4hp Johnson help please!!!

[Tnpipewelder]

Hello, I have acquired an 87 Johnson 4hp motor. It is all there just hasnt been ran in a long time. It will not start, spit, sputter backfire or anything else. Checked the compression, both cylinders were 82/83psi. Checked spark with spark tester it jump adequate fire. Carb has been cleaned and looked over and all appeared to be good. Any help or opinions would be be appreciated.

 

[hardwater fisherman]

What is the model number? Does it have the fuel tank on top of the motor? Or an external fuel tank?

 

[Tnpipewelder]

J4rdhcud, external tank.

 

[hardwater fisherman]

What is your starting procedure? Spray a little mixed fuel into the carb throat and see if it pops.

 

[Crosbyman]

you have compression... you have sparks...you have oxygen and... you need fuel

have to clean the carb ? ..correctly

disconnect to fuel to carb inlet and pump the pump... is it flowing out the hose?
can you see if the carb fills up or not .. if not sticky inlet needle or float misaligned

what happens if you spray....some carb cleaner in the carb while you rope start it does it sputter ?

 

[oldboat1]

Believe you should measure at least 3/8 inch spark. Test with both plugs removed. If spark checks out, clean and regap plugs -- eg. Champion L86C gapped at .030.

 

[Tnpipewelder]

Ive done all the above, it will not even try to start from sprayin fuel, carb cleaner or ether in carb.

 

[hardwater fisherman]

If you have a kill switch with a lanyard. Make sure the lanyard is installed correctly.

 

[racerone]

Flywheel key ??---Plug wires reversed ?----Crankcase compression ?

 

[Tnpipewelder]

Being u familiar with motor, i have swapped ug wires back and forth. Multie times and still nothing. Flywheel key is good. Im absolutely puzzled here.

 

[racerone]

" good spark " means nothing here.----Does spark jump an actual gap of 1/4" ( 7 mm ) on this motor , yes or no ?

 

[Tnpipewelder]

Miraculously third day on this thing. It just started actin right. Not sure what happened to make it change its mind. Thanks for all the helpful suggestions. Thank you all!!!!

 

[Tnpipewelder]

Yes , my term of "adequate spark" meant it met spec....

 

[oldboat1]

livin' righteous... Maybe your plug boots weren't fully seated on the plugs -- good on the tester, not on the plugs(?)

Anyway -- Good boating!