HOW TO CONVERT A BRIGGS TWIN CARB FOR EXTERNAL PUMP.

[Arkie]

The easy mod is for the 3 and 4 screw type Briggs twin carbs that has the fuel pump intregal with the carb and mounted to the front of the carb. (The wimpy type fuel pump that has habits of going bad quite often.

A guy gave me a really nice clean carb off a Briggs opposed twin carb that he broke a ear off for one of the 3 pump screws.

Take the top off the carb and the front fuel pump. You will notice on the throttle side of the carb a non-threaded hole for a 1/8 barb fitting. This hole is in-line with the carb body gas inlet but it's not drilled into the inlet. This hole is in-line with the gas in-let hole from the front pump. You can do this mod W/O a drill press if desired by being careful.
Use a drill bit about same size as the front pumps outlet hole on the front of the carb's body and drill the bottom of the 1/8 inch side hole to intersect the carb bodys gas inlet hole. I used a drill bit stop but really not necessary if you just drop another drill bit or similiar into the hole to stop the drilling bit.
Then take a good sharp 1/8 inch NPT pipe tap and carefully thread the side inlet for a 1/8 inch NPT hose barb brass fitting. Start the tap straight and reverse the tap quite often when threading so as to get good clean threads and not ruin the threading process. Gently install the flat part of the carb body in a vise when drilling and threading.
Then tap the front pump outlet hole for A 10/32 machine screw and use a seal washer on the screw. The hole is already proper size for a 10/32 tap bit.
Install and external pulse fuel pump and use the pulse hose from the removed front pump.

Clean all the aluminum filings from the carb body.
Re-install the top and you now have a more reliable fuel pump/Carb system and not have to buy any more of the 3 and 4 screw wimpy Briggs carb pump kits.

I had always wanted to try this mod and this carb with broken fuel pump front mounting was a good one to do the test mod. Once you do one it' only takes about 30 min if you have a drill, taps, and a bench vise.

[38racing]

interesting. I had thought just removing the check valves and diaphragm on the 4 bolt might work. I actually just bought a 4 bolt block from aliexpress for 14$cdn. but the rest of a kit was 28$ cdn . only way to get replacement needle. so far the Chinese replacement carb is working. just about to put deck back on this rider. had to rig an ayp chute onto a murray. briggs wants 140 for the chute.

[Arkie]

That is an easy carb mod once you take the pump off and the top off the carb and inspect.

If you are talking about buying/replacing a discharge chute, their prices are out of sight and quite a few replacement chutes are not OEM quality. I have a big roll of fiberglass re-enforced rubber matting about 3/32 inch thick and I've repaired quite a few of them chutes that are cracked and going away with that matting using pop rivets. The matting is strong flexible and riveted to the top of the chute.

I started adding a 1/4 eyebolt to the chute and a bungee cord attached to the tractor to some of mine and when I do not need the discharge chute when out away from house I just tie it up vertical with the bungee. (can reach the eyebolt and un-hook the bungee and drop the chute when needed.
Some of them replacement plastic chutes will just break off instead of flexing if if hooks a solid object.

Seems China is catching on to how to make stuff so as it looks better than in the past but fails after awhile. Failure rate not as fast on some things made in China but still a failure.