mag problem?

[guajiro0192]

Hi all
I have a 1975 25hp evinrude ss. After finally getting a recurring fuel problem taken care of (ethanol) I thought all was going to be fine. I tried to start the motor, and got nothing, Had a sticking float. But in the meantime I took off the flywheel and tried to adjust the points and plugs. The motor would not start. Then once in a while would "lock up" as I pulled on the rope. It then once in a while would backfire. I thought that it was way too advanced, so I tried to adjust the points again. took the plugs out again and adjusted. I had a very week spark, then no spark! I bought a plug tester and still no spark.
The ?
How can I tell if the magneto is faulty? Do I need a meter? This motor is my nightmare? Trying to just get it to run and plane my 10ft zodiak. After that, I hope I throw a rod through the block and cowl. At that point it will act as an artificial reef! But at least it ran. }:-]

 

[oldcatamount]

Re: mag problem?

Remove the flywheel, screw the nut back onto the crankshaft (finger tight), take a wrench and turn the nut clockwise (which will turn the crankshaft)until the lobe (high side) of the ignition cam is lined up exactly with the cam follower on that particular set of points. That set of points should be open (at this time) and set at .020. Adjust by loosing the retaining screw and turning the adjustment screw slowly. Re-tighten the points retaining screw and repeat this procedure with the other set of points. When re-installing the Woodruff key (half moon shaped key in crankshaft slot), be sure it's parallel with the crankshaft itself (not the taper)and the small hash mark is on the bottom side. Be careful re-installing flywheel and don't disturb the key. Make certain you use a torque wrench set at 40 foot pounds when tightening the flywheel nut. There is a procedure to "fine tune" the points but, setting them at .020 is a ballpark setting and should get you running.

 

[guajiro0192]

Re: mag problem?

Thanks for advice. I found out one of the issues. The ground had come loose. so I am back to the backfire issue. I was able to get spark then , put everything back. It backfired. Should I tune the points at the high end of the cam, or as soon as the cam lifts the points? Another ? that I have is where do I set the stop on the throttle handle?

 

[oldcatamount]

Re: mag problem?

Set the ponts at the high end of the cam lobe. (look closely at the cam, it may have a small "set" area stamped into it. If it does, use that spot to set the points). Set the throttle to wide open position. (not certain it really matters much). Glad you found the loose ground connection, something like that can give you fits.

 

[guajiro0192]

Re: mag problem?

Thanks, i will try that. Could the points be the reason for the backfiring?

 

[F_R]

Re: mag problem?

90% of backfiring problems are because the spark plug wires are swapped.

It could be the points' setting if they are grossly, way off. But like I said---spark plug wires.

EDIT: Starting position on the throttle is put shift in neutral, then open throttle toward "fast" as far as it will go (it won't go very far in neutral).

 

[guajiro0192]

Re: mag problem?

do you mean the wires that go to the coils or the ones to the plugs. The coils are lined up one on-top of the others. I will try the connectors.
The throttle seams to advance pretty far in neutral. I am SURE that I adjusted the control wrong.
Thanks for the info.

 

[guajiro0192]

Re: mag problem?

Well i took the advice and guess what? I was right in that I was wrong. Thank you. I switched the wires and it cranked up. A lil flooded but it kicked out the raw gas with a lil throttle. I went to crank it again, and of course was handed my next repair. i sheared the key! I guess that I did not tighten down the flywheel enough. I forgot in reality since I was caught up in the moment. The biggest drawback that this motor has is that the flywheel threads for the nut are crossed about halfway down the shaft. Hardened steel is a little difficult to rethread. If anyone has an Idea, please let me know. This is how I bought the motor. $100 was too little to give up!