The engine is a 1990 40HP Tracker/Johnson
I have replaced the ignition system for the fourth time now. It's a long story but.
The original one was randomly double firing at idle speed. this caused the engine to sometimes stall, and always cough at idle. The second one was stuck in "slow mode". Life was much better at idle, but it would crap out if you pushed it above 2600RPM, The thrid one may have been ok untill it's I shorted it's gnd wire to a 12v source during it's installation. The fourth one has been properly installed w/o damage!
On Sat, the boat ran up to about 4400RPM at WFO with two people a a bunch of gear. The problem is it will still misfire, or cough at idle some times.
We were trolling all day, the boat still smells rich (gas not oil). If I attempt to lean it out, it will stall. The tack says that we are doing about 1000RPM at idle. What can I do to improve it's performance at idle? I would like to be able to troll for trout. The min idle speed was 2.4kts. The carbs have been cleaned about 3 times. The timing looks good to me. At idle it's about 2.5 deg retarded, when tested at full trottle (with the engine not running) it seems to be at about 15 deg advanced. The spec says 19 deg. I have been looking for problems ignition problems in the dark. Other than a corona glow around the plugs I have not found anything.
What do you think. Bad wire? The plugs are fresh. I reduced the gap to 0.03" from 0.035"
for Sat. test. I would really like to put this one to bed.
Below is some previous post.
PS, FUI when you install your new CD unit, remember to disconnect the battery
It will save you $90 and about a week.
Some History
After all of my work, I took the boat out on the water on Sat. It started and ran OK in the morning. It even idled like a normal boat. I spent about 3 hours trolling that day. We were doing about 2 knts at about 1050 rpm (a little high). The engine stalled about a dozen or more times. It would tool along just great for a while, then it would get into a funk where it would pop or misfire. It's diffinately through the exhust. On the water you can bearly here it. But the engine would shake, there would be a little puff of smoke and the rpm's would drop a bit. If these little hichups occure too close together it stalls. It always starts right up after it stalls. I did adjust the carbs on the water at idle. I'm not sure it helped. It's really doing much better, but I need it to troll at about 800, or 900 RPM. There were no issues with it loading up at idle. It was not quite happy or smooth. It's got great compression and should do better.
After work, when it gets a little dark, I will use the timming light to serach for missfires on the lower cylin. The last time I was only looking at the top cyln.
Also it idled a lot better on the water than I had been on the hose.
Is this a power pack problem?
How do I tell?
See some history below:
I have a 1990 40 HP tracker Johnson.
I do not know a lot about it's history but it has never ran right.
I have worked on and owned it for almost 2 months now.
It runs great at speed, but has never been willing to idle on the water.
It idle on the muffs, usually not great. The VRO was injection way too much oil at idle.
To date, I have gone through the carbs twice.
I have a manual. I have properly adjusted the carbs, synced, and checked the timing at idle.
The latest change was to delete the oil injection and go to premix. the could is gone.
Here is the issue, at idle on the muffs, it pops, when it's up to temperature it runs about 2 sec. and pops. Adjusting the carbs does not seem to effect the poping. If I use the timming light I do not see anything wrong when it pops on ether cylinder. When it pops, there is a little cloud of oil smoke and the engine slows down. This problem is being caused by the top cylinder only. If I disconnect the top plug (and ground it) it idles much better better, no poping.
You can adjust the lower carb with no problems. It seems the poping is the upper cylinder firing out of phase at idle. I do not see any other evidence of this. No stray arcs, no mis located timing light firing. On Sunday she would run at 5200RPM across the lake and die at idle. If it run on the top cylinder only she will not start, she jsut runs about 1 sec and dies.
That is a bunch of info guys, so what is wrong? I will take another look for arc in the dark. My next test will be to switch the connections on the coil to see if I can move the problem to the lower cylinder.
Update!
I tried the spray, it can make the engine run worse, but not better. I checked the connections and grounds, they look good. I swapped the coil connections. It ran the same. Here is the big clue. After I swapped the coil connections I noted it would run on the top cyln. I adjusted the carb. It will also run on the lower cyln. It is not related to swapping the coils, I swapped them back. Same results. It runs better on ether cylinder than on both. On a single cyln it will run pretty smoothly at a lower speed. With both cylinders it will run smoothly for about a min, them it will start to pop. The pop seems like an out of phase firing. it slows the engine. It produces a little cloud of smoke. If they occure in sequence the engine will stall. If the engine is cold it is much more likely to stall. With the timming light, I have not been seeing a missed shot. I replaced the plugs, set the gaps at 0.03. I ran it a little while. It seemed to have a little bump or hitch in it's step at first. But soon enough, it was pop run run run run pop, run run run run pop run pop run run run pop.
Come on guys what's wrong here?
I have replaced the ignition system for the fourth time now. It's a long story but.
The original one was randomly double firing at idle speed. this caused the engine to sometimes stall, and always cough at idle. The second one was stuck in "slow mode". Life was much better at idle, but it would crap out if you pushed it above 2600RPM, The thrid one may have been ok untill it's I shorted it's gnd wire to a 12v source during it's installation. The fourth one has been properly installed w/o damage!
On Sat, the boat ran up to about 4400RPM at WFO with two people a a bunch of gear. The problem is it will still misfire, or cough at idle some times.
We were trolling all day, the boat still smells rich (gas not oil). If I attempt to lean it out, it will stall. The tack says that we are doing about 1000RPM at idle. What can I do to improve it's performance at idle? I would like to be able to troll for trout. The min idle speed was 2.4kts. The carbs have been cleaned about 3 times. The timing looks good to me. At idle it's about 2.5 deg retarded, when tested at full trottle (with the engine not running) it seems to be at about 15 deg advanced. The spec says 19 deg. I have been looking for problems ignition problems in the dark. Other than a corona glow around the plugs I have not found anything.
What do you think. Bad wire? The plugs are fresh. I reduced the gap to 0.03" from 0.035"
for Sat. test. I would really like to put this one to bed.
Below is some previous post.
PS, FUI when you install your new CD unit, remember to disconnect the battery
It will save you $90 and about a week. Some History
After all of my work, I took the boat out on the water on Sat. It started and ran OK in the morning. It even idled like a normal boat. I spent about 3 hours trolling that day. We were doing about 2 knts at about 1050 rpm (a little high). The engine stalled about a dozen or more times. It would tool along just great for a while, then it would get into a funk where it would pop or misfire. It's diffinately through the exhust. On the water you can bearly here it. But the engine would shake, there would be a little puff of smoke and the rpm's would drop a bit. If these little hichups occure too close together it stalls. It always starts right up after it stalls. I did adjust the carbs on the water at idle. I'm not sure it helped. It's really doing much better, but I need it to troll at about 800, or 900 RPM. There were no issues with it loading up at idle. It was not quite happy or smooth. It's got great compression and should do better.
After work, when it gets a little dark, I will use the timming light to serach for missfires on the lower cylin. The last time I was only looking at the top cyln.
Also it idled a lot better on the water than I had been on the hose.
Is this a power pack problem?
How do I tell?
See some history below:
I have a 1990 40 HP tracker Johnson.
I do not know a lot about it's history but it has never ran right.
I have worked on and owned it for almost 2 months now.
It runs great at speed, but has never been willing to idle on the water.
It idle on the muffs, usually not great. The VRO was injection way too much oil at idle.
To date, I have gone through the carbs twice.
I have a manual. I have properly adjusted the carbs, synced, and checked the timing at idle.
The latest change was to delete the oil injection and go to premix. the could is gone.
Here is the issue, at idle on the muffs, it pops, when it's up to temperature it runs about 2 sec. and pops. Adjusting the carbs does not seem to effect the poping. If I use the timming light I do not see anything wrong when it pops on ether cylinder. When it pops, there is a little cloud of oil smoke and the engine slows down. This problem is being caused by the top cylinder only. If I disconnect the top plug (and ground it) it idles much better better, no poping.
You can adjust the lower carb with no problems. It seems the poping is the upper cylinder firing out of phase at idle. I do not see any other evidence of this. No stray arcs, no mis located timing light firing. On Sunday she would run at 5200RPM across the lake and die at idle. If it run on the top cylinder only she will not start, she jsut runs about 1 sec and dies.
That is a bunch of info guys, so what is wrong? I will take another look for arc in the dark. My next test will be to switch the connections on the coil to see if I can move the problem to the lower cylinder.
Update!
I tried the spray, it can make the engine run worse, but not better. I checked the connections and grounds, they look good. I swapped the coil connections. It ran the same. Here is the big clue. After I swapped the coil connections I noted it would run on the top cyln. I adjusted the carb. It will also run on the lower cyln. It is not related to swapping the coils, I swapped them back. Same results. It runs better on ether cylinder than on both. On a single cyln it will run pretty smoothly at a lower speed. With both cylinders it will run smoothly for about a min, them it will start to pop. The pop seems like an out of phase firing. it slows the engine. It produces a little cloud of smoke. If they occure in sequence the engine will stall. If the engine is cold it is much more likely to stall. With the timming light, I have not been seeing a missed shot. I replaced the plugs, set the gaps at 0.03. I ran it a little while. It seemed to have a little bump or hitch in it's step at first. But soon enough, it was pop run run run run pop, run run run run pop run pop run run run pop.
Come on guys what's wrong here?