454 mercruiser missing, lack of power

[cschauerj]

I writing in regards to a recent problem with my '97 232 Baja w/454. The boat sounds almost as if the engine is missing, and suffers from a loss of power. Two days prior I had the boat out and it ran beatifully. No problems whatsoever. The only thing I can think is that when I hosed the motor off Fri. I got something wet that should not have been. Two days later(Sunday) I suspected this and opened the distributor hoping to find water. No luck. I checked the plugs wires and everything looks tight. Through the course of the day it began to run stronger and stronger but never as good as it should have. It's got a new fuel pump and filter and the plugs were changed within the last ten hours. Like I said, the problem seemed to arise overnight. Is something still wet in the ignition, or did my fuel pickup clog with debris maybe? Any ideas? I appreciate any suggestions!

 

[12Footer]

Re: 454 mercruiser missing, lack of power

The only thing I can think of, is the distributor got trashed by having moisture in it. It may be dry now, but high voltage with no place to go (from water) will try to find another path. This can cause carbon paths to form where it finds that path. This can happen to the porscelin (sp) of the plugs ,or the plug wires too, in rare cases. But change-out the distributor and rotor,and it should return to it's old bad-to-the-bone self. But if you have the oportunity, run the engine on a very dark night. If there is any arc-over at the plugs,plug wires, or the outside of the distrib cap, you will see it.

 

[cschauerj]

Re: 454 mercruiser missing, lack of power

Thanks for the info 12footer. I replaced the cap and rotor today as well as checked the fuel filter for water and inspected all the plugs. I got it on the water and it ran like a champ. That is for about five minutes. Then it died altogether. I opened the motor cover and restarted. After a few seconds of running sparks started jumping through the plug boot on the coil and grounding out on a screw on the side of the coil. The more I tried to move the plug boot or wrap with electrical tape for insulation the worse it got until finally it would not start at all. My theory is that when pulling the wires while replacing the distributor cap, I damaged/broke the plug wire. The more I played with it, the worse it got. The spark took the path of the least resistance and jumped through the boot to ground, keeping the motor from running. There was no other visible arcing on the motor, I checked in the dark. What are you're thoughts? I hope it's as simple of a fix as getting new wires.

 

[12Footer]

Re: 454 mercruiser missing, lack of power

I think you found the original problem when it failed totally. Yes, the plug wires should be changed. They are very expensive for what they are, but don't buy the bargain set. Pay the extra 15 buks for the ready-made, custom set.<br /> You should then be in good shape...You changed just about everything that could cause the symptoms,after being subjected to water.<br />I do not normally advocate replacing stuff until you find the problem,and really didn't mean to this time...It get's expensive real quick. Sorry about that.<br />Let me know how it does with the plug wires.

 

[cschauerj]

Re: 454 mercruiser missing, lack of power

I ended up making another coil wire to install and that way confirm if it was the problem before I bought the plug set. I knew it wasn't the cure when I put an ohm meter on the old wire and the replacement wire and got the same reading. Sure enough, I put the replacement wire on and got the same result. I called Mercury and they suggested that the only other thing that could be wrong was the coil. I guess sometimes they can develope a crack, something so small you can't see, and that's all it takes. So..I replaced the coil, and the set of plugs that fouled out while the coil was shorting out and bingo! I made it out and back without any stalling and without calling Seatow. It ran real well. I still have the original plug wires installed but I'll probably end up replacing them down the road anyways. So I don't know what the hell was the original problem. Two different sets of symptoms. Two seemingly unrelated problems happening back to back??? At the very least I'll be very careful what I spray off on that motor. Thanks again for your thoughts. What kind of boat do you have?