90 Hp Power issues

90 Merc Outboard 1989 ? I started having an issue of the motor shutting down after running full throttle for a few minutes. I found that the primer bulb was not staying full and a cracked 3inch line. I think it was a vacuum line. I replace the fuel line to and from the primer , the cracked line, and decided to put in new plugs. When I started it I got a few good backfire pops, something new, but then it started and continued to pop every now n then.
I took it out and it now stays running but I don?t have any power at full throttle and idle is ruff. Could the pops I had when I first started it, have caused the coils to go. I know a bad coil can cause some issues, but not sure what.
Thanks
Back yard mechanic

Re: 90 Hp Power issues

The "decided to put in new plugs" may be a clue. Did you put in the same type? Do you still have the old ones such that you can reinstall them for a comparison? Popping is definitely ignition so the hoses aren't your problem.

When you pulled the caps off the plugs, were you very careful with the boots and wiring to the CDMs? Did you get all your caps back on and pushed down all the way? Obviously you got all caps on the correct plugs.

The new plugs could have allowed more current out of your CDM and that may have burned out a part that was marginal but could operate the old plugs.

Loss of power says you may have indeed smoked a CDM. To Check, disconnect the input wiring, not the spark plug cap, to one CDM at a time, crank her up and get some data. If you can pull one and your performance doesn't change then you have your smoking gun.

Run all the tests and get back.
Mark

Re: 90 Hp Power issues

Plug wires are wrong.

Re: 90 Hp Power issues

Thanks for the quick response. I think I do have the old ones to try. Will double check connections again also.