15hp johnson just died

[rosgood14]

I have a 1995 Johnson 15hp that has been running perfect with the exception of a little sputter every now and then. I assumed it was something in the carb. I was out boating on sunday when i took of and after about 10 sec the motor went to spitting and sputtering and then just died and it would not start back up. I brought it home and tore the carb off thinking that something had finally clogged it up, but she was clean as a whistle but i cleaned it anyways. i put it back together and tried to fire it up and it tried to start the first pull and that was it. I checked my fire and i was getting nothing so i was told to check the kill switch/safety kill thingy. I tinkered with it and it fired up, but is running like crap. i attempted to tweak the carb but it made no difference. I decided to check the fire and while it was running i took the top cylinder spark plug wire off and it didnt effect the way the motor was running but it was getting spark. i did the same to the bottom one and the motor would run but it was a lot worse and died shortly after doing so. I checked and i still have compression in the top cylinder so i am at a loss. I could really use some help since i just bought this motor 2 months ago and it is fishing season. thanks

 

[the machinist]

Re: 15hp johnson just died

I think I would replace the spark plugs as a first shot at your problem.

 

[raczekp1]

Re: 15hp johnson just died

hi.
my friend is owning the same model, and i looked how it works.this model also sputter at low to mid range speed.to compare with my 9.9 83' i have to tell my motor works very calm in the same speed range.
i think it becouse compresion unbalance.(i didnt check compresion, its my observation).
so clean the carb, and try compresion test

 

[rosgood14]

Re: 15hp johnson just died

shortly after i was messing with the plugs again the motor was running crappy still and then it just died like it did when i was on the water and i had no fire from either plug for some reason. i am going to try in the morning and see what it does. I have already cleaned the carb and compression is good. i plan on getting some new plugs but i dont see that being the problem since the fire goes in and out

 

[AlTn]

Re: 15hp johnson just died

if this is the 2 stroke model, try unhooking the kill switch wire where it either joins the power pack or if there is a screw connection for the wire to the powerpack, just unscrew the connection and see if the spark returns. If it does, you'll have to kill the motor with the choke or unplug the fuel line and wait for it to run out of fuel.

 

[rosgood14]

Re: 15hp johnson just died

i just tried to disconnect the kill switch but it is wired directly into the wiring harness and i would have to cut it which i dont want to do just yet. i took the coil off and checked all the wires and checked the rest of the wires on the motor and when i put it back together the motor would start again just rough like before. i checked the spark and it is so weak that i can hold my finger on the end of the plug and its just a small shock coming through when i know it should shock the crap out of me. So what are the possibilities. Im thinking coil pack just give me your opinions. thanks for the help.

 

[AlTn]

Re: 15hp johnson just died

can you post a model no.?...I have no knowledge of the 4 stroke version's ignition system

 

[rosgood14]

Re: 15hp johnson just died

J15reo

 

[fireman57]

Re: 15hp johnson just died

If your kill switch has a bare/worn wire it will affect your spark. If you are sure that is it then sounds like a new coil is in order. They are only around 20.00

 

[AlTn]

Re: 15hp johnson just died

does 1 of the 2 wires coming from the kill switch have a ring terminal on it and goes to ground?..if so..unhook that ground wire and , making sure it's not touching the case, see if the spark returns?.. if no change, you can take the kill switch out of the equation. Next up would be to check the ground for the power pack...it should be another ring terminal going to ground...take it off and clean the ground and ring to shiny..if the spark is still weak, but going to both plugs, post back and we'll continue...

 

[rosgood14]

Re: 15hp johnson just died

Ok so i disconnected the ground for the kill switch and nothing changes. I took the ground for the power pack off and cleaned it and still nothing changes. i also went ahead and bought a new coil pack because the old one's back was deteriorating so i knew it couldn't hurt. i also got new plugs. so with all that being said where does that leave us with solutions. thanks for the help guys

 

[AlTn]

Re: 15hp johnson just died

well, if you want to take the guess work out of it, this is where you are at...either buy a dva capable multimeter, purchase a dva adaptor for your multimeter, or build a dva adaptor for your multimeter, then go to cdielectronics.com and use their troubleshooting guide for your ignition. In essence you measure the voltage coming from the powerpack, the voltage going into the powerpack from the charge coil and the triggering voltage going into the powerpack from the sensor. The charge coil and sensor are under the flywheel, so you'll have to get a puller for thaem. Now, you can take a shot in the dark and replace the powerpack and see if that restores your spark. You can see diagrams of your ignition components at marineengine.com, boats.net, shop.evinrude. com. It doesn't sound like your sensor coil is the problem as you are getting spark to each cylinder. I don't know with any certainty if your charge coil can produce a weak current if it's not functioning properly. I know with certainty that the powerpack can produce a no spark to either cylinder, no spark to one cylinder, intermittent spark to both or one depending on temperature.
If you have access to a known good powerpack, I'd suggest replacing it and going from there.

 

[rosgood14]

Re: 15hp johnson just died

ok i will see about finding a good used powerpack but i just found a symptom that boggles me and im not for sure that it has to do with spark or not. when the motor is revved up it runs like crap but i happen to idle it down to the shift zone and the motor went to purring like a kitten and when i gave it full throttle it revved up like its supposed to until it hit top end then went back to running like crap. now i almost think that has to do with the carb but i have cleaned and checked and re-checked the carb and dont think anything is wrong with it. could it still be spark or what.

 

[mikesea]

Re: 15hp johnson just died

does it seem to be running rich,meaning ,you smell gas,might see a lot of crap coming out the exhust,if so,your fuel pump may be passing fue back into the eng.via the pulse port ,it is either on backside of the fuel pump or has a seperate hose depending on year,i cant recall all of them.Also,do not hi rev in neutral

 

[AlTn]

Re: 15hp johnson just died

using an inductive timing light, alternately clamp on to each plugwire and watch the flash. If it doesn't vary in frequency or light intensity as you hit the "runs like crap" zone, then your ignition is doing all it can. If it skips and dims, you still have problems with the ignition.

 

[rosgood14]

Re: 15hp johnson just died

how do i fix this problem with the fuel passing back into the engine because there is a lot of crap in the exhaust and i just replaced the power pack so there is nothing else electrical that can be wrong so i think your idea is sound i just need to know what to do about it. thanks

 

[Mojo^]

Re: 15hp johnson just died

I'm watching this thread intently as I seem to be experiencing a very similar condition on a 25 hp. 2-stroke.

 

[rosgood14]

Re: 15hp johnson just died

does it seem to be running rich,meaning ,you smell gas,might see a lot of crap coming out the exhust,if so,your fuel pump may be passing fue back into the eng.via the pulse port ,it is either on backside of the fuel pump or has a seperate hose depending on year,i cant recall all of them.Also,do not hi rev in neutral

how do i fix this problem with the fuel passing back into the engine because there is a lot of crap in the exhaust and i just replaced the power pack so there is nothing else electrical that can be wrong so i think your idea is sound i just need to know what to do about it. thanks

 

[Cofe]

Re: 15hp johnson just died

The fuel pump is powered by a pulse connection to the lower cylinder. Each time the lower piston moves back and forth, it creates the pulse for the fuel pump. If a fuel pump diaphragm or check valves are damaged, fuel can be sucked into the cylinder through the pulse connection and cause the lower cylinder to flood. Hope you get to fishing soon...

 

[rosgood14]

Re: 15hp johnson just died

where is this fuel pump diaphragm or check valves located and whats it take to replace or repair them. thanks