| Author |
Message |
    
kayak
Senior Member
Username: kayak
Post Number: 81
Registered: 06-2016
| | Posted on Wednesday, December 07, 2016 - 05:34 pm: | 
|
I have a 8819b carb on my YT1 and took it apart last summer and blew out the passages, removed some crud etc. Just routine cleaning. On some recent tinkering with then engine and brief runs, I noticed fuel coming from the flame arrestor. I took it apart, made a new top gasket, cleaned and checked everything, reinstalled it. More fuel from the throat. This time I bought a "kit" which included a new float valve and seat, and factory gasket etc. I CONFIRMED the float was sealing by blowing into the fuel barb and turning the carb upside down. In fact the only problem was that the needle didnt like to disengage and this float doesnt seem to have a clip to pull it down, but thought I'd deal with that later since a vibrating engine would probably keep it from sticking closed very much. Reinstalled it, turned on the gravity fed gas. MORE fuel POURING from the throat.
I did a search and found this thread:
http://www.oldmarineengine.com/discus/messages/3430/102980.html
But it didnt seem to offer a 100% conclusion. Of course they mention that the float valve usually can only fail open due to debris. I have a fine screen on my fuel tank valve. I will try adding a clear plastic filter next just before the carb.
My question is whether there is something typical here that i dont know about.
Also regarding the gasket, looks like it may need another hole in the center as it seems to cover up the slow jet (see pics). When I made a gasket, I put a hole there. (The old gasket crumbled and I couldnt find that section of it by the time this question came up).
Any advice appreciated.
home made gasket
 |
kayak
Senior Member
Username: kayak
Post Number: 83
Registered: 06-2016
| | Posted on Thursday, December 08, 2016 - 03:41 pm: |
|
Ok while I wait for hopefully some advice on whether that gasket above should block the jet hole, I posted a video showing how the float operates properly with the bowl off, but when I attach the bowl, it will not shut off the fuel and the carb floods. The float is air tight, I "floated" it and shook it no fuel gets in. So it's not a sunk float. I know this probably means the float is catching somehow on the bowl, but when i blow into the fuel line with the bowl installed and turn the carb upside down, the flow stops.
So this is a minor gremlin but has me stumped at the moment and making me feel stupid!
https://youtu.be/KpH8kSOq7e8 |
ned_l
Senior Member
Username: ned_l
Post Number: 71
Registered: 08-2012
| | Posted on Thursday, December 08, 2016 - 08:25 pm: |
|
Are you certain that the way you have the gasket cut isn't interferiing with the floats rising completely? In addition to the slow speed jet hole you need to add holes for the other passages.
A very easy and accurate way to cut your own gaskets is to lay the gasket paper on the part and tap around the edges with a small ball peen hammer. ---- fast and accurate |
kayak
Senior Member
Username: kayak
Post Number: 85
Registered: 06-2016
| | Posted on Thursday, December 08, 2016 - 08:30 pm: |
|
hi ned, thanks. maybe I wasnt clear, I am now using a factory gasket, as I bought the "kit". It is the factory gasket which doesnt have a hole where that jet orfice is.
Also, the test video is with the new factory gasket on the upper half and the float seems to be working.
All that said, *something* is preventing the float from working when the bowl is attached. Just cant figure out what yet. |
ned_l
Senior Member
Username: ned_l
Post Number: 72
Registered: 08-2012
| | Posted on Thursday, December 08, 2016 - 09:15 pm: |
|
Oops,..... I didn't see the video |
david_doyle
Senior Member
Username: david_doyle
Post Number: 105
Registered: 03-2013
| | Posted on Thursday, December 08, 2016 - 09:25 pm: |
|
ned- Just used your tap-tap -tap method on a kind of complicated thin edge gasket that I had been avoiding. worked like a charm! thanks |
ned_l
Senior Member
Username: ned_l
Post Number: 73
Registered: 08-2012
| | Posted on Thursday, December 08, 2016 - 10:48 pm: |
|
I watched your video,..... and understand your dilema. I'm thinking about it, but don't have any thoughts yet.
When you have the bowl off and lift the float with your hand, how much effort does it take to shut off the gas? |
ned_l
Senior Member
Username: ned_l
Post Number: 74
Registered: 08-2012
| | Posted on Thursday, December 08, 2016 - 10:51 pm: |
|
Ahh,... good to hear. |
kayak
Senior Member
Username: kayak
Post Number: 86
Registered: 06-2016
| | Posted on Thursday, December 08, 2016 - 11:04 pm: |
|
ned, it moves easy and free. has to be some interference of the bowl, or the float is misshapen somehow. I'll have to play with it some more. maybe using water I am tired of smelling like gas! |
scott_n
Senior Member
Username: scott_n
Post Number: 286
Registered: 02-2008
| | Posted on Friday, December 09, 2016 - 01:56 pm: |
|
I had a slimmer problem turns out at the top of the bole their is a vent so the bole dos not get air locked.mime was blocked by a missing hole in the gasket. |
kayak
Senior Member
Username: kayak
Post Number: 87
Registered: 06-2016
| | Posted on Friday, December 09, 2016 - 04:29 pm: |
|
scott, after I saw your post I went back to see iof I took pictures the first time I took the carb apart to clean it in March. BINGO! The gasket has two holes in the center area not one. Maybe thats what you were talking about, I will add the hole and see if the float stops the flow. Thanks for the reply scott
 |
kayak
Senior Member
Username: kayak
Post Number: 88
Registered: 06-2016
| | Posted on Friday, December 09, 2016 - 05:13 pm: |
|
This shows where the new gasket was missing two holes. I added them with my gasket punch kit. Will try to run soon.
 |
kayak
Senior Member
Username: kayak
Post Number: 92
Registered: 06-2016
| | Posted on Sunday, December 11, 2016 - 01:00 pm: |
|
OK, the throat got a little wet but no leaking outside the carb after extended time with fuel turned on. I opened the carb drain plug and yes there was fuel in the float. Looks like it was Scott was right! 
 |
kayak
Senior Member
Username: kayak
Post Number: 93
Registered: 06-2016
| | Posted on Sunday, December 11, 2016 - 08:00 pm: |
|
small update, the carb is no longer spewing fuel but after short time, fuel does still accumulate in the throat and eventually drips out. I dont think the float level is high because it is not even level when the float needle seats. I am looking for a float setting spec.
also, the engine would still not stay running. have good compression by feel, and the timer activates the spark each compression stroke (although when turning by hand, sometimes the buzzer starts and stops indicating connection issue probably with the pitted saddle or spring roller contact) but it does spark every turn, so we must still have carbureter issue to resolve.
Finding zn NOS Zenith would be nice right about now! |
ernie
Senior Member
Username: ernie
Post Number: 2347
Registered: 01-2002
| | Posted on Tuesday, December 13, 2016 - 09:36 am: |
|
Chris,
The gasket MUST go under the 4 ears on the venturi. The gasket in this carb is exactly the same size as the round part of the venturi. The venturi is held tight in the groove in the carb bottom by the gasket. If it isn't the carb most likely won't work as it was designed.
Pics from an old carb that hasn't been taken apart until just now.
 |
ernie
Senior Member
Username: ernie
Post Number: 2348
Registered: 01-2002
| | Posted on Tuesday, December 13, 2016 - 09:40 am: |
|
The carb can drip fuel if the little tube in the above pic that goes from the gasket surface the the bottom if the inlet area behind the choke isn't clear. Its purpose is for the carb to suck up any extra fuel that may pool in the bottom of the intake behind the choke plate. |
