Hello all, this my first post and will try to keep it short. A little history on the boat and motor. I just bought the the boat (1976 Mark Twain) and motor 1986 125 Force with I believe to to be Prestolite electronic ignition, as a "Divorce Special". Previous owner said the motor runs great, and the boat was registered for current year. I didn't get to here it run because when I bought it, it was early in January and freezing. But at the price I paid for it I figured I'd have plenty of room for any repairs.
The motor runs only on full fast idle and will idle after warming up but will die when put into gear. I started trouble shooting, and this is what I found so far. I have a service manual, but having a little trouble understanding the CDI's and some of the tests.
1) Fuel - Tank has new gas and 50-1 oil mix, lines are clear and primer bulb works and builds up pressure. Fuel filter cleaned and looks good. Carbs are getting fuel.
2) Compression test - Am getting 130 - 132psi on all four cylinders doing a cold engine test with throttle wide open while crancking the motor. I did ground the plug wires before cranking the motor.
3) Spark test - Installed new spark plugs. Put a timing light on each plug and cranked the engine. Only have spark (timing light flashes)on the number one cylinder. With light put on other plugs there is no flash on the timing light.
So a couple of questions, Should I see flash on the other three plugs with timing light?
Will the motor start on just one cylinder?
If number one cylinder fires wouldn't number two fire as well if CDI is good for those two cylinders.
Thanks for any and all help you all can give. Bully
The motor runs only on full fast idle and will idle after warming up but will die when put into gear. I started trouble shooting, and this is what I found so far. I have a service manual, but having a little trouble understanding the CDI's and some of the tests.
1) Fuel - Tank has new gas and 50-1 oil mix, lines are clear and primer bulb works and builds up pressure. Fuel filter cleaned and looks good. Carbs are getting fuel.
2) Compression test - Am getting 130 - 132psi on all four cylinders doing a cold engine test with throttle wide open while crancking the motor. I did ground the plug wires before cranking the motor.
3) Spark test - Installed new spark plugs. Put a timing light on each plug and cranked the engine. Only have spark (timing light flashes)on the number one cylinder. With light put on other plugs there is no flash on the timing light.
So a couple of questions, Should I see flash on the other three plugs with timing light?
Will the motor start on just one cylinder?
If number one cylinder fires wouldn't number two fire as well if CDI is good for those two cylinders.
Thanks for any and all help you all can give. Bully