100TECH Marine Fuel Sending Unit Float Replacement 17in - Durable Reed

In this review of the 100TECH 17in fuel sending unit, the bottom line is simple: this is a practical, heavy duty replacement for owners who need a reliable tank level sender for boats, RVs or vehicles. The unit's biggest selling point is its reed switch design made with OKI components from Japan, which eliminates the fragile moving parts found on conventional swim arm senders. Installation is straightforward and the gauge output uses the American standard 240-33 ohms, making it a direct swap for many existing gauges.

Key Features

• OKI Reed Switch: Uses an imported reed switch for greater durability and reliability compared with thick-film swim arm type senders.
• 240-33 ohm Output: American standard resistance range allows direct compatibility with most fuel and water gauges without recalibration.
• 316 Stainless Steel Construction: Heavy duty materials and rugged construction resist corrosion in marine environments.
• Easy to Install: Ships with a gasket, mounting screws and clear illustrated instructions to simplify replacement in existing SAE 5 hole patterns.
• Float Size and Fit Guidance: 1.38in float diameter and recommended 1.50in hole if drilling, helping installers plan tank access accurately.
• Support and Warranty: Backed by a 1 year limited warranty and free lifetime technical support for troubleshooting and fit questions.

Who It's For

This sending unit is best for boat owners, RV enthusiasts and vehicle owners replacing an arm type sender who want a durable, low-maintenance sensor. It is particularly suited to marine environments where stainless steel and reed switch reliability matter, and for users who need the American standard 240-33 ohm output for direct gauge compatibility.

It is less appropriate for someone who needs a custom length outside the offered range without contacting the seller, or for installations where the float could contact internal tank fittings or the bottom without modifying tank depth; the product instructions advise measuring from the top of the tank and subtracting 1 inch to prevent bottom hits.

Pros & Cons

Pros

• Durable OKI reed switch design reduces moving parts that typically fail in swim arm senders.
• Solid 316 stainless steel construction and SAE 5 hole mounting for reliable marine use.
• Easy installation with gasket, screws and clear wiring instructions accepted by customers as straightforward.
• Accurate, repeatable 240-33 ohm output praised for good fit and accuracy on common tank sizes.

Cons

• Length options are limited to standard sizes; customers needing nonstandard lengths must contact the seller.
• The float diameter requires a 1.50in hole if drilling, which may need additional tank modification on some installs.

Specifications

Brand	100TECH
Length	17in (430mm)
Output Resistance	240-33 ohms (240 empty, 33 full)
Float Diameter	1.38in (35mm)
Recommended Hole if Drilling	1.50in (38mm)
Mounting Pattern	SAE 5 hole
Material	316 stainless steel

Our Verdict

The 100TECH 17in fuel sending unit is a smart, value-oriented replacement for anyone swapping an arm type sender in a boat, RV or vehicle. Its OKI reed switch and 316 stainless steel build deliver dependable operation and fewer failures, while the standard 240-33 ohm output ensures gauge compatibility. For installers willing to verify tank depth and fit, this unit offers reliable readings, solid build quality and good support, making it a practical buy for routine replacements.

Frequently Asked Questions

Will this work with my 240-33 ohm gauge?
Yes, the sender uses the American standard 240-33 ohm output and is designed to be directly compatible with gauges using that range.

Can I cut the sender to a shorter length?
The listing notes standard lengths; contact the seller for custom lengths rather than cutting, to preserve calibration and warranty.

What size hole do I need if I must drill?
If drilling a new access point, a 1.50in (38mm) hole is recommended to accommodate the float and mount.