Bentolin Generator Accessories Portable Oil Change Funnel fits for Yamaha Ef2000iSv2 EF2200iS Wen Generator 56200i 56203i 56235i Westinghouse WH2200iXLT Generac 7117 GP2200i Rainier R2200i

What this tool is and why I wanted it

Small inverter generators are brilliant until you need to change their oil. The fill/drain ports are tucked inside cramped panels, the drain angle is awkward, and even with rags and a shallow pan, it’s easy to make a mess. The Bentolin generator oil-change funnel tackles that problem with a simple idea: instead of balancing a traditional funnel near a dark, recessed opening, you thread a flexible, clear spout directly into the generator’s oil fill port and guide the oil—out or in—exactly where you want it. No juggling. No guessing.

I maintain a few compact units for camping and backup power, and a clean, quick oil change is the difference between a 10-minute chore and an hour of cleanup. That’s why I put this funnel in my kit.

Setup and first impressions

The funnel is basically a short, rigid threaded collar bonded to clear, flexible tubing. It’s light, compact, and coils into a pocket in my generator bag without kinking. The transparency is more useful than it looks—watching the oil darken as it drains, and seeing bubbles clear when filling, takes the guesswork out of the process.

The threading is the whole trick here. On the generators that matched, the collar caught cleanly and sealed well with just hand-tight pressure. On my Predator 2000 inverter and an EcoFlow Smart Generator, it threaded on smoothly, seated snug, and didn’t dribble around the collar. The fit is tight enough that I felt comfortable moving the tube without supporting the collar.

A note on heat: it’s still plastic. I let the generator cool to “warm” before draining; very hot oil can soften flexible tubing on any funnel of this style. With warm (not hot) oil, the tube stayed shape-stable and clear.

In use: draining and refilling without the mess

• Draining: With the funnel screwed in, I routed the tube into an oil pan and cracked the fill cap to vent. The oil started flowing at a controlled pace. Because the tube is flexible, I could “aim” around the frame and away from rubber feet or the muffler. On the Predator, I didn’t need to lift or tip the unit until the very end—only a slight tilt helped coax the last tablespoon out. The clear tubing made it obvious when the flow tapered off.

• Refilling: I kept the funnel installed, brought a measured amount of fresh oil in a squeeze bottle, and fed it slowly. You see the oil rise in the tube, and you can pause instantly if anything backs up. No burps, no splash-back. I prefer this to trying to balance a mini-funnel in a dark fill hole while pouring from a quart.

• Cleanup: I let the remaining oil drip through, wiped the collar with a rag, and ran a quick stream of isopropyl alcohol through the tube. It cleared residue well and cut the smell. After air-drying, the tube stayed clear and pliable.

Overall, the process felt controlled and unrushed. Even on a windy day outside, I didn’t fight stray drips or dust settling into an open funnel.

Build quality and durability

For such a simple tool, failure points matter. The collar threads on my unit were cleanly molded with no flashing, and the bond between the collar and tube felt solid—no wiggle, no seepage. The tubing wall is thin enough to be flexible yet stiff enough to hold a gentle curve. I wouldn’t leave it in contact with a hot engine block, but normal drape and routing were fine.

After several changes, the tube remained clear (no yellowing yet), and the collar threads didn’t round off. This is still a plastic-on-metal interface—hand-tight is the rule. I didn’t need pliers, and I wouldn’t use them even if tempted. Cross-threading is possible if you rush; I found starting the collar squarely and backing off a quarter turn before threading in helps it seat smoothly.

Fit and compatibility notes

This style of threaded funnel lives or dies by matching your generator’s oil fill threads. The funnel worked perfectly on:
- Predator 2000 inverter
- EcoFlow Smart Generator (Dual Fuel) and Smart Generator 4000

It also fit a friend’s WEN 56200i without drama. On another compact inverter labeled DuroMax 2000, the collar wouldn’t catch—the threads were just a hair off. That mismatch confirmed the reality here: different brands (and even different model lines) use different thread sizes and pitches on the oil fill tube.

Two practical takeaways:
- Don’t force it. If you don’t feel the threads catch within the first half-turn, back out and try again. Forcing will chew the collar.
- Verify compatibility before you depend on it. If you’re buying specifically for a generator not listed by the maker, bring your old dipstick/fill plug to a shop and compare threads, or check with support. If you have a thread gauge or calipers, measure your fill plug—many small inverters use metric threads, but they’re not standardized across all brands.

How it compares to traditional funnels

I’ve used low-profile aluminum funnels, generic plastic funnels with vinyl tubing, and even DIY adapters. Each has trade-offs:

• Traditional funnels are cheap and heat-resistant, but they’re hard to position inside cramped service panels and can splash as you pour.
• Vinyl-tube hacks reach well but don’t seal, so oil can creep around the fill hole and onto the case.
• Threaded aluminum adapters are excellent but usually model-specific and much more expensive.

The Bentolin funnel hits a sweet spot: it’s not as bombproof as a machined adapter, but it’s far easier and cleaner than a traditional funnel, and it’s more adaptable than a rigid solution. The screw-in seal is what makes it worthwhile.

Speed, cleanliness, and control

• Flow rate: Controlled. The internal diameter is narrow enough to prevent gushing. Draining takes a couple of minutes vs. a quick dump, which I prefer when I’m avoiding splatter.
• Spill control: Excellent. The only drops I saw were from the last bit in the tube when removing the collar—easily caught with a rag.
• Precision: The clear tube helps aim and visually confirm both draining and filling. Small touch, big difference.

Maintenance and storage

I treat it like any oil-contact tool:
- Rinse the tube with a splash of isopropyl alcohol after each use to reduce odor and keep the plastic clear.
- Hang it or coil it loosely so it doesn’t kink at the collar.
- Keep it out of direct sun in a hot vehicle; extended heat can age flexible tubing prematurely.

Avoid harsh solvents like brake cleaner on the tube; they can cloud or embrittle plastic.

Limitations and small misses

• No thread spec provided. The collar works on many popular inverters, but the lack of a published size/pitch makes pre-checking harder than it should be.
• Heat sensitivity. It’s fine for warm oil, but if you try to drain right after shutdown, you’re flirting with softening the tube. Give it a few minutes.
• Not universal. If you maintain a mixed fleet, expect that one unit may not fit. It’s worth owning, but not the only solution you’ll ever need.

Who it’s for

• Owners of compact inverter generators who change oil in the field or in tight spaces.
• DIYers who value a clean, controlled process more than shaving 30 seconds off the drain time.
• Anyone who’s tired of balancing mini-funnels and wiping down oily frames.

If you service larger open-frame generators with easy-access drains, this is less critical. But for the small inverters many of us actually carry, it’s a quality-of-life upgrade.

Value

It’s essentially a threaded collar with a tube, so it can feel pricey for plastic. But oil on sound-deadening foam, recoil housings, or rubber feet is a pain to clean and can attract dust that never quite goes away. After a few oil changes, the time and frustration saved justified the cost for me. I’d rather spend a bit more once than wrestle with drips every time.

Tips for best results

• Let the engine cool to warm—safe to touch—before draining.
• Start the thread gently; if it doesn’t catch smoothly, reset and square it up.
• Crack the fill cap/dipstick to vent while draining to keep flow steady.
• Pre-measure your refill volume and go slow; the clear tube will show when the crankcase is close to full.
• Keep a rag under the collar when you remove it to catch the last drop.

Recommendation

I recommend the Bentolin oil-change funnel for anyone maintaining small inverter generators, especially Predator, EcoFlow, and WEN units similar to those I tested. It turns a cramped, messy chore into a controlled, spill-free process. The flexible, transparent tube and threaded seal are the right design choices, and the lightweight form factor makes it easy to keep in a service kit.

I’d like to see the manufacturer publish the exact thread size and pitch, and it’s not the tool to use on a scorching-hot engine. But if your generator’s fill port matches, this is a simple, effective upgrade that pays for itself in cleaner, faster oil changes.