Miku carb questions ( & pic's)

G

GTO

#1
#1
This is whats on the Briggs 8HP with shaved head (and stuff) I Never messed with these carbs before but was having some flooding problems. If you left the gas line valve on over night the carb can leak slowly, the carb also floods easy if you crank it a couple times.

I was expecting some varnish in the bowl due to sitting but it was more like dist/dirt/grit. Both floats don't leak.



What are these holes for and should any of them be plugged to keep dirt out?





Also MDB, I figured out the cable thing but the return spring is to light to back the throttle down so a stiffer or extra spring is needed , I also need to rig a fitting at the top since the tube is way to small to putt any ball through.

BTW, is the throttle block supposed to go all the way down or is it meant to have a gap at the bottom in idle. Thanks.
 
J

jimh

#2
#2
Those holes are vents. Need to put hose on them and run them out a ways. I always shut off the fuel. When they're new it's not so bad, But after a while they usually give you flooding problems. Sometimes your choke valve doesn't seat perfectly. This let a little fuel flow too.
You should have a slight gap at bottom of slide at idle.
 
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G

GTO

#3
#3
Thanks for the info Jim. :thumbsup: I wonder if the float flap needs adjusting. looking at it, I cant tell if the choke is working or not because of the design . :doah:

What do you have them on? ATV's?
 
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J

jimh

#6
#6
If theres a gap ther you just about have to hold it up to a light or the sky to see it. The round slide ones look a little bigger, but whe your looking into the carb, you see the cutaway side.
 
65ShelbyClone

65ShelbyClone

Well-Known Member
#7
#7
All that dirt and crud is corrosion. I would say pull the float needle out and make sure there's no debris keeping it from closing all the way. If the needle isn't the problem, then adjust the float tabs. If they are too high, you'll probably get fuel coming out of the bottom of the float bowl through that little brass tube between the floats. I'm more familiar with Keihins, though.
 
J

jimh

#8
#8
Keihins are real bad about that. I like the way they run, but unless they're new or used daily, you'd better shut the fuel off. Thats a good habit anyway. If someone try's to steal it and ride away, they might not be bright enough to turn it back on.
 
65ShelbyClone

65ShelbyClone

Well-Known Member
#9
#9
A little Sta-Bil in gas will help too, but IMO fuel system corrosion is going to be more common in the future the more ethanol gets a foothold as an additive, especially in more humid climates. Alcohols are polar solvents and attract water like nuts.
 
G

GTO

#11
#11
Well, I should have got into the side panel of the carb, the choke is screwy and the bike starts right up without the choke but not with and I think the engine is running slightly choked. :confused: I also left the gas on to see hpow much it would leak and it left a little puddle. :doah:

Will have to get back in there, hope the carb kits are cheap for these.

Anyway, I let the kid ride the 8HP today with a helmet and his eyes bugged out when he let her out. :smile: we don't have enough street to try all the throttle. :thumbsup:
 
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