Fuel Gauge Sending Unit 240-33 ohms 7ft - Durable Reed Switch Sender

In this review the 100TECH Fuel Gauge Sending Unit is examined for boat, RV and truck owners who need a reliable replacement for an arm type sender. The bottom line: this sender is worth considering when durability and simple, accurate readings matter most. Built with an OKI reed switch imported from Japan and heavy duty 316 stainless steel, it aims to remove fragile moving parts and frequent adjustments that plague thick-film swim arm senders. Installation is straightforward and the unit delivers the expected American standard 240-33 ohm output for common gauges.

Key Features

• OKI reed switch: Provides improved durability and reliability compared with thick-film swim arm designs, reducing failure points.
• 240-33 ohm output: Matches American standard gauges so it reads 240 ohms at empty and 33 ohms at full, simplifying replacement.
• 316 stainless construction: Heavy duty, rugged build resists corrosion in marine and automotive environments for longer service life.
• Easy to install: Ships with gasket, mounting screws and illustrated instructions so most owners can fit it without specialist tools.
• SAE 5-hole mount: Common mounting pattern fits many tanks and reduces the need for tank modification when replacing an arm type sender.
• Clear float sizing: Float diameter of 1.38in and recommended hole size of 1.50in helps plan installation and avoids surprises when drilling.

Who It's For

This sender is aimed at boat owners, RVers and truck owners who want a durable, low-maintenance replacement for a traditional arm type fuel or water level sender. It is particularly suitable for those who value robust construction and prefer a sender with no moving electrical parts to fail, and for installers who want standard 240-33 ohm compatibility.

Those who should look elsewhere include owners needing nonstandard probe lengths not listed in the base product or users with extremely shallow tanks where the float clearance recommendation cannot be met. If you need a custom length, the manufacturer asks that you contact them directly before buying.

Pros & Cons

Pros

• Durable reed switch design offers better longevity than thick-film swim arm senders.
• Solid 316 stainless steel construction and good build quality reported by users.
• Easy installation with gasket, screws and clear wiring instructions included.
• Accurate, consistent 240-33 ohm output that fits many standard gauges.

Cons

• Limited to listed lengths unless you contact the seller for alternatives, which may delay fitting to unusual tanks.
• Float and sender length require measuring tank depth carefully to avoid bottom contact; users must subtract 1in from tank depth.

Specifications

Brand	100TECH
Output	240-33 ohms (240 empty, 33 full)
Length	7in (180mm) available; other lengths 4in-32in on request
Material	316 stainless steel
Mounting	SAE 5-hole pattern
Float diameter	1.38in (35mm); drill hole 1.50in suggested
Warranty	1 year limited warranty and free lifetime technical support

Our Verdict

The 100TECH Fuel Gauge Sending Unit is a practical, cost-effective replacement for owners who need a tough, low-maintenance sender that works with standard 240-33 ohm gauges. Its reed switch and 316 stainless construction make it a strong choice for marine and automotive use, and straightforward installation plus good customer feedback on fit and accuracy make it good value for most users who fit the sizing guidance.

Frequently Asked Questions

Will this work with my standard gauge?
Yes. The sender provides the American standard 240-33 ohm output, which matches most standard fuel level gauges.

Do I need to adjust the sender inside the tank?
No. The reed switch design requires no tank adjustment; follow the instruction to measure tank depth and subtract 1in to avoid the float hitting the bottom.

What if I need a different length?
Other lengths between 4in and 32in can be requested; contact the seller directly for custom lengths and compatibility advice.