trouble pumping out: pick up tube problem
Posted: Sun Feb 22, 2026 1:35 pm
I've read all of the posts about pump out and have found our issue seems unique so wanted to post.
2003 hull#20
purchased 2025 from original owner
Issue: We've always had a difficult time pumping out the black tank; it would pump, but ridiculously slowly. Two main issues other's have discussed; poop pyramid/calcification and air vent obstruction. Accessed the vent, disconnected, and assured it was clear. Used a LOT of tank cleaner over months without help. It just seemed like something was occluding the bottom of the tube (you could pour water into the top of the pump out fitting and it wouldn't drain into the tank, or would drain slowly after hours). Looking at the factory schematics, the 1 1/2" tube has a 45 degree cut at the bottom, so it seemed the occlusion must be large.
Diagnosis: After flushing and clearing out the tank and pick up tube, I used an inspection camera to send down the pump out tube to discover what was occluding the bottom. To my amazement, the tube does NOT have a 45 degree cut at the bottom. The bottom of the tube is flat and sits flat against the bottom of the black tank leaving a ridiculously thin sliver of space. I would imagine the pipe was installed like normal without being cut first and this issue must have been occurring since the boat was brand new.
Questions: Has anyone else discovered this issue? What did you do about it?
Potential Solution: What I'm planning to do is buy a 3 foot long 1/4" threaded rod to use like a drill bit. I'll attach a small circular blade to the bottom (sandwiched between two nuts) to send into the pickup tube along with the camera and cut a notch in one side of the bottom of the tube. The blade only needs to cut plastic, so a modified dremel disc could be used (regular disc diameters are too wide for the tube). Also considering buying a somewhat soft metal washer (perhaps 3/4" diameter) and using the dremel to notch a cutting surface along the edge of the washer. I should be able to send the rod with camera to the base of the tube and, with the 1/4" rod in a drill, carefully cut one side of the tube enough to allow proper pumping.
Concerns: Don't cut the tank! Having the cutting blade about 1/2" from the tip of the rod should mitigate cutting the tank. Using the camera should be helpful to guide the careful process. I thought about just cutting 1/4"-1/2" off the bottom of the tube, but that would leave a ring of plastic in the tank that could occlude or jam the ball valve in the gravity drain tube in the bottom of the tank. This is why I think notching out one side should work better to keep from having to remove the ball valve tube to retrieve any cut material. For any debris left in the bottom, I plan on using a shop vac to clean the tank after the cutting project. I've found that a length of garden hose duct taped to an old shop vac hose works well to send down the pick up tube for clearing it out (what I did before inspecting with the camera).
I'll take some pictures of the process and can hopefully post them later as a follow up.
David
90 Degrees
2003 hull#20
purchased 2025 from original owner
Issue: We've always had a difficult time pumping out the black tank; it would pump, but ridiculously slowly. Two main issues other's have discussed; poop pyramid/calcification and air vent obstruction. Accessed the vent, disconnected, and assured it was clear. Used a LOT of tank cleaner over months without help. It just seemed like something was occluding the bottom of the tube (you could pour water into the top of the pump out fitting and it wouldn't drain into the tank, or would drain slowly after hours). Looking at the factory schematics, the 1 1/2" tube has a 45 degree cut at the bottom, so it seemed the occlusion must be large.
Diagnosis: After flushing and clearing out the tank and pick up tube, I used an inspection camera to send down the pump out tube to discover what was occluding the bottom. To my amazement, the tube does NOT have a 45 degree cut at the bottom. The bottom of the tube is flat and sits flat against the bottom of the black tank leaving a ridiculously thin sliver of space. I would imagine the pipe was installed like normal without being cut first and this issue must have been occurring since the boat was brand new.
Questions: Has anyone else discovered this issue? What did you do about it?
Potential Solution: What I'm planning to do is buy a 3 foot long 1/4" threaded rod to use like a drill bit. I'll attach a small circular blade to the bottom (sandwiched between two nuts) to send into the pickup tube along with the camera and cut a notch in one side of the bottom of the tube. The blade only needs to cut plastic, so a modified dremel disc could be used (regular disc diameters are too wide for the tube). Also considering buying a somewhat soft metal washer (perhaps 3/4" diameter) and using the dremel to notch a cutting surface along the edge of the washer. I should be able to send the rod with camera to the base of the tube and, with the 1/4" rod in a drill, carefully cut one side of the tube enough to allow proper pumping.
Concerns: Don't cut the tank! Having the cutting blade about 1/2" from the tip of the rod should mitigate cutting the tank. Using the camera should be helpful to guide the careful process. I thought about just cutting 1/4"-1/2" off the bottom of the tube, but that would leave a ring of plastic in the tank that could occlude or jam the ball valve in the gravity drain tube in the bottom of the tank. This is why I think notching out one side should work better to keep from having to remove the ball valve tube to retrieve any cut material. For any debris left in the bottom, I plan on using a shop vac to clean the tank after the cutting project. I've found that a length of garden hose duct taped to an old shop vac hose works well to send down the pick up tube for clearing it out (what I did before inspecting with the camera).
I'll take some pictures of the process and can hopefully post them later as a follow up.
David
90 Degrees