100TECH Fuel Sending Unit 240-33 ohms 11in - Durable Reed Switch

In this review the 100TECH Fuel Sending Unit is evaluated for boat and vehicle owners who need a reliable replacement sender without fuss. The bottom line: it is best for users who want a rugged, low-maintenance sensor that reads with American standard 240-33 ohms output and resists common failure modes. The reviewer found the stainless steel construction and OKI reed switch make this unit notably durable, and the simple installation and direct-replacement fit are the most convincing reasons to consider it for marine and automotive tanks.

Key Features

• Reed switch construction: Uses an OKI reed switch imported from Japan which delivers greater durability and reliability than thick-film swim arm type senders.
• Standard output: Provides American standard 240-33 ohm output so it matches most fuel gauges calibrated to that range without modification.
• Stainless steel build: Heavy duty 316 stainless steel and rugged construction resist corrosion in marine and automotive environments.
• Easy installation: Ships with gasket, mounting screws and illustrated instructions so wiring and mounting are straightforward for DIYers.
• SAE 5-hole mounting: Fits common 5-hole mounting patterns for direct replacement in many boats, trucks and RVs.
• Compact float: A 1.38in (35mm) diameter float designed to work in tanks where a 1.50in (38mm) hole is available if drilling is required.

Who It's For

This sender is aimed at boat owners, RV and truck owners, and mechanics who need a robust replacement for an arm type fuel sender and prefer a unit with no moving electrical parts to adjust. It is particularly useful in marine environments where corrosion resistance and durable joints are important.

It is less suitable for systems that require nonstandard resistance curves or proprietary electronics, and customers needing custom lengths outside the 4in-32in range should contact the manufacturer rather than expecting a different length out of the box.

Pros & Cons

Pros

• Sturdy 316 stainless steel body and heli-arc style welded joints reported by users give long-term durability.
• Reliable OKI reed switch eliminates fragile thick-film parts, reducing failures.
• Straightforward installation with gasket and screws makes replacement quick for DIYers.
• Accurate readings and good fit reported for common tank sizes such as 50 gallon tanks.

Cons

• Limited to the American standard 240-33 ohm output curve, so systems with different calibration may need adaptation.
• Lengths outside the 4in-32in range are not standard and require contacting the seller for options.

Specifications

Brand	100TECH
Output	240-33 ohms (240 empty, 33 full)
Length options	Standard lengths 4in to 32in
Float diameter	1.38in (35mm); hole approx 1.50in (38mm)
Mounting	SAE 5-hole mounting pattern
Construction	316 stainless steel, rugged construction

Our Verdict

The 100TECH Fuel Sending Unit is a practical, value-oriented replacement for arm type senders where durability and low maintenance matter. Its OKI reed switch and stainless steel build make it a smart pick for boats, trucks and RVs that accept the 240-33 ohm curve, and the included hardware simplifies installation. For anyone looking for a long-lasting, accurate sender that fits common mounting patterns, this unit represents good value.

Frequently Asked Questions

Does it fit standard fuel gauges?
Yes, it uses the American standard 240-33 ohm output so it is compatible with gauges expecting that range.

What mounting pattern does it use?
It uses an SAE 5-hole mounting pattern and ships with gasket and mounting screws for direct replacement.

Can I get other lengths?
Standard lengths cover 4in to 32in; contact the seller directly if you need a length outside that range.