Monarch Shaft Driven Water Pumps & Repair Parts
- AOT, ACT, BSTF, MIT, NT3M9 and TT bare-shaft pump ends
- Runs from a belt, coupling, PTO shaft or hydraulic motor
- Ports from 1 inch up to 4 inch NPT
- Confirmed Franklin Electric matches: FAOT, FACT, FMIT and FTT
- Repair parts listed by reference and code number
- Send us the data plate details and we will match the part
Your tractor, engine or electric motor still runs fine, but the pump end bolted to it has started to leak or lose flow. That pump end is a Monarch shaft driven pump, a bare pump on its own bearing frame that something else has to turn. This page covers the AOT, ACT, BSTF, MIT, NT3M9 and TT series, their Franklin Electric versions, and what we need from you to match a part.
Keeping the drive you already own saves the cost of a new motor or engine. Match the shaft, ports and rotation.
Repair or Replace a Monarch Shaft Driven Pump?
You can keep a Monarch shaft driven pump running with repair parts while stock lasts, or swap in its Franklin Electric version. Four of the six have a confirmed Franklin match: AOT to FAOT, ACT to FACT, MIT to FMIT, and TT to FTT. For the BSTF, the Franklin FBSTF is the matching frame-mount self-primer, so confirm it with your data plate.
AOT, ACT, BSTF, MIT, NT3M9 and TT Specs Side by Side
| Series | Type | Suction x discharge (NPT) | Top published output | Franklin version |
|---|---|---|---|---|
| AOT-4, AOT-5, AOT-6 | End suction centrifugal, open face iron impeller | 1¼ x 1, 1½ x 1¼, 2 x 1½ in. | AOT-6: 135 GPM at 30 ft (3 HP, 3450 RPM) | FAOT-4, -5, -6 |
| ACT-5SD, ACT-6SD, ACT-8SD | End suction centrifugal, enclosed impeller, built for pressure boosting | 1½ x 1, 1½ x 1¼, 2 x 2 in. | ACT-8SD: 170 GPM at 30 ft (5 HP, 3450 RPM) | FACT |
| BSTF-51, -82, -83, -125 | Self-priming centrifugal on a frame | Check your data plate | Seal size 5/8 in. I.D. (51, 82) or 1 in. I.D. (83, 125) | FBSTF (confirm with your data plate) |
| MIT-20, MIT-30, MIT-40 | Self-priming semi-trash, replaceable wear plate | 2, 3 and 4 in. | MIT-40: 760 GPM at 20 ft (15 HP, 1750 RPM) | FMIT-20, -30, -40 |
| NT3M9 | End suction centrifugal, back pull-out casing | 4 x 3 in. NPT, or Victaulic | 930 GPM at 130 ft (40 HP, 2600 RPM) | None confirmed |
| TT-20, TT-30, TT-40, TT-60 | Self-priming trash pump, replaceable wear ring | 2, 3 and 4 in. (TT-20 to TT-40) | TT-40: 740 GPM at 60 ft (2400 RPM) | FTT-20, -30, -40; TT-60 moves to FTT-40 |
Flow figures come from the Monarch performance charts for each series. Head is total head in feet, including friction loss.
Belt, Coupling, PTO or Hydraulic Motor: How Each Series Is Driven
A shaft driven water pump has no power of its own. The listing for each series names the drives it was built to take.
- Belt drive: the AOT, ACT and NT3M9 take a belt and pulleys. Pulley sizes set pump speed, and the charts list output at more than one RPM.
- Direct drive: the AOT, ACT, BSTF and NT3M9 connect to an electric motor or gas engine through a flexible coupling.
- PTO drive: the NT3M9 listing names power take-off drive, which suits a tractor PTO water pump setup.
- Hydraulic motor: adapter kit 612881 couples a hydraulic motor with an SAE J744C flange to the MIT-40 and TT-40. Kit 612880 does the same job for the NT3M9.
Shaft size decides whether your coupling or pulley fits. The AOT, ACT-5SD and ACT-6SD use a ¾ inch shaft with a 3/16 inch keyway, and the MIT-40 uses a 1 5/8 inch shaft. The NT3M9 comes in standard and counter-clockwise rotation, so check which way yours turns.
Clean Water, Grit or Solids: Where Each Series Fits
The water you move decides the series. Clean water and pressure point one way, while sand, silt and solids point another.
AOT and ACT for Boosting and Clean Transfer
Both lines use thick-wall cast gray iron casings made for pressure boosting. The AOT has an open face iron impeller, and the ACT-5SD and ACT-6SD use glass-filled Noryl impellers.
The standard seal on both is Buna with carbon and ceramic faces. For fertilizer and chemical work on the ACT, the listing calls for seal 240369 in stainless steel and Viton.
NT3M9 for Water Trucks and Ag-Chemical Loading
The NT3M9 is the largest pump here, with a 9 inch impeller and a 4 inch suction. Its listing names water trucks and liquid ag-chemical bulk loading as its main jobs.
All-iron seal models carry a Viton mechanical seal and a stainless steel shaft sleeve. You can also order gland packing instead of a mechanical seal.
BSTF and MIT When the Pump Sits Above the Water
Both series prime themselves, so the pump can sit above the water source. The MIT adds a semi-open impeller that handles mud, sand or silt up to 10% by volume.
The MIT also has a built-in check valve, a priming plug, and a replaceable steel wear plate. That plate is the part to watch on gritty jobs.
TT Series on a Bearing Frame
The TT is a trash pump that happens to be shaft driven, so it shares this page with the others. It uses a two-vane enclosed impeller and a wear ring instead of a wear plate.
TT wear parts, the TT to FTT cross-reference, and the TT-60 swap to an FTT-40 live on our Monarch trash pump parts page.
When a Bare-Shaft Pump Is the Wrong Buy
- You have no engine or motor to drive it. A Monarch gas engine pump comes with the engine already mounted.
- You want a plug-in pump with no belts or couplings. Look at the Monarch electric motor pumps instead.
- Your pump end is cracked or parts have run out. The current Franklin frame mount self-priming pumps replace the MIT and TT lines, and the FBSTF is the BSTF match to check.
What to Send for a Quote
- Model and type from the data plate, such as AOT-5 Type B or NT3M9S-CCW.
- Order number if you have it, such as 615121 for an AOT-5.
- Reference and code number of each part from the parts list.
- Drive details: belt, coupling, PTO or hydraulic, plus shaft size and rotation.
The listings ask for model, type, code number and part description on every order. That way the part matches the pump you own.
Frequently Asked Questions
What drive types work with the NT3M9 pump?
The drive types that work with the NT3M9 pump are belt drive, power take-off (PTO) drive, and direct drive through a flexible coupling. For a hydraulic setup, adapter kit 612880 couples a hydraulic motor with an SAE J744C flange to the pump. The NT3M9 comes in standard and counter-clockwise rotation, so match the model to the way your drive turns. The chart lists 1750 and 2600 RPM, so set your pulleys or gearing to land near one of them.
Can the NT3M9 handle agricultural chemicals?
Yes, the NT3M9 can handle agricultural chemicals, and its listing names liquid ag-chemical bulk loading as a main job. The seal models use a Viton and stainless steel mechanical seal with a stainless steel shaft sleeve to resist corrosion. Gland packing models use packing rings instead of a mechanical seal. When you order a seal, tell us whether your pump is an NT3M9S (seal) or NT3M9P (packing), plus the rotation and port type.
Can I put a Franklin pump end on my Monarch belt drive?
Yes, you can put a Franklin pump end on your Monarch belt drive when the series has a confirmed match and the shaft, ports and rotation line up. The AOT listing shows full parts interchange with the FAOT. The TT-40 and FTT-40 both use 4 inch NPT ports and ship at 420 pounds. A TT-60 needs coupler adapters to move to an FTT-40. Send us your shaft size, key size and rotation, and we will confirm your pulley still fits.
Ready to order? Send us the model number or the data plate details, and we will confirm the right Monarch part or Franklin Electric pump before it ships.