1990 johnson 140
I'm having trouble idling when in the water. It idles great on the muffs. Two weeks ago it idled perfectly in the water, and at the end of the day it wouldn't stay idling. Max RPMs 4200, normal max 5600. Idled at 500 in the water when it would, normally 750.
Spark test showed all 4 firing strong. The plugs are about a month old.
Cylinder drop test showed #3 bottom starboard cylinder with no change when the wire was pulled and #1 top starboard a noticeable change but not as much as both port wires. Both starboard wires snapped audibly as they got close to the plugs when putting them back on, and made it gain some audible rpms while they were jumping the gap to the plug, but it would drop again (barely any rise and fall but it was definitely audible) when the boot was fully back on.
Rebuilt #3 carb and it seemed to be fixed and idle sounded great on the hose and it passed the cylinder drop test. I just rebuilt the #1 about a month ago. I'm confident the passages are clean.
The #3 coil is about 6 weeks old. The #1 is about a year old. Seems trustworthy.
This weekend I put it in the water and it wouldn't idle again. In the water both starboard cylinders failed the drop test, with the same symptom when the boot got right near the plug.
Max RPMs were now 5000, where max is normally about 5600. It sounded and performed great over 3500.
Just checked the compression, all about 130.
Powerpack output (peak reader and home made PL-88) at cranking speed is
#1 231
#2 251
#3 232
#4 257
I think the starboard 1&3 being lower but equal can be attributed to the fact that they used a horrible ground but it was the best I could reach with the tools I had hooked up to it. Either way the passing score in my manual is 160 so it seems safe to say that it's fine.
I do plan on swapping both port coils to the starboard side just to be 100% on them, but seeing as they're new it seems like more of a formality.
Since the output to the coil primaries is good, is there any reason to test other ignition components? I have a factory manual but at this point I'm looking at Lots of tests which are probably a bit redundant considering what I've already confirmed. I could do the carbs Again but I just put new kits in them, hosed them with cleaner, removed the jets, and blew out the passages with a compressor.
So what next?
I'm having trouble idling when in the water. It idles great on the muffs. Two weeks ago it idled perfectly in the water, and at the end of the day it wouldn't stay idling. Max RPMs 4200, normal max 5600. Idled at 500 in the water when it would, normally 750.
Spark test showed all 4 firing strong. The plugs are about a month old.
Cylinder drop test showed #3 bottom starboard cylinder with no change when the wire was pulled and #1 top starboard a noticeable change but not as much as both port wires. Both starboard wires snapped audibly as they got close to the plugs when putting them back on, and made it gain some audible rpms while they were jumping the gap to the plug, but it would drop again (barely any rise and fall but it was definitely audible) when the boot was fully back on.
Rebuilt #3 carb and it seemed to be fixed and idle sounded great on the hose and it passed the cylinder drop test. I just rebuilt the #1 about a month ago. I'm confident the passages are clean.
The #3 coil is about 6 weeks old. The #1 is about a year old. Seems trustworthy.
This weekend I put it in the water and it wouldn't idle again. In the water both starboard cylinders failed the drop test, with the same symptom when the boot got right near the plug.
Max RPMs were now 5000, where max is normally about 5600. It sounded and performed great over 3500.
Just checked the compression, all about 130.
Powerpack output (peak reader and home made PL-88) at cranking speed is
#1 231
#2 251
#3 232
#4 257
I think the starboard 1&3 being lower but equal can be attributed to the fact that they used a horrible ground but it was the best I could reach with the tools I had hooked up to it. Either way the passing score in my manual is 160 so it seems safe to say that it's fine.
I do plan on swapping both port coils to the starboard side just to be 100% on them, but seeing as they're new it seems like more of a formality.
Since the output to the coil primaries is good, is there any reason to test other ignition components? I have a factory manual but at this point I'm looking at Lots of tests which are probably a bit redundant considering what I've already confirmed. I could do the carbs Again but I just put new kits in them, hosed them with cleaner, removed the jets, and blew out the passages with a compressor.
So what next?