88 Mercruiser dead in the water

[clint hawkins]

Initial problem: boat will turn over but not crank up. I first checked the kill switch and fuse. They were good. Next I pulled off the breather to see if I was getting fuel. Sprayed starter fluid and tried to crank again and it wouldn't. Next I checked the distributor cap and replaced it. That didn't work. Then wires, then spark plugs. No help. I then went to check to see if there was spark getting to the plugs. I took one plug out, grounded it to the engine, turned the key, and the engine ran. I shut it down,replaced the plug in the hole, and it wouldn't start. I took the spark plug back out and it cranked as soon as I turned the key, no problem. I then put the plug in, took the wire off the plug, and it wouldn't crank. I replaced the wire, took a spark plug out of the opposite side, and it fired right up. I removed the valve covers to ensure that all my valves were properly seated and functioning, everything looked great. Best I can figure, I have a compression problem with the exhaust, but I don't know enough about it to say for sure. The compression on each of the spark plugs is good. but the engine will not run unless I have one spark plug out of the hole. Did the 88 model come with gremlins? Appreciate any feedback. Thanks a lot. Clint

 

[flashback]

Re: 88 Mercruiser dead in the water

Thats some pretty crazy stuff! I'm no expert but the only thing constant in your senario is the grounding of the plugs. I think its electrical but darned if i know what.. Bruce

 

[SS MAYFLOAT]

Re: 88 Mercruiser dead in the water

I would leave all the spark plugs in the engine, then take the coil wire from the distrbuter and leave about a quarter inch gap from ground and then turn the motor over. If you have spark that can jump that gap, it should be good enough. If the spark doesn't jump, it could be a weak coil. But I think maybe you should check your firing order. It is possible that is why it is running when you have the spark plug out.

 

[SS MAYFLOAT]

Re: 88 Mercruiser dead in the water

Sorry but I forgot to mention that if it is electronic ignition and you don't have a coil wire, then try using the plug wire with a screwdrive stuck into the socket and leave about a quarter inch gap.