1996 Johnson 50 Not starting

[janul15]

Hello All. Still no joy starting my Johnson 50. Compression good, spark good, woodruff key in place, carburetors have been cleaned, linkages checked. The engine is not firing, even when spraying 'Easy Start' directly into the carbs. Is it worth me inspecting the reed valves (I've only recently heard about them), and do I access them from the carburetor side of the engine? Or is it time to go to a proper mechanic?

 

[Crosbyman]

what happens if you add some fuel in a sparkplug hole say 5-10cc and start theengine... does it have ignition for a few sec.

what is good... compression ?? post eng. mdl

 

[racerone]

How did you check the key?---Explain in detail so you get the answers you need.

 

[janul15]

Compression is 150 psi on both cylinders. Key removed and replaced. I haven't tried putting fuel in the spark plug hole.

 

[saltchuckmatt]

Mechanic seems like the best alternative here since your answers are not detailed enough.

Crosby, good to see and hear from you!

 

[janul15]

Just realised what crosbyman meant . Engine model is Johnson BJ50 BELEDS. Will go to the boat and try the direct fuel into spark plug hole method, likely to be tomorrow.

 

[racerone]

Tried switching plug leads ?-----And 5 to 10cc of fuel is overkill.----5 to 10 drops get a good test result.

 

[janul15]

I did switch plug leads previously, no change. 5-10 drops of fuel to be tried on Saturday

 

[janul15]

Tried putting fuel into spark plug holes 1cc in each, then 5cc in each. Nothing really happened, except a few pops. Will go back and remove/replace Woodruff key (done this a few weeks ago) before I look further

 

[racerone]

Is the key a factory part ?----Hardware store part ?----Did you torque the nut properly ?

 

[janul15]

Thanks Racerone,
Just checked the key is still in place- can't remember the brand, but from a marine parts store, for this model Johnson. Tightened the nut as far as possible, although my torque wrench has broken, so I can't see what the torque is. I'm going to reattach my carbs, replacing one or more studs, nuts and gaskets. Can anyone give the specs of the nuts? Could a poor seal between carb and manifold cause my starting problem?

 

[saltchuckmatt]

Yes, all those things matter....so does starting it. I met gobs of people that start them wrong.

Find a friend that has more knowledge of your outboard or watching YouTube videos. If you have a friend have him come over you guys can have a beer talk about what's correct.

 

[janul15]

I agree with you Saltchuckmatt. I will try to correct any carb/manifold gasket problems, then call a friend, if it still won't start.

 

[racerone]

With a few drops of fuel in cylinders the motor should " roar like a wild lion " -----The flywheel key is there to get correct timing.-----The flywheel taper and crank taper drive the flywheel when torqued to 100 FT LBS.----If tapers are not matched , key may shear again.---Use valve grinding compound to repair / match the tapers.----Assemble with tapers clean and dry.----I have seen key sheared where someone greased the tapers.----Made me chuckle when I found that one in less than 10 minutes of trouble shooting.

 

[janul15]

I was about to call an engineer, when I decided to check a couple of things. My spark gap test suggested a poor spark. Good at 1/16", losing a full spark at 3/16". (I can still see some spark, but not a clear arc across the gap..) Checked the resistance of the spark plug leads; if I'm reading the meter correctly, this shows 1.4 k ohms on each. Could this be a problem? The leads were fitted quite recently, but were not fom a Johnson/Evinrude supplier.

 

[racerone]

Do your new plug wires have a metal core ?

 

[janul15]

Hello Racerone. I've dismantled that plug wire, and have ordered a correctly labelled product. I was surprised to find the core is not metal, but looks like bunched fibres.

 

[racerone]

You may have discovered your issue.----Getting parts from a good dealer is always the best.----Some online sellers will sell you just about anything !!!

 

[Crosbyman]

Hello Racerone. I've dismantled that plug wire, and have ordered a correctly labelled product. I was surprised to find the core is not metal, but looks like bunched fibres.

they are basically carbon fibers mostly used on cars today to reduce static interference which was a pain when AM radio was the big thing. Today with FM 5g Cell etc... carbon fiber wires are likely cheaper that copper strand. Are they needed on cars today ..I don't know.. maybe the extra RF spill would mess things upon fancy car computers. RF is said to "not good" to sensitive EMM on ETECs

By ohms laws you highest voltage drop (AKA spark) will be across the plug gap (infinity ohm wise so a 1.4 Kohm carbon wire is actually so small a value % wise that the "voltage drop" effect in 12 inches of carbon fiber may be minimal for 15-25kvolts .

I am not against metallic wires ...use them all the time but it will be interesting to see the outcome of going from 1.4 kohm wires to 0 ohm wires.

keep us posted !

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[janul15]

Thanks for your feedback. I have now definitely got a good spark (3/8" on spark gap tester). However, I may have been getting that on my previous HT leads, but I couldn't see clearly outdoors, on a bright day. Nothing changed on starting. Fitted new plugs, gapped to Johnson specs. Nothing changed.
Now I'm going back to where I should have started; throw out my old can of fuel, try some absolutely fresh, mixed 50:1. I'll update you soon.