Pulsa-Prime Not Priming

[Merkava_4]

Model : 10M902
Type : 0489 E2
Code : 05101754

The primer bulb is not torn, so I don't know why it's not priming. I got the carb completely taken apart which is something I usually do at the end of Winter anyway. The fuel pump diaphragm and gasket are a little stiff, so I will change them out. I wish I had the special pliers for the primer bulb. I'm going to look into getting some. What do you guys think about the knock-off Chinese diaphragms and matching gaskets on eBay ? I'd never get a knock-off carb, but I don't know about the diaphragms.

[KE4AVB]

Though rare it can be the primer check valve not working. I only seen a few but I don't see many of these older carbs anymore. Basically it is because locals are not using push mower much; just string trimmers. Also make you are installing the diaphragm next to the tank side.

Yes you have to remove the primer bulb to access this check valve setup. On the ipls it is item 913.

[Merkava_4]

KE4AVB,

You ever try one of those unbranded diaphragm kits from eBay? Item 394 on the drawing.

[KE4AVB]

KE4AVB,

You ever try one of those unbranded diaphragm kits from eBay? Item 394 on the drawing.

No sir U have not. The only after market version I used were the Stens 520-175 and I haven't even use one them since 2020. Just no mowers came that need one.

[bgsengine]

1) Probably won't need to pop out the primer bulb itself just yet - Most often the reason for no prime is a warped tank or carburetor body
2) diaphragm to tank side, gasket goes carb side (easy to put them wrong)
3) If you put a new diaphragm and gasket kit on it (and those aftermarket ones you can get on amazon are same as the Stens ones, they all work quite well usually) make sure and save your OLD gasket if you can keep from damaging it
4) Check tank for flatness - straightedge across it and if you can fit a .002 feeler gauge under straight edge at any point, tank is warped
5) Very very common to have those nylon body carbs come in with the screws having been over-tightened (and not torqued in a pattern) which causes the nylon carburetor body to warp (and eventually the tank surface follows)
6) DO NOT overtighten the screws - start with the screw closest to carb body and go counter-clockwise around, just fingertips ion screwdriver to snug them in a circular pattern, then go back over them with just a bit more torque (but not ham-fisted crank-down tight!) fingertip tight is enough
7) after putting new diaphragm and gasket in place and it still won't prime, pop carb off and inspect gasket for impression of the sealing bead that is molded into carb body and you'll probably visually see where it is not fully seating (indicating carb or tank or both are warped) Minor warp can sometimes be resolved by doubling up on the gasket (Some D&G kits come with 2 gaskets for that reason!) if doubling up gaskets, add just a tad more torque to the screws to help further compress the gasket material . Severe warp can sometimes be corrected by finding the point at middle of carb gasket that isn't seating fully and cutting a piece of old gasket in that area to "thicken up" and use a razor or Xacto knife to feather the edges thinner to smooth out the connection between gasket material thicknesses.

In my many years working with those carburetors, I have only ever ONCE had to replace the check valve (and it's a pain in the ass to do anyways) because the steel ball rusted and spring broke. (it sat through a flood and then sat in the weeds for a couple years) Don't really need the pliers to pop out the bulb if you have replacement bulb and retainer (The better aftermarket ones come with new retainer) - just pop em out with screwdriver one side at a time (bit by bit on each side) - MUCH more handy if you are gonna buy a tool for them, is the primer bulb INSTALLER (too easy to stab a hole in bulb when trying to seat thing swith a screwdriver)

[KE4AVB]

See BGS this why we need multiple viewers. We all can have different experiences ( run different problem with the same setups. I personally never ran across a warped version of this carb but did replace a lot of diaphragms and several of the check valves, never ran across one rusted but that is possible with steel involved.

Even every area in the country have different sets of problems that we regularly deal with.

[Merkava_4]

Thanks for the info bgsengine.

I found that primer bulb installer tool. It looks like it might be made out of plastic and I'm guessing it's used with the palm of your hand for driving the primer bulb in.

[bgsengine]

Thanks for the info bgsengine.

I found that primer bulb installer tool. It looks like it might be made out of plastic and I'm guessing it's used with the palm of your hand for driving the primer bulb in.

Yup. correct on all counts. It helps push everything in squarely and evenly so the sealing bead of the bulb fits perfectly into the groove with even pressure all around until retainer clips "snap" into their slots on the carb.

[Merkava_4]

There's several unbranded diaphragm kits on eBay for sale. One of them is only $1.49 + $0.60 shipping.

Would you guys jump ship or would you buy Genuine Briggs & Stratton ?

eBay Item Numbers :

325980463859

324670841648

166242543963

252617591083

[bgsengine]

There's several unbranded diaphragm kits on eBay for sale. One of them is only $1.49 + $0.60 shipping.

Would you guys jump ship or would you buy Genuine Briggs & Stratton ?

eBay Item Numbers :

325980463859

324670841648

166242543963

252617591083

I'd focus on the seller by going to their feedback pages and read a month's (or 3 month's if they don't have a lot of feedback) comments and look for clues that they're a sorta specialized OPE seller and not just re-selling someone's old stock.

Old stock that has not been stored well (hot storage unit or the like) gaskets and diaphragms tend to get brittle and fall apart easily. I'd be surprised if the no-name or aftermarket parts did not come out of the same exact factory assembly line as the Briggs OEM ones... especially these days when those d&g kits are getting near to obsolete (Though Briggs still sells the even older pulsa-jet and vacu-jet diaphragms - last I knew of in 2019, that is....) Bear in mind the cheap shipping option usually means it ships from china (takes weeks or months to get here) or it goes in a stamped envelope (no tracking, and no guarantee it doesn't come smooshed, mashed or folded) - you DO get what you pay for....