Marco Flamingo
Active member
Another post reminded me to post about my Suzuki 2.5 outboard idle problems. It is addressed other places on the web, but the solutions were various and, as is often the case, sometimes people who resolve the problem don't come back to the thread when they have found the solution. Here is my experience.
The Suzuki 2.5 has an incredibly small idle jet orifice. One solution was to go to the next larger size jet. I had fiddled with all the settings on my 2.5 to try to get it to idle, but with no success. I had to go directly from a half-choke fast idle directly into gear at partial throttle. Hard on the engine. Idle wasn't possible and when used on my little aluminum kicker, idle is just the right speed for trolling. Very frustrating that it worked perfectly for a few months and then would not idle.
I ordered the larger jet and a little carburetor jet cleaning tool (a series of thin wires) and when they arrived I pulled out the jet. I couldn't see light through it, and even the smallest cleaning wire was too large to pass through the jet. I have no idea how they manufacture a jet with that tiny of a passage. Before I installed the larger jet, I washed off the original, put it in my lips, and sucked. I could tell that I popped loose a tiny (carcinogenic) obstruction. I shot carb cleaner through it and reinstalled. Problem fixed. Almost.
I am very careful with making sure that my gas is clean because I knew that the 2.5 carb would be very sensitive to crud in the gas. I use an extremely fine filtering funnel when filling as there is no filter between the carb and the tank. In fact, there is no space there to put a filter (I tried). But I did find the source of the tiny particles that I found when I drained and flushed the tank.
The gas fill cap is on a tether, as is common with small outboards. The cap end of the tether has a large washer. If you remove that washer, you will find two problem areas. One is that behind the washer is a fiber disc "air filter" material that is quite coarse. It would keep out knats and small stones, but not all matter large enough to choke off the slow idle jet. But the main problem with the material is that it degrades. I could see that some of it had hardened (maybe from exposure to gas fumes?) and fallen apart. The only place that those tiny pieces could go is down into the tank. I removed what was left and will take my chances with knats.
The second problem was that the large washer is coated steel (zinc, cadmium?). There was apparently sufficient condensation in the little tank such that the washer had corroded (especially the backside that isn't visible). I could "dust off" some type of oxidation. Again, pieces that were just the right size to go unnoticed but large enough to clog the Suzuki 2.5 idle jet. Since the washer's purpose was to hold the crumbling "air filter," and that was now gone, I didn't replace the washer. The retaining tether works fine without it. I had removed both sources of obstructing particles from inside the tank.
The 2.5 has a white gas tank, so any little particles are fairly easy to see if they are sitting at the bottom. But I need to remember to keep an eye on that. Hope this helps somebody who has this issue with an otherwise wonderful little motor.
Mark
The Suzuki 2.5 has an incredibly small idle jet orifice. One solution was to go to the next larger size jet. I had fiddled with all the settings on my 2.5 to try to get it to idle, but with no success. I had to go directly from a half-choke fast idle directly into gear at partial throttle. Hard on the engine. Idle wasn't possible and when used on my little aluminum kicker, idle is just the right speed for trolling. Very frustrating that it worked perfectly for a few months and then would not idle.
I ordered the larger jet and a little carburetor jet cleaning tool (a series of thin wires) and when they arrived I pulled out the jet. I couldn't see light through it, and even the smallest cleaning wire was too large to pass through the jet. I have no idea how they manufacture a jet with that tiny of a passage. Before I installed the larger jet, I washed off the original, put it in my lips, and sucked. I could tell that I popped loose a tiny (carcinogenic) obstruction. I shot carb cleaner through it and reinstalled. Problem fixed. Almost.
I am very careful with making sure that my gas is clean because I knew that the 2.5 carb would be very sensitive to crud in the gas. I use an extremely fine filtering funnel when filling as there is no filter between the carb and the tank. In fact, there is no space there to put a filter (I tried). But I did find the source of the tiny particles that I found when I drained and flushed the tank.
The gas fill cap is on a tether, as is common with small outboards. The cap end of the tether has a large washer. If you remove that washer, you will find two problem areas. One is that behind the washer is a fiber disc "air filter" material that is quite coarse. It would keep out knats and small stones, but not all matter large enough to choke off the slow idle jet. But the main problem with the material is that it degrades. I could see that some of it had hardened (maybe from exposure to gas fumes?) and fallen apart. The only place that those tiny pieces could go is down into the tank. I removed what was left and will take my chances with knats.
The second problem was that the large washer is coated steel (zinc, cadmium?). There was apparently sufficient condensation in the little tank such that the washer had corroded (especially the backside that isn't visible). I could "dust off" some type of oxidation. Again, pieces that were just the right size to go unnoticed but large enough to clog the Suzuki 2.5 idle jet. Since the washer's purpose was to hold the crumbling "air filter," and that was now gone, I didn't replace the washer. The retaining tether works fine without it. I had removed both sources of obstructing particles from inside the tank.
The 2.5 has a white gas tank, so any little particles are fairly easy to see if they are sitting at the bottom. But I need to remember to keep an eye on that. Hope this helps somebody who has this issue with an otherwise wonderful little motor.
Mark