Many thanks for the responses.
Boobie, re: compression, the seller indicated that, in February 2019, he had tested and found all cylinders between 125-130, but I did not test myself and I will go and buy a compression tester and test this myself. Taking the lead from used cars I've purchased, the first thing I did was replace the plugs and wires. After the failure in the bay, I tried an initial spark test using a screwdriver, but must not have done it correctly, since I could not find evidence of a spark, and the motor has since started ... will get to that in a moment, but I am hearing from multiple directions that these motors can start and sound OK with only 2 or 3 cylinders working. Will test spark properly.
joereeves, thank you and I will fully adopt nautical terminology. Sorry for the confusion. I as actually making this same point to my wife this afternoon
Will follow your guide for building a spark tester.
riopga, and all, for your patience. I hate to admit it, as I hate to see people on other forums (e.g. homebrewtalk.com) who ask a question that's been asked and answered a million times already, but I only gave a cursory skim of the posts here before tossing my question in. I've already learned a ton over the past few days, and I'm already grateful to the generosity of the boating community here online as well as around Baltimore and on the Chesapeake.
I will get more specific data and post information here as I collect it, but in the spirit of "
Give these fine gentlemen as much info as possible", here's what I've learned this weekend:
The guy who sold me the motor suspected there was a fuel problem. He walked me through a few steps, including an application of starter fluid. This got the motor started (well, wailing for a moment or two, and then running), but after it burned through the starter fluid, it idled for a bit and then stalled again. He said "there's a spark, you just need to check all of your fuel connections". The next morning, I double-checked the fuel connections in the powerhead, and everything was tight, with no leaks. Also, after replacing the fuel pump, I found no leaks when pressurizing the system or when turning over. I also confirmed that the primer solenoid was squirting by removing a hose and activating the primer. I put earmuffs on the motor and tried to start the motor, and it turned over and idled. I turned it off and tried again, and it worked - I was even able to put it in gear. The seller said there might have been air in the system and I just needed to give it a kick (starter fluid) to get things moving.
The next day, I launched the boat and while I was able to get it to turn over and idle, it would stall whenever I put it in gear. I learned that if I pressed the primer as I was putting it in gear, I could keep it from stalling and get it in gear, but it would only piddle about for about a minute before stalling again. I increased the idle speed a bit (I don't have a tachometer so I can't give you specifics, but I turned the idle screw one or two full rotations to increase idle speed) and that helped to keep from stalling when I put it in gear, but it would still stall shortly after going into gear, and specifically if I increased the throttle too much. It was hard-starting on roughly half of the attempts that we made. We found that if we took the hood off and pulled back the throttle when starting, and then had someone pumping the fuel bulb intermittently, and if I pressed the primer intermittently, we could keep the motor going long enough to piddle around a little bit, leading us to think that the seller was right: there's still a fuel issue. As I was retrieving the boat, someone else who was launching complimented the motor, and I said "I wish I could get it to run." Upon telling him the symptoms, he said "you have to make sure all of your fuel connections are solid". Later that evening, when unpacking the boat, I found a possible culprit: there was no hose clamp on the fuel hose connection to the fuel tank. I can't believe I launched without having a hose clamp on the fuel hose at the fuel tank. I promise you, I am generally not a complete idiot, but this was a really questionable moment. I put a clamp on the connection (all other connections were properly clamped), put ear muffs on the motor, and she started up without hesitation. I let it idle for a minute, put it in gear, the propeller turned, I gave it some throttle, the motor responded, put it in neutral and it idled, put it in reverse and the propeller turned in reverse, put it back into idle, it idled, and I thought I had succeeded.
Launched her this morning to the same problem: a little hard starting, but would idle and then stall when putting in gear. When I got the motor started, it would often come with a cloud of smoke. A gentleman on the dock was watching me struggle with getting the motor starter, said he was a diesel mechanic and given the sound of the motor and the blue smoke, he knew it was a dirty carburetor, and suggested I just use a shot of starter fluid to get things going (I'm sensing a theme here). I didn't have starter fluid with me, and we were sufficiently frustrated that we just retrieved the boat and came home. I didn't want to leave salt water or brackish water in the motor, so I put ear muffs on with fresh water and started one more time at home hoping to get it running enough to flush the cooling system. It started up without hesitation. I let it idle for a minute, put it in gear, the propeller turned, I gave it some throttle, the motor responded (where on the water, increasing throttle would lead to a stall) and kept running, I put it in neutral and it idled, put it in reverse and the propeller turned in reverse, put it back into idle, it idled, and I realized that a variable here was whether or not the prop was under load (e.g. water). I then continued to let it idle and it stalled after about another 15 seconds. The night before, when I thought I had succeeded at home, I probably just hadn't given it enough time to stall.
Reading through the SELOC manual, it looks to me like the two possible culprits that seem constant across the various symptoms that I have are either fuel restrictions or a messy carburetor. I feel like I've worked through the fuel system now thoroughly from the tank to the carburetor. I'm mechanically inclined and found carb rebuild kits online, and I bet it couldn't hurt to rebuild the carbs because then I will know that this is not a variable, and I would start with a clean slate there, but before jumping into that, I am going to make sure to test compression and properly test spark.
I have since poked around and learned about the dangers of starter fluid in outboards (e.g. no lubrication). I also realize that I my problems may reside at least partially in my cold-start procedures. I've basically been following these procedures:
https://forums.iboats.com/forum/eng...231251-johnson-evinrude-cold-start-procedures
However, I'm not entirely sure I've given the motor the proper time to warm up before trying to put it in gear ... it's not clear to me what amount of time is needed. For the most part, when I get it started, the motor runs at faster revolutions than when otherwise idling, so I've assumed that the motor is ready to put in gear when it the revs upon starting have died down to an idling speed, but also: remembering back to older cars I've had (e.g. 1975 Chevy Nova), best warm-up times were typically longer than I've been giving this outboard.
Anyway, sorry for rambling, thank you so much for your patience and advise, I will get specific numbers for compression and specific spark info, and post back here.
