BoatThings
Cadet
- Joined
- May 17, 2016
- Messages
- 23
Got a sudden loss of power accompanied by a nasty racket out on the water. Immediately checked the pee stream, good flow and temp was fine, killed the engine, checked around inside the cover, no overheating. Was out camping in the canoe, and on the way back to the vehicle. Still pretty far out, so I figured I try to start it again. Harder to start than usual but came back to life and ran fine for another 20 minutes or so, then did the same thing.
Got it home now and pulled the plugs to check compression, found the bottom plug completely wet with fuel, (might be hard to see in the pics, but the fuel is actually bridging the electrodes) first instinct is that it's running one one cylinder from an ignition problem. Check compression to make sure it's not the head gasket, or something worse. Got 60 on top, which is normal when it's dry, and 90 on the bottom, which is normal when it's wet, which the bottom was, quite wet, while the top was dry. I still see spark on both plugs out of the cylinders, and when I put them back in to check under compression with an inline spark test light, they also both work. Upon checking the ignition coils, I found the primaries good, but both secondaries are out, the bottom around 1300 ohm and the top is around 1500 ohm, when I believe they are supposed to be 275 +/- 50 ohms.
Seems to me I have some weak coils, visual inspection also shows a crack on the plastic covering of the top coil, and even though it's more out of spec, it seems to be the bottom one cutting out, possibly from heat expansion.
Even if the problem lies elsewhere, looks like I'm in need of some new coils, but I have no experience with small two stroke marine engines, this is my first, so I thought I'd bounce this around to get any other possible ideas to make sure I'm on the right track.
On a side note, all of my attempted restarts also broke my pull rope, so I replaced that, and then discovered my pinion gear was cracked at the top, so I 3D printed a reinforcing collar and epoxied it back together. Might also be running a little rich in general, but these plugs are 3 years old, I probably only use the motor for less than 10 hours per year.
Got it home now and pulled the plugs to check compression, found the bottom plug completely wet with fuel, (might be hard to see in the pics, but the fuel is actually bridging the electrodes) first instinct is that it's running one one cylinder from an ignition problem. Check compression to make sure it's not the head gasket, or something worse. Got 60 on top, which is normal when it's dry, and 90 on the bottom, which is normal when it's wet, which the bottom was, quite wet, while the top was dry. I still see spark on both plugs out of the cylinders, and when I put them back in to check under compression with an inline spark test light, they also both work. Upon checking the ignition coils, I found the primaries good, but both secondaries are out, the bottom around 1300 ohm and the top is around 1500 ohm, when I believe they are supposed to be 275 +/- 50 ohms.
Seems to me I have some weak coils, visual inspection also shows a crack on the plastic covering of the top coil, and even though it's more out of spec, it seems to be the bottom one cutting out, possibly from heat expansion.
Even if the problem lies elsewhere, looks like I'm in need of some new coils, but I have no experience with small two stroke marine engines, this is my first, so I thought I'd bounce this around to get any other possible ideas to make sure I'm on the right track.
On a side note, all of my attempted restarts also broke my pull rope, so I replaced that, and then discovered my pinion gear was cracked at the top, so I 3D printed a reinforcing collar and epoxied it back together. Might also be running a little rich in general, but these plugs are 3 years old, I probably only use the motor for less than 10 hours per year.