Fuel Sending Unit 13.5in Boat Fuel Level Sensor - Durable Reed Switch

In this review of the 13.5in fuel sending unit, the bottom line is simple: this sender is aimed at boat and vehicle owners who need a rugged, direct-replacement fuel or water level sender that reads reliably over time. The reviewer found the biggest reason to buy is the OKI reed switch core and stainless steel construction, which deliver durability and steadier readings compared with swim arm style senders. Installation is straightforward and the unit ships with the gasket and screws needed to fit common SAE 5-hole mounts.

Key Features

• OKI reed switch: Imported reed-switch sensing provides more durable switching action than thick-film swim arm types, improving long-term reliability.
• Stainless steel construction: Corrosion-resistant body and hardware help the sender withstand marine environments and road use.
• SAE 5-hole mounting: Direct replacement for many OEM arm-type senders, so it fits common boat and vehicle tank flanges without modification.
• Complete kit: Ships with a cork gasket, five mounting screws and illustrated instructions to make installation fast and minimize exposure to fuel fumes.
• Wide fluid compatibility: Suitable for diesel, gasoline and water tanks, allowing use as either a fuel level or water level gauge sender.
• 240-33 ohm output: Provides a standard non-linear signal (240 ohm at empty, 33 ohm at full) compatible with many gauges.

Who It's For

This sender is best for boat owners, RV and truck owners, and DIYers replacing an arm-type OEM sender who value robustness and an easy swap-in fit. It particularly suits installations where a stainless body and a reed switch are preferred over film or swim arm types for longevity.

Those who should look elsewhere include users who need a very short or extremely long sender length outside the available 4in to 24in range or systems requiring a linear output different from the 240-33 ohm curve; contact the seller for custom lengths if needed.

Pros & Cons

Pros

• Durable OKI reed switch offers reliable switching and better longevity than thick-film senders.
• Solid stainless steel construction and quality welds noted by customers for good build quality.
• Includes gasket, screws and clear instructions, making a typical install under 15 minutes.
• Works with diesel, gasoline and water, providing flexible application across boats and vehicles.

Cons

• Non-linear 240-33 ohm output may not match every gauge without verification or calibration.
• Float diameter and sender length require measuring the tank carefully to avoid interference with tank bottom.

Specifications

Brand	100TECH
Length	13.5in (343mm)
Signal output	240-33 ohm (240 empty, 33 full)
Mounting pattern	SAE 5-hole
Materials	Stainless steel construction
Included items	Cork gasket, 5 mounting screws, instructions
Float diameter	1.38in (35mm)

Our Verdict

The 13.5in 100TECH fuel sending unit is a practical, value-oriented replacement for arm-type senders where durability matters. With an OKI reed switch, stainless body and included gasket and screws, it is a smart choice for boat and vehicle owners who want a reliable, easy install and broad fluid compatibility without overspending.

Frequently Asked Questions

Will this fit my existing SAE 5-hole flange?
Yes, it uses the SAE 5-hole mounting pattern and is intended as a direct replacement for common arm-type senders.

What is the electrical output curve?
The sender reports a non-linear resistance from 240 ohm at empty down to 33 ohm at full.

Does the package include install hardware?
Yes, it includes a cork gasket, five mounting screws and illustrated instructions for installation.