it and you should have no problems. If you can take a picture of it I would be more than happy to let you know my thoughts on if you should replace.
Skids

RE: YS63 FZ plunger
 

No its got the bubble impression of the opening...but that happens really quick in my experience. In fact in this one, it happend in 2 months and only about 20 tanks or so of fuel.