1996 Johnson 50. Not starting, backfiring only. Primer issue

[janul15]

I've still not got it right. Here's a recap; . Found various problems, and fixed them. But still not firing up. Compression good (150psi on both cyl.). Spark gap test good on both. Spark seen at both spark plugs. Flywheel key good and in place. Spark control rod set at correct spec. (2 1/2"). Sprayed Seafoam into carburettors, fuel is now seen coming from both cylinders. Using new clean fuel, premixed 50:1. One curious issue; when I push in the primer switch, I seem to lose a lot of power to the starter. Carburettors removed, cleaned and replaced. Primer problem still happening.( the engine stops cranking when the primer is engaged) Engine backfires a lot (lots of loud pops), won't start up.

 

[racerone]

Wire from powerpack to coils correct??----Orange / blue stripe must go to top coil.

 

[janul15]

It was correct. Swapped the wires over briefly, but didn't notice the backfire, but definitely not starting. By the way, the problems occur when I try and run on fuel, and also when I spray 'Easy Start' into the carburettor inlet. Apart from the flywheel key, which I've checked several times recently, and the spark control rod, which is set to the specified length 2.5 ", can anything else be causing a serious timing issue?

 

[tphoyt]

I have to ask
Are you removing the flywheel to check the key?
You cant tell just by removing the nut.

 

[janul15]

Yes , but I'll check again. Is there anything else to look at when I take the flywheel off, which might be causing this total non-start/backfire?

 

[racerone]

Operating the wee electric primer valve should not change the way the big starter operates.------So I would look at all the wiring.----On the ignition switch.----Inside the control box.----Inside the wiring harness .---Around the motor.----Something is WRONG there.

 

[janul15]

Agreed Racerone. I'll start with the ignition switch, the barrel may have rotated out of position causing incorrect contacts.

 

[janul15]

Ordered a new ignition switch- original brand, not an aftermarket copy, because I haven't been happy with those. I will fit later this week. I still expect to find a major timing error, so if I need to, it's off with the flywheel again, and go from there.

 

[janul15]

Changed the keyswitch. Still the (primer) electrical problem. Now something's got worse- the starter motor keeps running, regardless of key switch position. I have to remove a battery lead to stop it. Must check all the wiring, but any guidance as to where the problem might have occurred?

 

[Crosbyman]

STARTER RUNS BECAUSE... IT IS GETTING POWER B+ AND THAT NORMALLY COMES FROM THE SOLENOID. IF POWER IS CONSTANT AND DRIVES THE STARTER THE INSIDE CONTACTS IN THE SOLENID HAVE WELDED CLOSED OR.... THE SOLENOID IS BEING TOLD TO POWER THE STARTER BECAUSE THE KEY SWITCH "S" POST IS ACTIVE .

NOT MUCH ELSE CAN GO WRONG

sorry for caps I am not retyping this.

 

[janul15]

Thanks. It may be the solenoid gone bad. It can't be the keyswitch, because the starter runs even when the keyswitch is unplugged at the harness connector.

 

[Crosbyman]

just disconnect the starter control post wire from the switch ... if starter stops solenoid is ok and that wire is picking up +12 battery ..somewhere between the "unplugged" switch and the solenoid.

the control wire may come via an interrupt switch so just work backwards to the unplugged switch

 

[janul15]

Thanks. Replaced the solenoid and cleaned up all the harness connectors. Now the electrics appear good. Still no start, but a backfire. Flywheel key is good. Flywheel nut secured to specified torque. I want to do the timing and synchronisation, but the manual shows that it would be beyond me. Any simplified method just to get it started. ( Maybe I will go to a mechanic)

 

[racerone]

Hurry to a shop.------Post an update once motor is fixed.

 

[saltchuckmatt]

Thanks. Replaced the solenoid and cleaned up all the harness connectors. Now the electrics appear good. Still no start, but a backfire. Flywheel key is good. Flywheel nut secured to specified torque. I want to do the timing and synchronisation, but the manual shows that it would be beyond me. Any simplified method just to get it started. ( Maybe I will go to a mechanic)

I would triple check the coil wires from the power pack to the coils.

Orange/blue (sky) top coil orange/green (grass) bottom coil. 9 out of 10 times on here that is what's wrong when someone posts the scenario you describe.

 

[cdavy000]

Is it backfiring out of the carberator or the exhaust if it’s out if carb it’s too lean “not enough fuel” if it’s exhaust it’s too rich “too much fuel” either way your combustion is off and if you haven’t messed with idle speed, mixture, or choke setting its most likely a timing issue.