4 stroke merc 5 hp, about 5 years old

Ok m friend lends me his 5hp merc 4 stroke to try out on my 12' tin boat.

He says it won't start now, but used it over the july 4th weekend.

I've repaired my 2 stroke OMC motors in the past, and feel confident about fooling with this beast.

here's what I don't get- the oil light flashes when i try to start it, he says it shouldn't. I see the emergency kill switch is in series with the oil press switch and ground. when i ground a removed spark plug there is no spark (like I always find when checking for spark on a 2cyl)

So I'm wondering if the no spark could be from a dead module, or something about the oil pressure sensing switch is keeping the CD module from firing a spark out to the plug.

Are these 4 strokes more cantankerous than a comperable 2 stroke?
thanks in advance

Re: 4 stroke merc 5 hp, about 5 years old

Download a service manual for it HERE. You should find all you need in there... (Password for the file is <ribforum>.)

Re: 4 stroke merc 5 hp, about 5 years old

Thank you SOOO much.

I downloaded it and browsed thru it all. now I can test the components.

So am I correct in thinking that there is nothing to prevent the plug from showing a spark when held to the metal motor head and cranked? If all is Ok ,

I know it sounds like a dumb question, the system shouldn't know if the plug is screwed in, or not, to my pea brain!
thans again!

Re: 4 stroke merc 5 hp, about 5 years old

rewinder said:

...So am I correct in thinking that there is nothing to prevent the plug from showing a spark when held to the metal motor head and cranked? If all is Ok ,

I know it sounds like a dumb question, the system shouldn't know if the plug is screwed in, or not, to my pea brain!
thans again!

Click to expand...

You are correct, as long as the plug is resting against a piece of bare metal, spark will ensue....