Hi,
I've got a 1980 Johnson (V4 Crossflow) that isn't running well. Over the next few days I'm going to be troubleshoot it and am hoping to use this discussion to get some questions answer as I go.
Symptoms are one bank intermittently not fireing. Even before that the boat didn't idle well. I have cleaned and rebuilt the carbs, the problems appear to be ignition related.
A couple of questions. And a few results from last night's trouble shooting. (I didn't get a chance to start the boat last night, so tests that require it running will have to wait for tonight.
Question 1: I only get about 250 RPMs when cranking. Is that enough to check for spark & measure stator voltages & compression, or do I need to get it above 300 RPM?
Question 2: The rectifier is definitely bad. Is it safe to replace the rectifier before figuring out what else is wrong, or do I risk damaging the new rectifier if I don't replace all the bad parts at once.
Question 3: I have weak spark on both cylinders on the right bank ((spark will jump about 3/16 gap with some "misses"), none on the left. Out of curiosity I checked the coil resistances (Primary to Ground). The bottom coils on both sides measure about 270 Ohms. However the top coil on the working bank showed an open circuit when I tried to measure resistance (Interestingly, this coil has been replaced at some point, all the other coils appear to be original). Resistance on the top coil on the non-working bank was about 2000 Ohms. Given those open / high measurements would you assume coils are bad (even though I get a spark from the one that shows as open)?
Question 4: For measuring voltages from the stator and timer. I have back probes I can use to try to probe into the connector, or piercing probes. What works best?
All advice appreciated.
I've got a 1980 Johnson (V4 Crossflow) that isn't running well. Over the next few days I'm going to be troubleshoot it and am hoping to use this discussion to get some questions answer as I go.
Symptoms are one bank intermittently not fireing. Even before that the boat didn't idle well. I have cleaned and rebuilt the carbs, the problems appear to be ignition related.
A couple of questions. And a few results from last night's trouble shooting. (I didn't get a chance to start the boat last night, so tests that require it running will have to wait for tonight.
Question 1: I only get about 250 RPMs when cranking. Is that enough to check for spark & measure stator voltages & compression, or do I need to get it above 300 RPM?
Question 2: The rectifier is definitely bad. Is it safe to replace the rectifier before figuring out what else is wrong, or do I risk damaging the new rectifier if I don't replace all the bad parts at once.
Question 3: I have weak spark on both cylinders on the right bank ((spark will jump about 3/16 gap with some "misses"), none on the left. Out of curiosity I checked the coil resistances (Primary to Ground). The bottom coils on both sides measure about 270 Ohms. However the top coil on the working bank showed an open circuit when I tried to measure resistance (Interestingly, this coil has been replaced at some point, all the other coils appear to be original). Resistance on the top coil on the non-working bank was about 2000 Ohms. Given those open / high measurements would you assume coils are bad (even though I get a spark from the one that shows as open)?
Question 4: For measuring voltages from the stator and timer. I have back probes I can use to try to probe into the connector, or piercing probes. What works best?
All advice appreciated.
