Marine Fuel Tank Cap with Mechanical Gauge
Aftermarket replacement fuel tank cap with integrated mechanical float gauge and manual vent.
This model is designed primarily for Easterner portable marine fuel tanks using the matching thread and sender dimensions.
Important compatibility information:
This cap is a direct fit for compatible Easterner tanks. It may also fit some Yamaha, Honda, Mercury, Mariner, Suzuki and Tohatsu portable tanks,
but OEM tanks can use slightly different thread profiles even when the diameter appears similar.
Fitment must therefore be confirmed by measurement before ordering.
Do not rely only on tank capacity, colour, appearance or outboard brand. A 12L, 24L or 25L tank from a different manufacturer may use a different thread,
sealing face or sender depth.
Measured Specifications
| Approximate thread diameter |
55 mm |
| Sender length |
170 mm |
| Gauge type |
Mechanical float gauge |
| Vent |
Manual screw vent |
| 4Boats SKU |
mms-4114 |
Compatibility
-
Easterner portable fuel tanks: intended application where thread and sender dimensions match.
-
Yamaha genuine tanks: may fit some tanks, but the thread can be slightly different and may feel unusually tight.
-
Honda, Mercury, Mariner, Suzuki and Tohatsu tanks: some applications may be compatible, but fitment is not universal.
A cap that looks visually identical may still use a different thread pitch or sealing arrangement.
If your original tank is an OEM Yamaha, Honda, Mercury, Suzuki or other branded tank, we strongly recommend comparing the measurements before ordering.
How to Check Before Ordering
- Remove your existing cap.
- Measure the approximate outside diameter of the threaded tank neck or corresponding cap thread.
- Compare this measurement with the approximate 55 mm diameter of this cap.
- Measure the sender depth from the underside of the sealing surface to the end of the float mechanism.
- Confirm that the 170 mm sender has sufficient clearance inside your tank.
- Compare the thread profile, sealing gasket and overall cap shape with the product photographs.
Not sure?
Send 4Boats a clear photo of your fuel tank, filler neck and original cap together with a ruler or calliper measurement.
We will help you check compatibility before ordering.
Fitting Advice
The cap should engage smoothly and screw down squarely onto the tank neck.
- Do not force the cap if it feels cross-threaded.
- A slightly tighter fit may occur on some OEM tanks because the thread profile is not identical.
- Once fitted, make sure the gasket seats correctly.
- Check carefully for any fuel or vapour leakage before using the tank.
If the cap screws on securely, seals correctly and does not leak, it may be usable even where the thread feels slightly tighter than the original.
However, if the thread does not engage properly or the cap cannot be fully seated, do not use it.
Use and Safety
- Inspect the cap, gasket, float mechanism and vent before each use.
- Check for fuel or vapour leakage immediately after installation.
- Never use a cap that is cross-threaded or does not seal correctly.
- Ensure the float mechanism moves freely inside the tank.
- Operate the manual vent according to the tank and outboard manufacturer's instructions.
Frequently Asked Questions
Is this a genuine Yamaha, Honda, Mercury or Suzuki part?
No. This is an aftermarket replacement part.
What tanks is it designed for?
It is designed primarily for compatible Easterner portable marine fuel tanks using the corresponding approximately 55 mm thread and 170 mm sender.
Will it fit a genuine Yamaha fuel tank?
Possibly, depending on the tank version. Some genuine Yamaha tanks use a very similar but not identical thread, which can make this cap noticeably tighter.
Measurements should be checked before ordering.
Does it fit every 12L or 25L portable tank?
No. Tank capacity alone does not determine compatibility.
What if the cap feels tight?
Make sure it is starting squarely and is not cross-threaded. Do not force it.
If it screws down correctly and seals without fuel or vapour leakage, the fit may still be acceptable.
What if I need the exact OEM fit?
For genuine Yamaha or other OEM tanks, the safest option is the manufacturer's genuine gauge assembly matched to the exact tank model.
Genuine gauges can be significantly more expensive than aftermarket replacements.
