1972 40hp Johnson OB issues

[KaiBlaed]

2cyl 2 stroke. Magneto. I am having intermittent problems. I cleaned all the crud out of the carb, replaced the needle, float, and gasket. Cleaned everything out, its spotless now and all the tubes are cleared. I bought new spark plugs. Gapped them to .30. After all that the engine was trying to start, wasnt getting very good spark... Pulled the flywheel, cleaned off the points and adjusted them to .020. I had it running great one night, ran for about 20min. The next morning it wouldnt start and I wasnt getting spark to the top cylinder. Checked the points and one had widened, so I adjusted again. Then the engine runs but spits and sputters the whole time. So I adjusted the points again, and adjusted the high flow needle.... nothing ... The control box for the throttle wasnt working to open the engine all the way up after it was running so I adjusted the cable and then it ran great at higher rpms .... I idled it down too far and it died and now it will not even attempt to start. now I'm sometimes getting spark .. sometimes not .... I've adjusted everything over and over ... I get spark when testing it but it doesnt even try to start. Could there be something that is causing the engine to not start after it has warmed up?

 

[tx1961whaler]

Re: 1972 40hp Johnson OB issues

Look for (2) black wires coming out from under the magneto. These are the kill wires for the motor. Disconnect them and see if the problem goes away. Note that you will have to use the choke to kill the engine after disconnecting the wires. If it does fix the problem, then there is an intermittent short someplace.

 

[phipps]

Re: 1972 40hp Johnson OB issues

Not sure if this applies, but the points on '71 60hp are supposed to be set to .010.

Does that engine have an amplifier?

 

[KaiBlaed]

Re: 1972 40hp Johnson OB issues

I have no idea .... I'm very new to working on outboards ... i need to get a manual here soon. On top of the flywheel it says .020 so that is what i set the points to.

 

[tx1961whaler]

Re: 1972 40hp Johnson OB issues

Not sure if this applies, but the points on '71 60hp are supposed to be set to .010.

Does that engine have an amplifier?

No, the 40 HP is set to 0.020
No, a 1972 40 HP has no amplifier

 

[phipps]

Re: 1972 40hp Johnson OB issues

I have no idea .... I'm very new to working on outboards ... i need to get a manual here soon. On top of the flywheel it says .020 so that is what i set the points to.

Definately get a manual, factory manual if possible. I am working on getting a 71 60hp running and the factory manual has been invaluable to me.

 

[KaiBlaed]

Re: 1972 40hp Johnson OB issues

This boat gonna drive me crazy .... cant figure it out now. It's never the same plug not gettin spark ... sometimes neither does ... sometimes it seems like its not getting fuel. I'm bout ready to sell it. I got so frustrated with it today that I decided to hook up the lights for the boat and trailer and I put in a cd player and speakers. Electrical is fun. Engines just not my thing