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How to Avoid Problems Caused by Stale Petrol?

March 04, 2022 3 min read

How to Avoid Problems Caused by Stale Petrol?
  What makes petrol stale? Petrol deteriorates quicker than you might realise. Within 1 month, even when stored correctly, its qualities decline, causing performance issues. This is usually experienced as a ‘fading’ or ‘power loss’ when using your machine. Additionally, the ethanol (the solvent that exists in varying concentrations in petrol) attracts water particles, which sink to the bottom, where bacteria start to breed and cause corrosion. In such cases, replacing parts like the carburettor, fuel pumps or valves may be necessary. But do not worry, good maintenance can prevent this from happening. Which kind of petrol can be used in Honda engines? Honda recommends using regular unleaded 98, 95, 95 E5 (5% ethanol) or E10 (10% ethanol). Anything over 10% will cause trouble with starting and performance. It may also damage metal, rubber and plastic components of the machine. If you anticipate more than a 4-week gap between each usage of your Honda engine, you should only use petrol that has been treated with fuel stabiliser. Like other such products, the Honda fuel stabiliser comes with a shelf-life of two years, with its performance decreasing over time. One thing to note is that it will not reinvigorate stale petrol. This is why it’s important you add it to fresh petrol. How long should you leave petrol in the tank? There are many factors that can affect the petrol’s quality. One of them is the amount of air in a partially filled tank – we often forget to top up, or to use only the amount necessary on the job. This leads to fuel deterioration which may happen in less than 30 days. High or variable temperatures and a high level of humidity would also influence the petrol’s performance. At this point, you may be put off by all these things that can affect petrol. However, one of the most important things is to purchase fuel from a busy fuel station in a volume that will be used in less than three months. Only buy as much as you need and store it away from direct sunlight, in a jerrycan or suitable container that has not been corroded. How to take care of your Honda engine correctly? Simple steps go a long way here. Before each use, do a quick inspection of the engine oil level, and air filter which should always be clean. When the machine is no longer in use, ensure the fuel tap has been turned off. For winter storage, you can either drain the petrol from the carburettor and fuel tank, or you can add fuel stabiliser. If you choose the latter, you should fill the tank to the recommended level and run the engine for at least five minutes to allow stabilised petrol to enter the carburettor. The fuel has gone stale in my engine and now it's losing power. What can I do? The first thing to do is empty all the fuel out of the engine, start the engine (it will start with the residual fuel), and let the engine run until it cuts out. You have now removed all the old fuel from the engine. Fill the engine up with new, fresh fuel and test the machine. It should be running like new again. If not, you need to delve a little deeper as the stale fuel will have worked its way into the engine. The carburettor will need a clean, ideally using ‘carb cleaning pins’, (the increasingly popular ultrasound method sometimes doesn’t get to all the corner, we prefer the old fashioned pin method). The fuel filter may also need changing. After following these steps your engine should run like new.   These are the most commonly asked questions when it comes to petrol, or petrol operated machinery. Of course, you should use these guidelines in conjunction with the Owner’s Manual supplied with your Honda engine. For any questions, you are more than welcome to email us at or call us on 0114 269 9119 for technical support!