1970 Johnson 20 hp 20R70C Outboard Motor started then can't get it to start..

[noob_boater]

Before i bought the motor, the previous owner started with just 3 pulls. Killed it..several minutes later, started it up fine..

Took it out on lake and managed to start the motor and it ran super fine. Here comes the problem. After an hour or so, i decided to unplug the gas line to the motor (previous owner said to unplug it if not used for a while since fuel make flood motor).

After a half of day fishing, plugged fuel line back in, primed the gas ball till it was stiff. Pulled and pulled, and pulled and nothing. You can hear the sound of the spark or whatever you call when pulling. After about 30 pulls, no sound. Took plugs out and they were wet and tips were very black. Bought new plugs (NGK vs old Champions).. Plug sound comes back, but still nothing. new plug tips were slightly dark. Fuel is leaking from throttle plate.

I totally flooded the motor huh? I'm a complete noob with boat motors. I'm not a carb guy either. Have never owned nay carb operated vehicle.

any tips? i read about 3-4 hours worth of material on here, but wanted more tips before tearing the motor apart.

 

[Daviet]

Re: 1970 Johnson 20 hp 20R70C Outboard Motor started then can't get it to start..

Have you checked the spark, needs to jump a 1/4" air gap and be bright blue. You should put champion plugs back in your engine.

 

[ultra353]

Re: 1970 Johnson 20 hp 20R70C Outboard Motor started then can't get it to start..

You don`t have to unhook the fuel line when your out for the day. Most likely your needle and seat are a bit worn which is letting fuel get by thus flooding your motor. Once fuel fills the bowl when you pump the primer ball the fuel pump takes over when the motor is started. When you rehooked the fuel line and pumped it up again it might have pushed fuel past the needle/seat and flooded it. Carb work is fairly easy, unbolting it is probably tougher, Lol . Let us know if you need help.
Double check your spark first like Daviet said to eliminate any electrical issues, then move onto the carb/fuel system..

 

[noob_boater]

Re: 1970 Johnson 20 hp 20R70C Outboard Motor started then can't get it to start..

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part #30. Needle valve. what's it suppose to be at? it was turned all the way in. Seems to me, it's the air/fuel ratio adjusting button. The previous disconnected it..

i just took of the lower end of the drawing and all the holes seem free of clogs. Gotta take the upper part off now. I also realized the pistons are a bit black when viewing from spark plug hole..

Gonna test if there's spark... brb..

 

[noob_boater]

Re: 1970 Johnson 20 hp 20R70C Outboard Motor started then can't get it to start..

part #30. Needle valve. what's it suppose to be at? it was turned all the way in. Seems to me, it's the air/fuel ratio adjusting button. The previous disconnected it..

i just took of the lower end of the drawing and all the holes seem free of clogs. Gotta take the upper part off now. I also realized the pistons are a bit black when viewing from spark plug hole..

Gonna test if there's spark... brb..

 

[Daviet]

Re: 1970 Johnson 20 hp 20R70C Outboard Motor started then can't get it to start..

That is the low speed needle valve, ststic setting is 1 1/4 turn out from lightly seated, and fine tuned in the water in gear. Sounds like it's time to overhaul the carb, make sure you remove the core plug (#5) on top of the carb and clean the passages in there.

 

[noob_boater]

Re: 1970 Johnson 20 hp 20R70C Outboard Motor started then can't get it to start..

first timer... i unplugged the spark plugs.. tested one at a time. Wrapped a 16 gauge wire around the neck of the plug and grounded to the block..

pulled a couple times and i didn't see any sparks.. Or did i do something wrong? Does it have to be properly grounded to see sparks?

thanks.. will have to look at #5

 

[Daviet]

Re: 1970 Johnson 20 hp 20R70C Outboard Motor started then can't get it to start..

You have to check the spark coming out of the plug boot to the block. Pull the plugs and the engine will be easier to pull over.

 

[noob_boater]

Re: 1970 Johnson 20 hp 20R70C Outboard Motor started then can't get it to start..

so there is indeed spark. couldn't really see it when i tested, but after several pulls, the tip of the plug is blue'ish. Motor still won't start. prime bulb is firm with no leaks. Fuel is slightly leaking out of the choke/throttle plate. What does that mean? I checked all the carb holes and liquid passes through them easily..

is fuel not getting into the cylinders? i sprayed a little bit of fuel int there via spark plug hole, but no luck again. Should i spray more fuel directly in there?

 

[noob_boater]

Re: 1970 Johnson 20 hp 20R70C Outboard Motor started then can't get it to start..

what is this little line for and could that leak be a cause? yeh, i was in "N" when trying to start it.