-----Original Message-----
From: owner-dakota-truck@bent.twistedbits.net
[mailto:owner-dakota-truck@bent.twistedbits.net] On Behalf Of Michael
Maskalans
Sent: Sunday, July 08, 2007 11:35 AM
To: dakota-truck@dakota-truck.net
Subject: Re: DML: OT: Outboard Repair Question
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/> --+I know it's not a true outboard but if I said inboard it would sound like it was a marinized car engine. It's known as a Mercury 250 when used on true outboards. It's down rated to 240 when used on a jet drive due to the power loss through a jet drive. Hopefully it will stay attached to the stringers and not become a true outboard (although the roughness may shake it lose)!
I'll hook up a timing light but I still may get a false reading. As with my friends Johnson (and my '96 Dak) we were getting spark but not enough to fire. A new coil pack fixed his problem and new coil fixed mine.
Thanks for your suggestions!
James
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