55hp wont run but a few seconds

I'll go through everything that I know has happened with the motor. The motor is a 1973 55hp single carb magneto engine model #555hf. The motor ran real good last year no problems at all other than the flywheel key being broken. Replaced it. This year I decided to decarb the motor as it had about 125psi each cyl. Now has about 145 each cyl. Every since the decarb many problems have arised. The motor wont idle. I have rebuilt the carbs with no apparent change, just worsened. Half the time, now, I spend more time trying to get the motor to run than trying to tune things. It will run every now and then but by the time I get time to adjust anything it will die again. I have the idle screw on the carb about 1 turn out, as I have tried 1 1/2. I still get the same sputter and die out. Now my starter is fried and I have been using a pull rope. I have found that one magneto coil is weak as the other one brings a bright blue spark but one does not. I recently purchased the seloc manual and I cant seem to follow the linc and sync as it misses my particular motor. There are no timing marks on the flywheel. This year I also purchased a new gas tank, fuel line with the primer bulb, and new gas and oil mix. It just amazes me how much I have tried to help this motor tht it acts like it wanted to run on the old stuff.

Re: 55hp wont run but a few seconds

Are you sparking on both cylinders?

If you have one, or see if you can borrow one.. Get a timing light. Clip the light on a plug wire and see if it's sparking. Try the other wire.

How's your points look? May need to be filed? IF those where moved at all. I found with my '70 55hp they are very temperamental. if the point gap is off just a little bit they chug and don't want to run.

Next if you have the flywheel off, double check the all the wiring. Make sure no wires are cracked or chaffed. Issue my motor was point gap and one condenser was bad. Got it purring like a kitten.

Re: 55hp wont run but a few seconds

Well we cleaned and regapped the points a few weeks ago, with no change on that. My dad says he found water in the gas, maybe this is te problem. Not sure how it got in there unless it was from rain but I still cant figure how.