1986 50hp johnson troubles

[rockychad]

Hey guys- im hoping to pick the brains of any one with experience with this outboard. Heres the story so far, ive had it a few years never used it a great deal but never had any issues with it, i recently moved and didnt get a chance to run it up for a few months. Thursday last week i decided to give her a run and she started and ran with no worries at all, come saturday morning and i cant get her to start, in fact ive tinkered with it every day between then and now and still dont have any progress! So this is what ive done so far;
-Ditched the fuel and replaced with new,
-drained and Sprayed carby cleaner in the carbs, removed the top carb as its much easier to look at and it was spotless.
-Checked spark and it appears good, even replaced spark plugs.
-i damaged one of the spark leads during my investigation but have since fixed it and tested for continuity-all good.
-I compression tested the cylinders, top 85 psi and bott 90 psi which seems low to me but i dont have a manual to check it against.
-Ive put aerostart in it several times and have put fuel in through the spark plug holes afew times aswell, cant get it to fire at all.
-with the spark plugs out ive turned it over and it appears to have a mist coming out so i believe fuel is coming through good.
-also took the hose of the top of what i assume is the fuel pump when not running, when i squeeze the fuel bulb i get fuel there.

So my conclusions are Fuel is good and spark is good. Im thinking the timing may be out, ive heard about the flywheel woodruff key can shear throwing the timing out or that compression is my issue.

Any thoughts guys as its becoming a real pain. Thanks in advance for your responses.

Oh yeah ive cleaned and tightened battery terminals, and have been alternating between 2 batteries and always charging the out of use one overnight.

 

[racerone]

Re: 1986 50hp johnson troubles

If it cranks slow there will not be any spark from the magneto.-------Checking flywheel key is a good idea.---Make sure you torque the nut to 100 FT-LBS after.

 

[rockychad]

Re: 1986 50hp johnson troubles

If it cranks slow there will not be any spark from the magneto.-------Checking flywheel key is a good idea.---Make sure you torque the nut to 100 FT-LBS after.

Cheers mate- Im pretty sure cranking speed is good, definately getting a spark anyway when i pull the plugs out and rest them against the block when cranking. will pull the flywheel tonight or tomorrow- i had a crack at it the other day but couldnt hold the flywheel in situ when trying to undo the nut, got to improvise a way with what ive got.

 

[Bosunsmate]

Re: 1986 50hp johnson troubles

Cheers mate- Im pretty sure cranking speed is good, definately getting a spark anyway when i pull the plugs out and rest them against the block when cranking. will pull the flywheel tonight or tomorrow- i had a crack at it the other day but couldnt hold the flywheel in situ when trying to undo the nut, got to improvise a way with what ive got.

I put a soft rope into the top cylinder so as it compresses it the motor doesnt turn and the nut should loosen. With the nut off you may be able to see where the groove for the top of the flywheel key is to save you pulling the flywheel off too

 

[rockychad]

Re: 1986 50hp johnson troubles

I put a soft rope into the top cylinder so as it compresses it the motor doesnt turn and the nut should loosen. With the nut off you may be able to see where the groove for the top of the flywheel key is to save you pulling the flywheel off too

Thanks mate, thats a good idea, ill give a try tomorrow.

 

[rockychad]

Re: 1986 50hp johnson troubles

Didnt get very far with the flywheel today, got the top nut off but couldnt remove the flywheel its self, i bought a puller but havent been able to match the thread of the three holes in the flywheel yet(any one know off the top of their head???). I started checking a few other things in the interim- one thing i noticed was the wires that go from the powerpack to each coil are damaged- one is slightly burnt looking whilst the other has a bit of melted insulation- now i am getting spark so is it something to worry about?? I also had a look at the choke/enricher- i believe that when i hold the key pushed into the ignition that it activates the enricher-is that right??? When i hold the key all the way in it does not appear to do anything ie no audible noise/sound/click- how ever if i run an electric cable from the pos of the battery to the pos of the enricher i get an audible click as if some thing is happening- now im assuming this enricher isnt working properly, i dont however think this is my main problem though as i said earlier i have put fuel directly into the cylinders and tried aerostart and cant get it to pop at all. And lastly is anyone able to confirm whether 85/90 psi is poor compression- ive done a bit of research but get varying info. Thanks for your help guys.

 

[rockychad]

Re: 1986 50hp johnson troubles

I put a soft rope into the top cylinder so as it compresses it the motor doesnt turn and the nut should loosen. With the nut off you may be able to see where the groove for the top of the flywheel key is to save you pulling the flywheel off too

Thanks bosunsmate-rope in the cylinder worked a treat.

 

[rockychad]

Re: 1986 50hp johnson troubles

Oh i forgot to mention in regards to the dodgy wiring out of the powerpack that i measured the resistance between the end of the spark leads and the block and got about 4 k ohms which i believe is good and further supports my theory that the dodgy looking wire isnt an immediate issue.

Cheers guys.

 

[Bosunsmate]

Re: 1986 50hp johnson troubles

Yep something sounds faulty with your choke wiring. You will need to trace that back to the controls to figure out where its snapped etc.
continuousWave: Whaler: Reference: Ignition Switch

Your compression i think is ok, it should definitely start with tha no problem.
The melted insulation indicates it has overheated at some time. Sounds like no problem though as you are still getting spark.
I think you should hook up a switch to the solenoid so you can operate that remotely while you do the rest of your trouble shooting as using the choke solenoid is so much more effective than spraying into the carbs.

Also try starting it but have the lanyardline disconnected or the Ht leads grounded elsewhere so that the sparks arent firing. On the fourth go then pull out the plugs which should be then wet with fuel. Try lighting that to check it burns.
What you are checking for is if there is any water in the system that is whats coming out of the cylinders in that mist you see.
You need to crank it a few times to make sure the motors cooling channels are filled with water first.

If that wetness catches fire then id concentrate on spark and timing still.
Not sure about the thread for the puller, make sure you thread in a lot but not to dar in as you can end up screwing into the stator

 

[rockychad]

Re: 1986 50hp johnson troubles

Yep something sounds faulty with your choke wiring. You will need to trace that back to the controls to figure out where its snapped etc.
continuousWave: Whaler: Reference: Ignition Switch

Your compression i think is ok, it should definitely start with tha no problem.
The melted insulation indicates it has overheated at some time. Sounds like no problem though as you are still getting spark.
I think you should hook up a switch to the solenoid so you can operate that remotely while you do the rest of your trouble shooting as using the choke solenoid is so much more effective than spraying into the carbs.

Also try starting it but have the lanyardline disconnected or the Ht leads grounded elsewhere so that the sparks arent firing. On the fourth go then pull out the plugs which should be then wet with fuel. Try lighting that to check it burns.
What you are checking for is if there is any water in the system that is whats coming out of the cylinders in that mist you see.
You need to crank it a few times to make sure the motors cooling channels are filled with water first.

If that wetness catches fire then id concentrate on spark and timing still.
Not sure about the thread for the puller, make sure you thread in a lot but not to dar in as you can end up screwing into the stator

Thanks again bosunsmate- really appreciate your help. Im out of town most of this week so will try as you suggested when i return.

Cheers

 

[racerone]

Re: 1986 50hp johnson troubles

???----5/16" -NF is the thread.

 

[rockychad]

Re: 1986 50hp johnson troubles

???----5/16" -NF is the thread.

Thanks mate.