https://www.outdoorking-forum.com.au/forum/ubbthreads.php?ubb=cfrm Recent Topics en-us Wed, 14 Oct 2026 21:22:28 UTC 5 support@outdoorking-forum.com.au (OutdoorKing Repair Forum) UBB.threads https://www.outdoorking-forum.com.au/forum/images/general/default/rss_icon.gif https://www.outdoorking-forum.com.au/forum/ubbthreads.php?ubb=cfrm https://www.outdoorking-forum.com.au/forum/ubbthreads.php/topics/122528.html#Post122528
A few reasons below why they can flood

Blocked return/spill-back port (trapping the fuel instead of letting it flow back to the tank).

Thermal tank pressure / bad venting (pushing fuel past the pickup tubes continuously).

Mismatched or incorrect diaphragm spring tension (altering pump stroke/travel).

Mixture screw backed out too far (over-delivering through the low-speed circuit).

Choke butterfly staying partially closed (pulling a heavy siphoning vacuum).



The Return Hole Got Blocked: Inside the casting under that side cover, there is a tiny overflow/return port designed to let excess fuel spill back into the tank once the internal well is full (acting just like a float bowl overflow). If a gasket edge gets misaligned slightly, or if pattern-cut aftermarket gaskets cover that tiny return hole, the fuel has nowhere to go. It keeps pumping fresh fuel into the well until it overflows straight out the throat and down the valves.

Thermal Siphoning / Vapor Lock: As the metal tank and carb soak up engine heat for a couple of minutes, the air space inside the sealed tank expands. If the tank cap vent isn't clear, that pressure forces fuel up the pickup tubes continuously, overwhelming the metering wells regardless of the diaphragm's pumping action.

Checking that the return spill-back port is completely clear and unobstructed by the new gasket usually stops them from filling up plumb-full and drowning out.

the small spring tucked under the diaphragm is what controls the tension and travel of the pump paddle/actuator.

If the spring is too long or too stiff, it keeps too much constant pressure pushing the diaphragm inward, which can force the pump to stroke too aggressively or hold a valve open longer than it should. On the flip side, if it's incorrect or mismatched, it upsets the delicate pressure balance against the crankcase pulse, altering the stroke and letting fuel continuously creep or flood into the well instead of metering correctly.

Getting that exact spring tension right—or making sure an aftermarket kit didn't supply a generic spring that's throwing off the pump travel—makes all the difference in stopping that warm flooding.

1. The Mixture Screw (Idle/Low-Speed Adjuster)
How it affects flooding: On these carbs, the idle mixture screw meters the fuel drawn up from the idle well. If the screw is backed out too far (too many turns open), it creates a wide-open path for fuel to feed through the low-speed circuit.

Combined with a warm engine or tank pressure, excess fuel rushes through that circuit unchecked, loading up the cylinder and contributing to the flood. (Standard initial setting is usually seated lightly and backed out about 1.5 to 2 turns).

2. The Choke Butterfly Staying On
How it affects flooding: If the choke butterfly is even slightly partially closed (or if the linkage/stop is bent so it doesn't open 100% when pushed off), it acts like a permanent choke.

The Result: As the engine runs, a partially closed choke creates a massive vacuum pull right at the throat. That high vacuum acts like a siphon, drawing an enormous amount of raw fuel straight out of the jets, instantly flooding the engine and killing it within a couple of minutes once it's warmed up.

Cheers
Max.

]]> Fri, 02 Oct 2026 09:18:58 +0000 maxwestern https://www.outdoorking-forum.com.au/forum/ubbthreads.php/topics/122528.html#Post122528 https://www.outdoorking-forum.com.au/forum/ubbthreads.php/topics/122526.html#Post122526 That would help to see what you're seeing.

]]> Fri, 02 Oct 2026 08:24:19 +0000 looktall https://www.outdoorking-forum.com.au/forum/ubbthreads.php/topics/122526.html#Post122526 https://www.outdoorking-forum.com.au/forum/ubbthreads.php/topics/122506.html#Post122506
]]> Sat, 12 Sep 2026 09:48:09 +0000 NormK https://www.outdoorking-forum.com.au/forum/ubbthreads.php/topics/122506.html#Post122506 https://www.outdoorking-forum.com.au/forum/ubbthreads.php/topics/122483.html#Post122483
I'm new here.

I thought I'd share this with you if you don't have a copy Briggs & Stratton Repair Manual

Cheers

]]> Mon, 17 Aug 2026 07:53:05 +0000 Oldeyes https://www.outdoorking-forum.com.au/forum/ubbthreads.php/topics/122483.html#Post122483 https://www.outdoorking-forum.com.au/forum/ubbthreads.php/topics/122263.html#Post122263
Put a coat covering all the welds and now all is good.

Although the pump is only 3 years old a spare tank was not available which seems poor form - Bianco BIA-WP15A - but now that I found several of the welds had leaked it was probably a good thing they don't supply spares as a new one may have developed leaks down the track.

]]> Fri, 20 Mar 2026 06:37:21 +0000 MowingManiac https://www.outdoorking-forum.com.au/forum/ubbthreads.php/topics/122263.html#Post122263 https://www.outdoorking-forum.com.au/forum/ubbthreads.php/topics/122114.html#Post122114



]]> Sun, 11 Jan 2026 21:30:21 +0000 AVB https://www.outdoorking-forum.com.au/forum/ubbthreads.php/topics/122114.html#Post122114 https://www.outdoorking-forum.com.au/forum/ubbthreads.php/topics/122217.html#Post122217
]]> Thu, 05 Mar 2026 21:32:47 +0000 mm-mowers https://www.outdoorking-forum.com.au/forum/ubbthreads.php/topics/122217.html#Post122217 https://www.outdoorking-forum.com.au/forum/ubbthreads.php/topics/121899.html#Post121899
]]> Tue, 04 Nov 2025 21:17:02 +0000 NormK https://www.outdoorking-forum.com.au/forum/ubbthreads.php/topics/121899.html#Post121899 https://www.outdoorking-forum.com.au/forum/ubbthreads.php/topics/121477.html#Post121477 I will do as you suggest and update in 48 hours or so. Gary

]]> Sun, 11 May 2025 08:42:21 +0000 Gary8600 https://www.outdoorking-forum.com.au/forum/ubbthreads.php/topics/121477.html#Post121477 https://www.outdoorking-forum.com.au/forum/ubbthreads.php/topics/121314.html#Post121314 Clean both the breather hole and tube oil free.
Apply JB-Weld when inserting the tube.
Position the tube toward the rubber elbow.
Let it dry for 48hrs.

]]> Tue, 08 Apr 2025 07:16:15 +0000 thecarbymaster https://www.outdoorking-forum.com.au/forum/ubbthreads.php/topics/121314.html#Post121314