Diagnosing sick 2.5 260

**n.jimenez0101** · 07-05-2018, 09:29 AM

Hey guys, Happy belated independence day.

Yesterday I took my Shadow out, and the outboard has been running great for the last month or so, it's a 1996 2.5 260 that recently had the injectors flowed, compression checked, and had fresh fuel filters in plugs back in May. Yesterday it fired right up, I pulled out of the slip and idled down river for roughly 3-4 mins. I then started to advance the throttle, didn't make it more than to maybe 1/3-1/2 throttle and the engine went from its typical sound to a different sort of "wahhh wahhh" sound and lost power. I let off the throttle and it died at idle very quickly. I restarted the engine after making sure the water inlets were clean and that nothing looked obviously wrong under the cowl, and it started up but still ran rough (for what its worth the exhaust smelled different too). I then killed it, and had a buddy tow me back in since I had only made it roughly 200 yards from the marina at that point.

Other than checking the spark plugs, I don't really know where to start when it comes to trying to figure out what went wrong. Any advice on what to do (and what not to do) is appreciated. Right now the boat is on dry land so I'd like to take the opportunity to do the best I can to figure out what's wrong. There are also very few shops near me that will work on an outboard so if I can't fix it, I'll likely be taking a long road-trip which I'd like to avoid if this is something minor.

I appreciate the input guys.

-Nick

**Vecman** · 07-05-2018, 10:05 AM

Nick,

Pull all the plugs and see if they're all soaked or just a couple. Sounds like it loaded up from idling. Check throttle and timing linkage.
Make sure everything is moving freely. Post your findings and some others will jump in I'm sure. I've seen all kinds of crazy things on
these motors. Triggers, stators, loose ground wires, etc. Go over all the wiring! Make everything is making good connections.

DL

**n.jimenez0101** · 07-05-2018, 10:09 AM

Appreciate the input DL, just trying to get a good starting place then I will report back.

**rock** · 07-05-2018, 11:34 AM

I would check compression so you know you have something serviceable.

Rock

**Dave Strong** · 07-05-2018, 02:01 PM

Check fuel separator for water and fuel press.

Dave

**n.jimenez0101** · 07-07-2018, 06:20 PM

All right, spent several hours working through some
of these suggestions. Compression is normal. Fuel pressure looks good, and I put new spark plugs in. For what it’s worth, the spark plugs from one bank seemed just a little wetter than the other bank but they all looked fine. I cleaned out all the fittings on the horn, and they all seem clean. Still not running right, no idle, and very rough running in general. Any other suggestions? Thanks in advance.
-Nick

**Dave Strong** · 07-07-2018, 06:49 PM

You done a spark test? Should be able to jump 3/8" with nice blue spark.

Dave

**n.jimenez0101** · 07-09-2018, 09:56 AM

I need to do that, and still going to change the fuel filters. These spark plugs have no electrode so I'll have to figure out a decent test for them.

**Dave Strong** · 07-09-2018, 10:10 AM

Need to get spark tester, don't crank it with wires off plugs unless Leeds are grounded.

Dave

**n.jimenez0101** · 07-09-2018, 10:36 AM

Ok, I've got fresh fuel filter inbound, and a spark tester. Any other ideas? Thanks guys!

**Motv18** · 07-09-2018, 10:37 AM

Some say “ last repair is a good place to start “ probably knocked something lose and it closed up something.

**n.jimenez0101** · 07-09-2018, 11:08 AM

Originally Posted by Motv18

Some say “ last repair is a good place to start “ probably knocked something lose and it closed up something.

Haven't been having any problems with it at all, last thing that was worked on was the injectors which were cleaned and flowed (professionally, not by me).

**KIRCHNER** · 07-10-2018, 04:06 PM

check ecu harness plugs un plug and re-plug

**n.jimenez0101** · 07-11-2018, 12:47 PM

Going to go back over the ecu harness, also ordered a new fuel regulator. Going to do some work tomorrow, will report back.

**n.jimenez0101** · 07-12-2018, 08:04 PM

Well gentlemen, it appears there is no spark in the right cylinder bank, no spark in all three. I unplugged and replugged the ecu, and nothing looks obviously lose. Any ideas? Thanks boys!