40 HP wont start

[hburtonr]

Hi everyone,
i have just aquired a johnson 40 hp, i think its quite old, it is green in colour, someone says it is ex forces, i have pumped fuel through and put new spark plugs in but willo not fire up, it is a manual pull start, how do i check for a spark ? do i remove the plug and leave it resting against the block and try and pull start it ? i will try and get the serial numbers from it
any info would be great
richard

 

[tx1961whaler]

Re: 40 HP wont start

First thing:
Post the model number and serial number. They are found on the plate that is mounted to the transom clamp.

Next thing to do is run a compression check on the cylinders (you need a screw in compression tester for this) to see if they are +/- 10 % of each other. This will tell you if it's even worth spending time fixing this motor. You can usually get a loaner from the auto parts store. Post your findings when you do this.

If the compression is OK, then check the spark using a spark tester. The spark tester is about 8 bucks at the auto parts store.

 

[F_R]

Re: 40 HP wont start

40hp Johnsons were green in '67 and '68 according to my memory. That does not make them military.

 

[hburtonr]

Re: 40 HP wont start

hi again i think i have the serial No from the Transom mount itis 40RL90AM
the No underneath is C 35 620
hope this helps
many thanks

 

[tashasdaddy]

Re: 40 HP wont start

this are what i came up with for the 40 RL

http://www.outboardbooks.com/index.cfm?fuseaction=items.main&boat=JM Outboard Motors&orderby=model
40 1969 40RL69
40 1970 40RL70
40 1971 40RL71
40 1972 40RL72
40 1973 40RL73
40 1974 40RL74
40 1975 40RL75
40 1976 40RL76

seeing it is a recoil start you need a helper to check spark, like this. connect to spark plug wire and to spark plug.

 

[hburtonr]

Re: 40 HP wont start

Thanks Tashasdaddy you're right it is a 1970 40RL70AM, i have checked and there is no spark, but what i've noticed is a little black wire hanging loose, it looks like it should be fastened under the fly wheel, it looks like the remainder of a spade clip under there, should there be a black wire coming from under the fly wheel ?
i am going to solder it on tomorrow and see what happens
once again thanks to everyone

 

[tashasdaddy]

Re: 40 HP wont start

that would be a kill wire, someone probably pulled it loose trying to get spark. that age motor it is very common for the coils to be cracked and bad. it requires pulling the flywheel.

PULLING FLYWHEEL

you need a harmonic balancer puller, you need 3 - #8 harden bolts, that fit the 3 holes in your flywheel. standard hardware store bolts will strip out, causing more problems. loosen the flywheel nut, leaving it on so it protects the thread. thread the bolts in 7/16 of an inch. then tighten the puller, adjust so it has a straight pull. now tighten the puller, rap the center bolt with a hammer, then tighten some more. you may have to let it sit over nite, and repeat in the morning. this is a compression fitting, it will eventually POP!!. do not loose the woodruff key that goes in the groove of the flywheel and the crank shaft. then installing the flywheel, it has to be totally clean, no oil, woodruff key in place. then torque the nut to the specifications for your particular motor. if you do not do this, the woodruff key with shear, and you will be repeating these steps.


you will probably find bad coils, you can completely rebuild the ignition, carbs and water pump for about $200. and have a reliable motor.

this is a really bad case, what happens when a wire gets crossed and 12 volts go to the coils.

 

[hburtonr]

Re: 40 HP wont start

Thanks for the pics Tashasdaddy, great help, one of the coils has definately burnt out its completely black, but i didn't get a spark from the other cylinder so i guess that ones shot too so i will have to try and get a couple of coils from a breakers or something (not too many over here in uk), will keep you informed cheers

 

[tashasdaddy]

Re: 40 HP wont start

you have a private message.

 

[coolguy147]

Re: 40 HP wont start

that would be a kill wire, someone probably pulled it loose trying to get spark. that age motor it is very common for the coils to be cracked and bad. it requires pulling the flywheel.

PULLING FLYWHEEL

you need a harmonic balancer puller, you need 3 - #8 harden bolts, that fit the 3 holes in your flywheel. standard hardware store bolts will strip out, causing more problems. loosen the flywheel nut, leaving it on so it protects the thread. thread the bolts in 7/16 of an inch. then tighten the puller, adjust so it has a straight pull. now tighten the puller, rap the center bolt with a hammer, then tighten some more. you may have to let it sit over nite, and repeat in the morning. this is a compression fitting, it will eventually POP!!. do not loose the woodruff key that goes in the groove of the flywheel and the crank shaft. then installing the flywheel, it has to be totally clean, no oil, woodruff key in place. then torque the nut to the specifications for your particular motor. if you do not do this, the woodruff key with shear, and you will be repeating these steps.


you will probably find bad coils, you can completely rebuild the ignition, carbs and water pump for about $200. and have a reliable motor.

this is a really bad case, what happens when a wire gets crossed and 12 volts go to the coils.

holy crap that is one bad coil!!!!! lol when i replaced mine they were redone sometime ago and were new. the color of purple i believe but they had a melting mark where the kill switch wires gone under them. i replaced everything under there so i would have to maybe adjust the points for another 10 years and maybe 20 years if u keep it running

 

[samo_ott]

Re: 40 HP wont start

Coolguy, that is what happens when one errantly connects 12v to the coil, as opposed to when they naturally wear out and fall apart.

 

[hburtonr]

Re: 40 HP wont start

Hi Every one
thanks for the info up to now, been spot on, i replaced the coils,points and condensers and after half an hour pulling it eventually fired up it ran a bit lumpy and had to be revved a little but i couldnt see it pumping water out anywhere and after a couple of hours stopping and starting the barrell of water had quite an oil slick on top, i took the front cover off to see where the water would spit out but no pee holes or pipes any ideas....does this motor have an underwater exhaust and water outlet
many thanks
Richard