1990 50 hp johnson wont start

[PT_ Boater]

Have a 1990 60 hp Johnson that started fine on the lake for about 15 min then cut out and wouldn't start back. Never had any issues prior. Started checking it out and found I hand intermittent spark between the 3 plugs. Assumed the power pack so I ordered a new power pack, 3 coils, 3 plugs and 3 plug wires. Put it all in and unit turns over but will not start. I have fully cleaned the carbs, verified good gas, and have gas on the plugs. What's missing? Rectifier only converts to charge the battery. Even a marine mechanic started it was more than likely the power pack. Any and all help is appreciated.

 

[PT_ Boater]

Update. I have strong solid spark and fuel misting from heads. Everything for combustion but it still wont start.

 

[racerone]

Checked the flywheel key??

 

[boobie]

What's the compression on it ??

 

[oldboat1]

Check spark with an adjustable tester -- should see a consistently sharp half inch, or thereabouts, on each lead.

 

[PT_ Boater]

I have ordered a compression tester and went ahead and ordered carb rebuilt kits also. Tested the fuel today an confirmed fuel is good. Plan on soaking and rebuilding the carbs when the kits come in, connecting an external tank with different gas and making a spark tester to verifiy good spark ( should be great with the new coils, power pack, plugs and plug wires). Tried to start it today with misting gas/oil mix direct in the intake manifold still no start. Flywheel key should be good as everything is turning and sparking as it should. Ill get back with my findings after I get the tester an dthe carbs rebuilt. Been lucky that these parts aren't to costly

 

[oldboat1]

got a timing issue if the flywheel has slipped on the shaft (shears the key) -- happens if torque is too light. (May have spark, but no start.)

adjustable spark testers are $10 or so an auto parts stores if you decide not to make one.

 

[racerone]

Folks are often in the dark about the purpose of the flywheel key !-----A sheared key will give you great spark , just not at the right time !!

 

[PT_ Boater]

Compression is 100psi on all 3 cylinders. Just got carb rebuild kits and bout to get the spark tester. Now just a matter of getting the time to work on it. Hope to get back at it over the week end. I'll pull the flywheel while carbs are soaking to check the key and all.

 

[PT_ Boater]

Ok so I'm at a loss. Soaked, cleaned and rebuilt all 3 carbs. Verified strong spark on all coils. Plugs smell of fuel. Flywheel key good, flywheel in correct spot for tdc etc. Tried spritzing fuel direct in intake manifold on all 3 carbs. Tried different fuel, line and tank. Compression is 100 psi all heads, new coils, new power pack, new plugs,correct gap,new plug wires, carbs fully rebuilt, solid spark and good fuel. I'm at a loss. Looks li K I'm going to have to take it to a shop. Only good thing is I only spent $250 on all those parts so I can't get hit with triple that price from the shop trying to install those parts.

 

[oldboat1]

When you measured spark, what did you get?

 

[PT_ Boater]

Update! After taking to the shop the cause was the stator was causing a dead short to the rectifier killing the high energy spark. Which is why I only got about 1/4" jump on my spark. The shop ended up burning up a second rectifier while checking everything out. So new stator and rectifier and we are good as new! Thanks again for all the help!