Fuel Sending Unit 240-33 ohms 13in Reed Switch Sender - Durable Fit

In this review the 100TECH 240-33 ohm fuel sending unit is examined for boat and vehicle owners who need a reliable replacement sender. The bottom line: it is a straightforward, durable direct replacement for arm type senders that excels because it uses an OKI reed switch imported from Japan, eliminating delicate moving electronics and reducing maintenance. Installers looking for a solid steel sender with American standard output and clear instructions will find this unit practical and dependable.

Key Features

• OKI reed switch: Provides greater durability and long term reliability compared with thick-film swim arm style senders so users see fewer failures over time.
• 240-33 ohm output: Matches American standard gauges with 240 ohms at empty and 33 ohms at full for straightforward compatibility with common fuel gauges.
• 316 stainless steel construction: Heavy duty, corrosion resistant housing and mounting pattern make it suitable for marine environments and long service life.
• Complete installation kit: Ships with gasket, mounting screws and illustrated instructions which simplifies installation for DIYers and techs alike.
• Float size and fit guidance: The float is 1.38in diameter and suggested hole if drilling is 1.50in, helping installers plan mounting accurately.
• 1 year limited warranty: Backed by free lifetime technical support to assist with fitment and troubleshooting after purchase.

Who It's For

This sender is aimed at boat owners, RV and truck owners, and fleet technicians who need a durable replacement for an arm type fuel sender and prefer a product with minimal moving parts. It is especially good for sailboats and larger fuel tanks where customers reported accurate readings and a clean fit.

Those who should look elsewhere include users requiring a nonstandard sender length outside the 4in to 32in range without contacting the maker, or those who need digital, multi-sensor telemetry features that this mechanical-electrical sender does not provide.

Pros & Cons

Pros

• Solid build quality with heli-arc style welding and 316 stainless steel for corrosion resistance.
• Reliable OKI reed switch mechanism with no delicate moving electronics to adjust or replace.
• Easy installation: comes with gasket, screws and clear wiring instructions that multiple customers praised.
• Accurate readings and good fit for common tank sizes, reported to work well on 50 gallon tanks.

Cons

• Only available in standard lengths from 4in to 32in without custom ordering, which may not suit every tank depth.
• Float diameter and mounting require drilling a 1.50in hole if no existing access exists.

Specifications

Our Verdict

The 100TECH 240-33 ohm fuel sending unit is a practical, well built direct replacement for arm type senders and offers excellent value for owners who need a dependable marine or vehicle fuel sender. Its reed switch design and 316 stainless construction reduce failure points and the included hardware and clear instructions make installation straightforward, so it is a smart buy for DIYers and professionals who want a durable, accurately reading unit.

Frequently Asked Questions

Will this work with my 240-33 ohm gauge?
Yes, it uses the American standard 240 ohm at empty and 33 ohm at full output to match 240-33 ohm gauges.

Can I get a different length than 13in?
Standard lengths range from 4in to 32in; contact the seller directly for other length options.

Do I need to adjust the sender for my tank?
No adjustment is needed for the tank, but measure tank depth from the top and subtract 1in to avoid the sender hitting the bottom.