YS 91 Help
08-23-2005 | 02:52 PM
#1
Thread Starter
Senior Member
My Feedback: (16)
Joined: Oct 2002
Posts: 129
Likes: 0
Received 0 Likes
on
0 Posts
From: Lakeview, AR
YS 91 Help
Does anyone here know anything about a YS engine? This is a learning curve for me.
I bought the thing used and in great shape but the guy i bought it from could not get it to run. I found it to be a challenge.
I got it and replaced all of the gaskets, diaphragm, reset the valve clearance to between .004 and .01, and and did a thorough inspection. I then got on the net and found all the settings for the needles and regulator and set up the check valve pressurized fuel system. Used a syringe to check for leaks.
I fueled the tank up and started right up and ran like a dream for a min or two. As the fuel level started to drop the engine began to richen up. I chased the high speed all over the place and I could not get it to run correct. The engine bogged and died. I fueled it up again and again she ran great at first. then back to the same routine. I think that it either is a heat problem or something with the screwy fuel system.
I called a guy over to look at it that has been running YS engines for a while and he could not figure it out.
I just hope this rings a bell with someone.
Thanks to all
I bought the thing used and in great shape but the guy i bought it from could not get it to run. I found it to be a challenge.
I got it and replaced all of the gaskets, diaphragm, reset the valve clearance to between .004 and .01, and and did a thorough inspection. I then got on the net and found all the settings for the needles and regulator and set up the check valve pressurized fuel system. Used a syringe to check for leaks.
I fueled the tank up and started right up and ran like a dream for a min or two. As the fuel level started to drop the engine began to richen up. I chased the high speed all over the place and I could not get it to run correct. The engine bogged and died. I fueled it up again and again she ran great at first. then back to the same routine. I think that it either is a heat problem or something with the screwy fuel system.
I called a guy over to look at it that has been running YS engines for a while and he could not figure it out.
I just hope this rings a bell with someone.
Thanks to all
08-23-2005 | 11:06 PM
#3
My Feedback: (21)
RE: YS 91 Help
Does the engine look like this, with the air chamber on the back ? 91 FZ ?
Remember that the fuel level in the tank does not effect how the carb acts....like
on some "regular" engines. Is the one way valve installed correctly ?
Set the reulator screw flush with the case. Set both needles at 1 and 1/2 turns out.
FBD.
Remember that the fuel level in the tank does not effect how the carb acts....like
on some "regular" engines. Is the one way valve installed correctly ?
Set the reulator screw flush with the case. Set both needles at 1 and 1/2 turns out.
FBD.
08-23-2005 | 11:27 PM
#4
Senior Member
My Feedback: (6)
Joined: Mar 2002
Posts: 1,815
Likes: 0
Received 0 Likes
on
0 Posts
From: Lincoln,
NE
RE: YS 91 Help
From your description of needle swings, my first guess would be regulator sticking open. I notice you replaced the diaphram, which is good, but it is possible there is gunk on the valve seat in the regulator. Taking it apart and cleaning may solve the problem. The parts you need to check are behind the brass adjustment screw. Be aware there are some very small parts in there.
Also be sure your prop is tight and you are not using a plastic spinner backplate. A slightly slipping prop can cause a needle chasing exersize... been there done that.
Also be sure your prop is tight and you are not using a plastic spinner backplate. A slightly slipping prop can cause a needle chasing exersize... been there done that.
