Pump and Weir Type Carburetor Won't Suck Gas

The rings could be worn out or the carburetor may need cleaning...Has the motor ever been rebuilt....? 41 years old....

"The rings could be worn out or the carburetor may need cleaning...Has the motor ever been rebuilt....? 41 years old…."

I cleaned the carburetor but have not checked the rings extensivly. It was on the property when i bought it about 20 years ago and i have never serviced it or anything but i do not nkow what had been done to it previously. It has been sitting outside the whole time. I was able to get it to start and run but only off the gas in the second resivoir.

Have you checked the pump valves? Some types I remember had discs which could be turned over to give a new lease of life.

I will check! thanks for the advice

Even a tiny leak in the fuel suction line can make the pump ineffective.

It will run off fuel i have poured into the intake but i have not tried filling the tank completely

If you check some of the small engine repair parts sites, or maybe even Sears, you may be able to get a complete carburetor kit and that is highly recommended. Or even install a new carburetor. One last trick is this fluid called "Starbrite" in a light blue plastic bottle at most automotive retailers, especially O'Reilly. It will help break up any varnish deposits that may have screens plugged, but judging by the age of the engine, this carburetor was never intended for use with gasohol fuels. The old generation of materials will embrittle and crack, rendering them useless.

Another thing: since fuel is making it up to the upper reservoir somehow, it could be the fuel flow needle valves are fouled with varnish. Try the fluid I mentioned above, and I do approve this message.

Here is a repair guide.

http://outdoorpowerinfo.com/repairs/briggs_pulsa-jet_horiz_fixed.asp

If it has set that long not running the diaphram that makes up the pump is at the least hard as a rock. If not cracked and broken.

I just took apart the carburetor to find that the diaphram was comepletly intact and still very flexible. It suprised me but now what

Get a bottle of Starbrite and cross your fingers. Also remove the needles and clean them and the tiny orifices (jets) and then maybe you can gas to flow. Or you be stuck looking for pinholes in vacuum side stuff for a while, or get a new carb.

Ive had the air filter off when messing with it just so i can get a good look at the carburetor and choke but thats an awesome checklist. I will look at all of them and see if i can find the problem. thanks again

Here's a better site showing just the Pulsa-Jet pump part.

You don't say where you are located, but in America, the biggest problems with engines that sit for a while is ethanol fuel. Until I started using an ethanol free fuel, I was always fighting with carburetors in the spring. The ethanol does weird ting to gaskets and seals in older engines. On a older Briggs, sitting through one winter, there was something that looked like tar in the fuel pump, had to rebuild the carb. No problems after I started using ethanol free gas in all my small engines.

I disagree with the ethanol blaming.

I've been running E30 or higher in all my engines for years, 1940's JD a tractor to 2016 MTD four stroke trimmer and everything in between, while my brother and dad run the ethanol free stuff and I have found that we all have the exact same problems with fuel systems.

Fuel lines rot out after a year or two, fuel goes sour after a few months and anything that sits for a long time gets plugged up with sticky rotten fuel varnish and crusty crap. E30 or E free they both have the same end results.

Around here I know for sure it's the gasoline blends that are to blame not ethanol the only things that survive it are the old machines that have all metal fuel systems from the tanks through the carburetors but they still get that varnish and crap build up if I don't shut their fuel off and let them run their carburetors dry before parking for winter.

I was able to find a replacement fuel tank and carb as a unit from NAPA. It solved my water rotted fuel tank.

A tiny hole in the tank allowing air in, is probably the problem, or even in the suction pipe, but above the level of the lower tank!, The list is long. Using a bicycle pump and connector, search for small air leaks with soapy water. I usually use washing up liquid mixed with water, about the same strength that a child can use to blow fine bubbles!!

When found, clean the area(s?) around the hole(s?) with say denatured spirits (remove any rust with some abrasive means first), then cut tiny patch of some material, I have used part of an old cotton shirt for example (, but its mostly unimportant what the material is), and using 2 part epoxy, make sure it is fully encased in epoxy! Leaving it in hot sunlight promotes fast hardening.

I have used such small repairs for over 50 years on many things, often cars, none have failed me in any way whatsoever....provided it is on a part that does not flex.....for those, you need something else!

I hope this helps....

Water in the tank? You may have a fuel line with water blocking the flow of fuel.

I have experienced a similar problem and found that fuel lines can close up, restricting the fuel flow. I Suggest you replace the fuel lines.

The fuel pump diaphram gets old and brittle, especially if it sets with no fuel in it. It is on the side of the carb. -- JHF