1999 Johnson 150hp Outboard Progressively Worse Starting Problems

[CapnRon]

The first summer I used this motor (4 years ago) the motor always started whether cold or hot. The second summer, the motor started OK everytime but once when we got stranded for an hour after going to the opposite side of the Lake and other times I noticed some "missing" when cruising and twice it just died while running. Last summer we got stranded everytime we went out but after it cooled off I could start it with some trouble. A mechanic replaced the fuel/oil pump and the filters along with the ignition switch (kill switch has never worked before or after replacement) and was fooled into thinking he had fixed it until I took him out for extended run and the sudden misses started just like two years earlier but the last time out it started when hot as long as I did not choke. This year it does not even act like it wants to start (even though it is turning over). Put "heet" in the fuel tank and replaced primer bulb and fuel line. Checked for water in gas with the color change paste. Replaced plugs last year but rechecked them and they are fine. Pumped "fresh" gasoline into engine but nothing works. The flywheel is turning and the kill switch at the motor appears to be working but the last time I saw the mechanic he was examining the switch and was thinking a short possibly. I am in Arkansas so I keep the boat and motor in the water with motor vertical. The only "winterizing" I do is put some stabilizer in the fuel tank although I believe I did not run the engine the first two years to get the "stabilizer" into the engine prior to the winter. Also, I have not topped the tank off prior to the winter like I have heard a few suggest I should have done. Whatever this is it has gotten progressively worse each Spring for the last four years. I have attempted to drain the fuel tank but an anti-siphon lid or something is blocking my polymer tubing from reaching the tank. I know this is long and is a common question but any suggestions for troubleshooting and correcting the problem and advice for winterizing and maintenance?

 

[Fireman431]

Re: 1999 Johnson 150hp Outboard Progressively Worse Starting Problems

There was no mention about the carbs. Did your mechanic check the bowls to see if there is a ton of junk in them? Adjust the floats? It sounds like you have fuel delivery issues.

 

[Solittle]

Re: 1999 Johnson 150hp Outboard Progressively Worse Starting Problems

What do the plugs look like? Compression? Spark - use a testor & spark should jump a 7/8" gap with bright blue snap.

 

[CapnRon]

Re: 1999 Johnson 150hp Outboard Progressively Worse Starting Problems

Well, thanks everybody but it is running great now. After changing fuel pump, filters, plugs, gas, lines, ignition, switches, gas additives, etc. A fellow as novice as I am asked me where the bottom rubber lines near the top and bottom at rear of engine went (plastic air filter to the carbs was removed) and I told him to the air filter. When I was showing him the hole at the top of the filter where I inserted the top line an opening there revealed a hole to "nowhere" and it obviously had no use going there. We looked closer at the carbs and a small outlet needed a line and that is where it went.

I can't believe that a simple vacuum line has caused this much money, trouble, pain and frustration. How I began putting the line on the filter I have no idea but apparently the motor ran OK for some time with it there.