1976 johnson 9.9 suddenly not starting

[Jmac870]

Hey guys I am new to outboard motors and forums both. I recently bought a johnson 9.9 (10E76G). when I bought the the motor it would barely idle for longer than a few seconds which i attributed the the top coil having 2 large cracks in it , but both cylinders read 95 PSI on compressionn gage so i bought the motor anyways as it was very cheap. A couple weeks ago i replaced the cracked coil with a brand new one and switched out the champion plugs for NGK B7HS and the motor started up ran in the barrel great (from idle.to WOT). Since then the only work iv done on the motor was replacing the gear oil in the lower unit, but today when I put the motor on the barrel i could not get it to start for the life of me and the gas is brand new with outboard mixing oil at 50:1. I checked both plugs for spark again and all was good there can smell gas so fuel must be coming through the line. should my next step be to order a carb repair kit and attempt a repair? What could have changed so drastically in 3 weeks of sitting?

 

[Bosunsmate]

Re: 1976 johnson 9.9 suddenly not starting

Things can crawl into carbs and block them up.
Ground the plug wires and pull the rope a couple of times. Remove the plugs and check they a both getting fuel.
A carb clean/service is a good thing to do with any new to you motor

 

[Bosunsmate]

Re: 1976 johnson 9.9 suddenly not starting

By the way someone will ask next if you tested spark properly, ie that it jumped a 7/16" gap

 

[Jmac870]

Re: 1976 johnson 9.9 suddenly not starting

Cant say i actually measured the gap but did notice the bottom plug does not seem to jump as far as the top (new coil on top) but spark still looks blue

 

[Jmac870]

Re: 1976 johnson 9.9 suddenly not starting

Bear with me here as i am a beginner but to check if the plus is getting fuel when i remove it there should be gas on the plug itself? should also add the motor ran great before even though the bottom plug seemed to not jump far

 

[Bosunsmate]

Re: 1976 johnson 9.9 suddenly not starting

Bear with me here as i am a beginner but to check if the plus is getting fuel when i remove it there should be gas on the plug itself? should also add the motor ran great before even though the bottom plug seemed to not jump far

Yep there should be unburnt fuel on them as since you have removed the leads and grounded them elsewhere the sparks wont fire so fuel should build up on them.
If you can do it while the motor is in a tank of water as you want to keep the water pump lubricated. Also being in a tank will mean that if there is any leak in the cylinders the water could be getting on to the plugs. So what you do is you light the wet plugs with a lighter to check its fuel.

Do this a few times to triple check

The last motor i checked the plugs were wet, we thought it was fuel but the motor still wouldnt start so we tried again and then i tried to light the wet plugs, the wettness didnt burn as they were wet from a actual exhaust plate water leak

 

[Bosunsmate]

Re: 1976 johnson 9.9 suddenly not starting

To get the gap just set two nails 7/16 apart on a bit of wood. Connect one nail to the wire from the coil and put another thick wire from the other nail to the spark plug

 

[Jmac870]

Re: 1976 johnson 9.9 suddenly not starting

Okay thanks i will try both of those tomorrow, feeling a bit dumb for not mentioning this as well but the fuel tank is sitting on the ground and hose running up to the motor a couple feet and the primer bulb does not stay firm when the motor is not running

 

[Bosunsmate]

Re: 1976 johnson 9.9 suddenly not starting

Okay thanks i will try both of those tomorrow, feeling a bit dumb for not mentioning this as well but the fuel tank is sitting on the ground and hose running up to the motor a couple feet and the primer bulb does not stay firm when the motor is not running

Im a bit dumb too as im not sure if that will affect it, it might especially on a worn pump, see if you can put the tank above the motor or at least level.
Primer bulb should stay firm with engine off but its normal when running to get somewhat soft