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noah
 
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Default 1983 15 hp Johnson o/b that just won't run right!

On Tue, 12 Aug 2003 02:27:34 GMT, "Bill Lavernoich"
wrote:

The problem with the 15 hp is as follows.

I bought this motor two years ago from a guy who claimed to be selling it
for the wife of a deceased friend. He didn't have much info on the engine
except to say it had not been run in at least 5 years. (I willing to bet it
was like 10 or more years.)

Although originally I could not get it started, I've now had it serviced by
three different repair shops, all with OMC backgrounds. It's been
decarbonized, had the carburetor cleaned and rebuilt, new plugs and had
numerous other minor issues resolved. The water pump hasn't been overhauled,
but the mechanics have all claimed that the impeller is fine as the engine
produces a sufficient "pee-stream." However, the big problem hasn't been
solved.

When the engine hasn't been used overnight or for a few days, it starts on
the first or second pull and will idle OK. It will also run fine under full
power on that first run and push our 14ft aluminum skiff at 20-25 miles an
hour. From that point the reliability goes downstream fast and has me ready
to use it as an anchor.

The fun starts when the engine will not idle after being run at full or half
throttle. It will also not restart easily if it is hot and/or has stalled
out. You can sometimes get it started if you override the neutral-start
interlock and immediately give more throttle than the "over-rev" limiter in
neutral will allow. I know it's dangerous and for that reason won't let my
kids drive it. Letting it sit for a while, an hour or so, gives you a better
shot of restarting it, but not reliably and/or keeping it running.

Ironically, when I've picked it up, all the shops have told me how great it
runs in the test tank; they claim it starts right up, idles nicely and runs
as well as can be expected for this age motor. I don't doubt that it does
(in their test tanks), but I think they're all missing something. On the
other hand, I'm sure they think I'm neurotic about this engine.

Any thoughts suggestions or insights would be greatly appreciated.

Bill Lav


Bill- I suspect that the engine shops haven't run this engine long
enough to heat it up. Time is money, ya' know? )

Your problems sound like they are heat related, which could be a coil
breaking down, condenser breaking down, etc. Call the last guy that
worked on it and ask if he guarantees his work. If not, move on, and
find a shop that will do it right.

FWIW, get the impellor replaced. If the old one is brittle and
cracked, it could "pee" at idle, and fail to move enough water at WOT.
It's also possible that there's a partial blockage in the water flow.

Finding a good boat mechanic is a lot like finding a good car
mechanic. You pays your dollar, and you takes your chances. I've
been 50% lucky, I've got a great boat mechanic.

Good luck,
noah

Courtesy of Lee Yeaton,
See the boats of rec.boats
www.TheBayGuide.com/rec.boats