You might think that a full restoration of an engine left idle for a long time is impossible to do without a professional mechanic. It could be a lawnmower or seasonal equipment such as snow blowers. Idle cars can stall from stale gas and an accumulation of water in the tank.

Mechanic in a Bottle works with all of these machines and is formulated to start things up in as little as four hours, sometimes quicker. Shown below are various sizes of the product, each of them containing the same trusted formula but suited for different purposes according to size and quantity. Let’s take a closer look.

Comparison Table

B3C Fuel Solutions 2-004-12
Size: 4 oz

Quantity: 1 Bottle

2 and 4-Stroke Safe: Yes

B3C Fuel Solutions 337129
Size: 4 oz

Quantity: 1 Bottle

2 and 4-Stroke Safe: Yes

B3C Fuel Solutions 2-008-9
Size: 8 oz

Quantity: 1 Bottle

2 and 4-Stroke Safe: Yes

Rotary Corp
Size: 128 oz

Quantity: 1 Bottle

2 and 4-Stroke Safe: Yes

B3C Fuel Solutions 2-008-9 9
Size: 8 oz

Quantity: 9 Bottle

2 and 4-Stroke Safe: Yes

B3C Fuel Solutions 2-004
Size: 4 oz

Quantity: 1 Bottle

2 and 4-Stroke Safe: Yes

B3C Fuel Solutions 2-018-6
Size: 18 oz

Quantity: 1 Bottle

2 and 4-Stroke Safe: Yes

B3C Fuel Solutions 2004D
Size: 4 oz

Quantity: 1 Bottle

2 and 4-Stroke Safe: Yes

B3C Fuel Solutions 4
Size: 4 oz

Quantity: 1 Bottle

2 and 4-Stroke Safe: Yes

Top 9 Best Mechanic In A Bottle

Mechanic in a Bottle 2-004-12 Gas Treatment – Best for Small Tanks

Mechanic in a Bottle 2-004-12 Gas Treatment - Best for Small Tanks

Mechanic in a Bottle prides itself on fast improvements to machinery and motor vehicles. The 2-004-12 is a four-ounce bottle from the company that’s easy to pour. Add it to your two or four-cycle engines of any variety.

This includes lawn mowers, blowers, chainsaws, and any old vehicles you have lying in your garage. The formula works rapidly and is safe for carburetor use. Don’t worry about removing the entirety of your carburetor from the engine to do this. Just take off the bowl and add, or the fuel tank.

How to Best Use the Product

If you flush with the 2-004-12, it’s a good idea to wait for a couple of hours, more depending on how old the machine has been idle. For use on motors used in the last season, a startup might occur in 15 minutes. You can pour as much as you want, though the recommended amount is one ounce for every gallon.

To clarify, if your tank holds three gallons of fuel, use three ounces at the least. But going over this amount is perfectly fine and won’t cause damage to the engine at all.

The specific bottle has a cap that’s difficult to keep closed unless it’s tightly done. When you’re ready to open it back up again, getting it to budge might prove difficult. store the bottle in a cool place that stays within room temperature more often than not and this issue shouldn’t happen. Give the 2-004-12 a run in your tank, especially if there’s just one machine giving your trouble.

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  • Works well on two and four-cycle engines
  • Can power up a faulty lawnmower in as little as 15 minutes
  • No limitation on how much should be used
  • The bottle cap is loose and must be tightly closed to prevent leakage

Maxpower 337129 – Best for Old Machinery

Maxpower 337129 - Best for Old Machinery

The Maxpower 337129 is another 4-ounce bottle with a quantity of one. You can use it for treating your car’s engine by placing a little in the fuel line. If you prefer, add the entire bottle to the mix and let the formula do the rest. Mechanic in a Bottle doesn’t necessitate that you empty the tank before you pour it. If your gas is old and stale, the liquid will rejuvenate it and allow the engine to run again. At the same time, the accumulation of rust and drying will be prevented.

Flushing Out the Tank

Consider doing the flush for vehicles left idle for longer than a year. Take out the fuel, add the formula, then let it sit for at least 24 hours before adding more fuel. Your engine will run again at the first turn of the ignition. On motorbikes, this process can be done faster, typically in a few hours. Motorcycles are no different. You might need an additional bottle on top of just one. Add it to your glove compartment and have it ready when you need it.

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  • Works with old gas left in the tank
  • Can be placed in a carburetor bowl or gas tank
  • Works on vehicles and motorbikes
  • Cleaning out seldom used engines will be an overnight process to complete

Ethanol Fuel Treatment – Best for Stationary Machinery

Ethanol Fuel Treatment - Best for Stationary Machinery

Mechanic in a bottle also works as an ethanol treatment for your fuel. As is listed on the bottle, you can keep existing fuel healthy in your tank when you’re not using it, lowering the chances of what’s inside going bad again. Ethanol tanks of all kinds are safe here, including generators and your home lawn equipment.

Used in a Generator

Generators are something that’s used in emergencies, or for camping. It’s recommended that you have an 8-ounce bottle in storage alongside the generator, especially if you use it infrequently. Doing so guarantees that it’ll crank up fast when you need it to, and keep whatever gas you had left since the last startup remains usable in the future.

Take notice that only one ounce is suggested here as well, giving you more formula to have around for other restoration jobs you come across. But for generators, this 8-ounce tube is more than enough to keep your RV or home powered when the electricity goes down.

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  • Safe to place in ethanol tanks
  • Good product to have around for as an accessory for old generators
  • For most engines, 1 ounce should be enough for every gallon of gas
  • Will not work to fix waterlogged carburetors and tanks unless completely drained

Mechanic in A Bottle 128 oz – Best for Flushing

Mechanic in A Bottle 128 oz - Best for Flushing

The Rotary Corp Mechanic in a Bottle is one of the largest varieties sold by B3C. Its 128 ounces are great for people who work with vehicles, trucks, or landscaping equipment. Keep all of your machines operating as they should, no matter if they’re infrequently use by you or not. 128 ounces is a gallon. Don’t put it all into the tank on the first go.

However, older engines will definitely need more than younger ones. During flushing, it can clean out your tank from an unwanted buildup of sediment and restore the carburetor from causing the engine to run with low torque.

Getting the Right Size

This is a gallon-sized jug for lots of lawn tools. It’ll keep you from having to buy more when you need it. The average Mechanic in a Bottle’s size is four ounces so it’s likely that this version will last you for a long time if there isn’t much for you to use it on.

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  • Size is suggested for large engines such as cars and some motorcycles
  • Great for people with numerous lawn tools and other fuel-dependent machinery
  • Breaks down stale fuel in tanks
  • It may take longer for effects to be seen, particularly with big engines

B3C Fuel Solutions 2-008-9 – Best for Multiple Tanks

B3C Fuel Solutions 2-008-9 - Best for Multiple Tanks

2-008-9 is the serial number for Mechanic in a Bottle’s eight-ounce cases. But this is sold as a bundle of nine bottles. That’s 72 ounces in all, with their own separate containers. Here are the advantages:

The first is quantity. Give them out as a gift to your friends, or place them on the shelf for when you need them later. Uncapping this lid is easy, and the pour is quick. The reduced size of the bottle’s tip is great for adding to very small engines such as those commonly found on chainsaws, weeders, and trimmers.

In a car, you could use them too but it may take more than one bottle to see the results that you want. If you add to the bowl of a carburetor during a flush, you can use the same batch of liquid again in the fuel tank. Doing this will save you the trouble of having to open up another bottle.

Using the Bottles Effectively

These bottles are small, which means the lettering might be harder for you to see if your vision is imperfect. To stop yourself from squinting, add one ounce for every gallon or more as needed. Your engine will turn on a short moment later and perform as it did during the last time you turned it on.

This set of nine is great as a gift idea for people that prefer a larger quantity, but don’t feel the need to buy a gallon-sized bottle to do the job.

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  • Smaller bottle size makes for easier storage when the product isn’t being used
  • Doesn’t create rust but instead cleans it out
  • In some cases, the liquid passing through carburetors is reusable
  • Instructions are difficult to read on the label

B3C Fuel Gas Treatment – Best for Seasonal Equipment

B3C Fuel Gas Treatment - Best for Seasonal Equipment

The B3C Fuel Gas Treatment is a four once Mechanic in a Bottle that’s highly recommended as an emergency kit for your vehicle. This product isn’t only useful for starting up old engines. You can use it to keep the current state of your running vehicle or motor equipment in good condition. It has a high rate of effectiveness when measuring out the proper amount of your car.

No Risk of Using Too Much

The worry isn’t you going over, but under. Remember, Mechanic in a Bottle is safe for you to add more than what’s required. In other uses, the four-once bottle works on snowblowers well, new and old. Getting an old snowblower to work is tricky when it hasn’t been done in a long time.

Don’t take out the carburetor or ethanol if you don’t want to, it’ll clean when it’s added to the tank’s nozzle. Put it in a place where you won’t lose it, though. The 4-ounce size is smaller than it appears in photos.

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  • The 4-ounce bottle easily fits into vehicle emergency kits
  • Has a high rate of success as long as the instructions are followed
  • Safe for snowblowers
  • Unless put away in a designated location, the bottle’s size makes it easy to lose

B3c Fuel Solutions 2-018-6AM – Best for Unserviced Vehicles

B3c Fuel Solutions 2-018-6AM - Best for Unserviced Vehicles

This is the 18-ounce bottle of B3C’s famed product. The formula is the same as the others, only the quantity is different. So why should you consider this one before the others?

First, there’s less to worry about losing here. You may want a bottle to keep around for later use, not something that you’ll add to a tank immediately. Most lawn mowers and other small motor equipment have tanks that are less than 10 gallons, requiring less than ten ounces to pour into your engine. Don’t be afraid to add more than this when the engine is very old.

Cleaning up the Mess

Water and sediment may have developed around the gaskets, tanks, and smaller engine parts. In cars, you can look forward to your motor vehicle’s engine running great, boosting its horsepower and fuel efficiency. It doesn’t take long for this to happen. Let the liquid remain in your car for about a day in this situation and that’s it.

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  • Ideal for vehicles that haven’t undergone servicing in a long time
  • Takes out the moisture from a tank and prevents it from coming back
  • Boosts fuel efficiency and horsepower
  • Small label

B3C Fuel Solutions 2004D – Best Travel-Sized Container

B3C Fuel Solutions 2004D - Best Travel-Sized Container

Don’t be alarmed by the warning on the labeling of this four-ounce tube from B3C. Use it according to the instructions and you’ll do so in a safe manner. And you’ll want to have this around, more if loud engines are a problem for you. There are fewer things more headache-inducing than a loud engine on a car or lawn equipment. A lot of the noise could come from the carburetor or tank from a lack of lubrication on the inside.

Good When Away From Home

One would normally think that the fuel in such a scenario would be useless, but not with Mechanic in a Bottle. This is based on the route that you take and if the tank inside won’t be completely flushed.

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  • Reduces annoyingly loud engines and carburetors within minutes of adding to the tank or bowl
  • Makes old fuel reusable again if flushing isn’t preferred
  • Travel-friendly size
  • A 24-hour waiting period might be necessary before improvement to the engine are noticed

B3cfuel Solutions Inc – Best for Small Engines

B3cfuel Solutions Inc - Best for Small Engines

This B3C is four ounces and good for anyone that can’t or won’t visit a vehicle repair shop but is having engine trouble. For tanks with a considerable amount of moisture inside, loud noises may emit from the carburetor. This is fixed with Mechanic in a Bottle, the formula evaporating any water that it comes across on the inside.

Use in Old Fuel

The remaining fuel you have will power your machinery until it’s time for more and will work like new from this moment on. Try a larger container if you’re working on a car engine, or if you have a couple of fuel-powered tools laying around for a while.

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  • Level meters on the bottle help to prevent the user from pouring too much
  • Pours quickly and doesn’t stick to the inside of the bottle, even in cool weather
  • Staves off an expensive vehicle or motor repair
  • More than one bottle might be needed for larger engines

Buyer’s Guide

How does Mechanic in a Bottle Work?

Mechanic in a Bottle works by lubricating the interior parts of your vehicle’s tank, engine, and carburetor, steadily breaking down settled fuel, then adding strength to any existing gaskets or other plastic parts. When a car or other piece of machinery hasn’t been turned on in a long time, these issues are imminent. However, this formula is proven to work, and very fast. It’s safe for two and four-cycle engines of all kinds.

Why Should it be Used?

Flushing out an engine is tedious work that can take time. And even when this is done, that doesn’t guarantee it’ll turn on. To ensure that your work won’t be in vain, it’s recommended that you buy something to prevent what’s causing your engine to run badly from doing it again.

Lawn equipment that’s seasonally used is especially vulnerable to poor startups and performance. Things like snow blowers and chainsaws tend to get dirty on the inside. Leaving your equipment out in the rain could lead to their engines surging.

If this happens, the fastest way to stop it is by removing the water content that’s settled in the engine. Mechanic in a Bottle can absorb water content fast and have everything working better than it did before the surge occurred.

Know Which Product to Pick

All of the B3C products listed contain the same formula. The main difference is their quantity and size. Pick according to how much you plan on using from the start, or how much you’ll need in the future.

It’s always a good thing to have this at the ready during lawn care, and a little bit in the tank every month will help increase the life of your machinery. For more than one car, a larger one is better but a single four-ounce bottle should suffice in a single lawnmower tank.

Frequently Asked Questions

Is Mechanic in a Bottle Good for Diesel Engines?

The products shown above are for two and four-cycle engines, not diesel. However, B3C does produce Mechanic in a Bottle for diesel engines.

How much should be used in a single tank?

Follow the instructions that are listed on the bottle. The standard is one ounce per gallon in fuel tank size. You can go over this if you want, there’s no risk of adding too much.

How long will it take to see results?

Anywhere from four to 24 hours, depending on the preliminary methods taken before adding to the tank and the state of the engine and carburetor.


You don’t always have to go to a mechanic when there’s engine trouble. In many cases, the problems are solvable on your own, provided you have the right products at hand.

Mechanic in a Bottle can clean out your engine in ways that you might have thought impossible to do without replacing parts. See for yourself and choose one of the products reviewed, then get ready to say goodbye to all of your engine troubles!

John Billiou

John Billiou

LOCATION: Visalia, California


John Billiou assumed operations of the family business in 1989 with a “big appetite” for success.

Based in Central California, Billiou's Has been serving the Parts Needs of Lawn & Garden Dealers Across the Western United States for 70 Years.

Today, the company distributes new equipment and parts in 13 Western states and John said their No. 1 customers are cities and counties.

Billiou’s provides field support through their call center, field sales force, and an extensive website.

Billiou’s team strives to longstanding value to the customer and readers by making reliable and solid buying recommendations.

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