zema carb question

[bandmiller2]

I've been reading some on rebuilding the zema carbs and they talk about the check valve.Is the check valve only used on carbs that have the primeing button or on all of them.This carb is off a 2000 vintage husky 55.They also mention not to use compressed air to blow out passages thats news to me its the first thing I grab.Whats the real story.?? Frank C.

[DigDug]

Its not a good practice to use compressed air  although I do everyday , but at a 16" distance as a light blow to get all carb cleaner out.    All different brands of carbs have different check valves scenarios.   The Zama you are talking about could have 3 check valves.   Two for the primer/purge ball  so it will work - one opens when you press bulb to push fresh fuel  and the second check valve opens on release of the bulb to pull fuel .    The third check valve is on the Low needle for idle help.   
There is a misconception the the primer bulb is for priming.   We have named it a primer and your owners manual calls it a primer.  But it is a purge bulb , as it purges the air out of the carb and fills it with fresh gas for better starting.   You actually need the choke on for more enrichment.    You can push the purge bulb 3 or 30 times it will not flood the saw and more than 3-4 pushes is doing nothing as  the gas is returned to the tank.    A  primer is more of a push pull button found on say a Skidoo snowmobile and it actually puts gas into the intake for enrichment instead of a choke.    Take this at a grain of salt not gospel , but it gives you the idea of what check valves are for.  So do not force compressed air into carb ports or it will ruin a check valve.    doug

[bandmiller2]

Thanks Doug, this carb doesn't have the pseudo priming bulb just the choke for enrichment.Also you'd think I could spell a four letter word its zama not zema. Frank C.

[DigDug]

WIthout a bulb your carb will have a main nozzle check valve  .   

[Al_Smith]

A primer bulb is not a bad idea .They have them on high end blowers like the Stihl Bg 85 and and Br 400 back pack and others .You only need to use them if the thing has sat idle for a while .If they didn't have them you'd be tugging on the rope until your  arm about fell off or so it seems after a while .

A saw is bad enough but something like a blower with a long fuel line it takes forever to suck the fuel out of the tank to the carb .