Re: OT: Outboard Repair Question

From: Michael Maskalans (dml@tepidcola.com)
Date: Sun Jul 08 2007 - 11:34:57 EDT


On Jul 7, 2007, at 23:17, Jamie Calder wrote:

> I have a 2001 Sea Doo Islandia 23' deck boat, 2 stroke 240 Merc EFI
> mated to
> a jet drive.

Well even though that's probably using a similar block to the Merc
225 outboard, I don't thing a inboard jetdrive setup quite counts as
an "outboard" - though if it has left the stringers and exited the
boat that may be related to part of your problem :-)

> The RPM's won't go above 4900-5000 RPM's. Operating RPM's
> should be 5500-6000 RPM's. I did a compression check and all were
> around 130
> psi.

Good news, my first suggestion given that it's a two stroke was going
to be a burned piston, ring or valve.

If I'm not mistaken that should also ruse out intake reed issues.

> Next, I would like to verify all cylinders are firing. What's the
> easiest way to do this?

pull & compare all your plugs, if one isn't firing it'll be black &
dirty or maybe broken if that's the cause. If they all look good, do
new wires, new plugs, and if I'm not mistaken all the nower Mercs are
distributor-less so you should look at a coil pack test procedure.
If I'm wrong on that point, put in a new cap & rotor and check your
timing.

> If 1 or more aren't running, how do I tell which
> ones?

the plugs should tell that story. you should be able to check for
juice reaching the plugs with a timing light that gets signal from
clamping a spark plug wire. Just make sure it flashes on all 4 or 6
or however many thins thing has.

> Any other ideas or suggestions regarding this problem are appreciated.
> Also at idle to about 1500 RPM's the engine is extremely rough.
> More shaky
> then the 604 cam in my '93 Dakota. So if all the cylinders are
> firing, maybe
> something else is off balance like a bad impeller? Would this also
> slow the
> engine and boat down?

Could always pull the driveshoft and see how it idles. That would
tell you if you threw a blade on the pump's impeller and that was
causing some of your roughness...

Good luck.

--
   +-- Mike Maskalans ---------------- Rochester, NY ----------+
   | '98 Dakota CC, SAS on 40s  '84 RamCharger 4x4, plow truck |
   | '02 Jetta TDI 5sp, daily   '97 Intrepid, not on the road  |
   +-------------------- <http://mike.tepidcola.com/trucks/> --+



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