The Metering Lever: A Common Cause of Bogging Down in Two-Stroke Engines

In this eighth video of our 12-part series, we're going to explore one of the most common causes of bogging down in two-stroke engines. The metering lever is a critical component that plays a crucial role in regulating fuel flow into the engine. In this section, we'll examine how the diaphragm interacts with the metering lever and what happens when it's set too low.

The metering lever is designed to work in conjunction with the diaphragm to provide the correct amount of fuel for the engine. When the diaphragm moves down, it pushes on the back of the lever, which allows just enough fuel to flow through. There's a small gap between the back of the lever and the diaphragm plunger that must be maintained in order for the engine to run smoothly. However, if the back of the lever is set too low, due to its metal construction allowing it to be bent, this can cause problems.

Imagine the back of the lever as having low setting. If it's set too low, it means that the metal has been bent down, which will lead to similar issues to a short plunger. The needle valve won't be lifted high enough, preventing enough fuel from flowing through the engine. Even though the diaphragm is working perfectly and traveling down as it should, it can't lift the front of the lever high enough to allow fuel to flow into the metering area.

As a result, there's a small gap that prevents fuel from coming through quickly enough to feed the top of the metering area. This, in turn, means there will be less fuel available for the main jet and ultimately, the engine. The working scenario is similar to the previous one, where the piston cycles cause less fuel to flow in each time the engine revs high. Eventually, this leads to bogging down.

It's worth noting that the correct setting for metering levers can vary between different types of carburetors. Some may need to be adjusted as far up as level with the top of the carburetor body, while others may need to be flush with the bottom of the metering body. In this video, we're not going into the details of how to adjust these levers exactly; however, I will make a separate video on this topic.

In fact, there's already a wealth of great content available online about how to adjust metering levers. If you suspect that your metering lever is set too low like in this scenario, it's easy enough to bend back into the correct position because it's made of thin metal.

"WEBVTTKind: captionsLanguage: enthank you for clicking through to this video which is number eight of 12 and on this particular video it's the metering lever which can cause bug down for two-stroke engines I have uploaded the full version the 12 reasons but I've broke them down just to make it simpler and a little easier to find the content so let's assume all's well there so we'll move on now to my eighth reason for bugging down and that's the metering lever so just looking once again at how the diaphragm interacts with the metering lever we can see it comes down and it pushes on the back of that lever just enough for the correct amount of fuel to come through as we've already mentioned and again we've already mentioned that there's a correct space in there between the back of the lever and the diaphragm plunger let's now imagine the back of that lever as you can see there is low so it's set too low because the lever itself is made of metal the back of this lever can be set so that the metal can be bent in order to adjust the back of this lever and sometimes what can happen is this can be set too low if that's the case then this is what happens it's a similar scenario to having a short plunger in fact the results exactly the same the needle valve is now not being lifted high enough again not allowing enough fuel through so although the diaphragm is now correct and working perfectly it can't possibly travel down far enough to lift the front there at the needle valve to allow fuel to come through and the result again is this small gap which won't allow enough fuel through for ey engine revs and although there's enough fuel available below here it won't be able to come through that small Gap quick enough to feed the top of the metering area here and then of course as we've already explained there'll be less available for the main jet here and then of course in turn there'll be less available for the engine so taking a look at the working scenario here it's the same Outlook as the last scenario each time the Piston Cycles we've got less fuel going in each time the engine revs high So eventually we've got bog down and in this case it's all because that lever is angled Too Far Low at the back again this is another thing that's often overlooked so if you do suspect that your metering lever is over adjusted like this then it's easy enough to bend back into the right area because it's only made of a thin metal now the correct setting for these do vary between different types of carburetor some you have to adjust as far up as level with the top of the carburetor body and some have to be flush with the bottom of the metering body but it's not my intention in this particular video to go into how to adjust these exactly I just wanted to show you how they relate to bogging down but I will put a video on regarding the adjustments and in fact I have noticed that there's already a lot of great content out there on YouTube about how to adjust these so thank you for watching this short video I wanted to keep it short and sweet to keep it direct to the point and please check out my next video which is number n 9 and that's on the meter in Spring again thank you for watchingthank you for clicking through to this video which is number eight of 12 and on this particular video it's the metering lever which can cause bug down for two-stroke engines I have uploaded the full version the 12 reasons but I've broke them down just to make it simpler and a little easier to find the content so let's assume all's well there so we'll move on now to my eighth reason for bugging down and that's the metering lever so just looking once again at how the diaphragm interacts with the metering lever we can see it comes down and it pushes on the back of that lever just enough for the correct amount of fuel to come through as we've already mentioned and again we've already mentioned that there's a correct space in there between the back of the lever and the diaphragm plunger let's now imagine the back of that lever as you can see there is low so it's set too low because the lever itself is made of metal the back of this lever can be set so that the metal can be bent in order to adjust the back of this lever and sometimes what can happen is this can be set too low if that's the case then this is what happens it's a similar scenario to having a short plunger in fact the results exactly the same the needle valve is now not being lifted high enough again not allowing enough fuel through so although the diaphragm is now correct and working perfectly it can't possibly travel down far enough to lift the front there at the needle valve to allow fuel to come through and the result again is this small gap which won't allow enough fuel through for ey engine revs and although there's enough fuel available below here it won't be able to come through that small Gap quick enough to feed the top of the metering area here and then of course as we've already explained there'll be less available for the main jet here and then of course in turn there'll be less available for the engine so taking a look at the working scenario here it's the same Outlook as the last scenario each time the Piston Cycles we've got less fuel going in each time the engine revs high So eventually we've got bog down and in this case it's all because that lever is angled Too Far Low at the back again this is another thing that's often overlooked so if you do suspect that your metering lever is over adjusted like this then it's easy enough to bend back into the right area because it's only made of a thin metal now the correct setting for these do vary between different types of carburetor some you have to adjust as far up as level with the top of the carburetor body and some have to be flush with the bottom of the metering body but it's not my intention in this particular video to go into how to adjust these exactly I just wanted to show you how they relate to bogging down but I will put a video on regarding the adjustments and in fact I have noticed that there's already a lot of great content out there on YouTube about how to adjust these so thank you for watching this short video I wanted to keep it short and sweet to keep it direct to the point and please check out my next video which is number n 9 and that's on the meter in Spring again thank you for watching\n"