2006 sugar sand tango xtreme 240efi

[Firecat700rr]

Was hoping maybe someone could point me in the right direction? Bought this boat and it seems to start and run just fine at slow speeds. Outta the hole it pulls about 5600 rpm then tapers down to about 5000-5200rpm and only does about 45mph was expecting more top speed? It feels like something is holding it back on top end. When you turn lightly to the left rpms drop turn to the right alil they raise alil. Anybody have any ideas where to start be greatly appreciated. Thanks

 

[Blkrvrbart]

Check the intake and impeller first. If you sucked in a chunk of debris, rope, moss, etc. it could be the problem. If not then look for fuel delivery and spark. Clogged filter, fouled pugs, etc. Then if you still have trouble look at the ignition system.

 

[Bilmon]

Agree with @Blkrvrbart suggestions, start with the simple. Check your fuel lines and filters, check compression, on the 240 check the fuel pressure of the high pressure pump, should be something like 40-45 at the "tire valve" on the top front of engine, checked with key on engine off. Also plugs, 2-strokes are fussy about them, and make sure all coils are good, check all connections. You can be down a cylinder and still run and sound pretty good. That boat should knock on 60mph, my kid's 07 240 SS can do 62 GPS under the right conditions, my Mirage 240 has hit a best of 55.7 and it weighs several hundred lbs more. Here's a link to the service manual for your engine; Boatinfo - Mercury Service Manual for 240 EFI JetDrive

 

[Firecat700rr]

I’ve changed the fuel filters maybe it’s dropping a cylinder in the upper rpm’s I’ll investigate. Easiest way to check comp pull teather crank over at wot? Thanks

 

[Firecat700rr]

Well bought all new plugs and checked fuel pressure according to my gauge it was 50psi? Checked wires and coils and have concluded that cylinder driver side all the way to the bottom is not firing? Coil maybe? It’s wet one on bottom across from it is damp too but not soaking wet like driver side. Also running I can pull that plug wire and here no change in motor sound or no arcing off plug wire like I can here on the rest of them. Thoughts? Check compression too is was about 130 on all cylinders.

 

[Bilmon]

Compression is good. Swap a couple coils around, they are all the same, and see if it changes the dead plug position, that will quickly tell you if the coil is bad. I've had a couple of them fail, I keep a spare on hand now.

 

[Firecat700rr]

Yup you were spot on lol i switched them around them cylinders picked right up. The other one on the bottom across from it seems dead too is it possible this boat can still do 45mph on 4 cylinders? Find it hard to believe 2 are dead but seems to be the case? Thanks again

 

[Bilmon]

I know my Mirage runs quite well on 5 so the lighter Tango on 4 is believable, I am a little surprised it starts easily. Truth be known I think the 1400 lb. Tangos are almost over powered with the 240 . If you are new to them your gonna be shocked at how hard they jump out of the hole and accelerate when its running on all 6.

 

[Firecat700rr]

I’ll keep you posted but as far as I can tell it’s down 2 cylinders. Prolly explains why the motor doesn’t have that aggressive sound they say they should have. Besides a inline tester on the wire is there anyway to test the coil (cdma) I think it’s called? Thanks

 

[Firecat700rr]

I stand corrected it was only #5 coil that was down with one cylinder coil bad like that would it only allow the boat to do like 45-48 though? Using one of those inline spark testers to test spark.

 

[Bilmon]

I stand corrected it was only #5 coil that was down with one cylinder coil bad like that would it only allow the boat to do like 45-48 though? Using one of those inline spark testers to test spark.

I would think that would do it, spark tester is what I use. There is a ohm chart in the service manual that might help find a weak one but if it fires when you swap them around and that coil stays dead it's most likely bad. from the manual

 

[Firecat700rr]

Thoughts on being down a cylinder loose that kind of top end ? Just looking for ideas if maybe I need to look somewhere else too? I’m going to try coil first hoping for a good pickup in speed though I guess lol. Any coils for these mercs are the same as long as there similar to my plug in right I think? I ordered one out of a seadoo but it looks like mine. Thanks

 

[Bilmon]

Thoughts on being down a cylinder loose that kind of top end ? Just looking for ideas if maybe I need to look somewhere else too? I’m going to try coil first hoping for a good pickup in speed though I guess lol. Any coils for these mercs are the same as long as there similar to my plug in right I think? I ordered one out of a seadoo but it looks like mine. Thanks

SeaDoo used Merc Sportjets for several years. I'm pretty sure you found your problem

 

[Firecat700rr]

Hoping so I’ll keep you posted just hope all the efi 240 coils were the same I’m thinking I read that they were? Thanks again

 

[Bilmon]

Merc part # is 879984T00 looks like 29 bucks on Amazon

 

[Firecat700rr]

That for 06?

 

[Bilmon]

That for 06?

There are only 2 versions of the 240, 1st gen up to 01 or 02 and 2nd gen on up. Just did a quick parts search and that came up, it's for the 2nd gen which you and I have. Looks like Mercury uses it on the Otimax and other engines as well

 

[Firecat700rr]

Mercury Jet Boat Seadoo 210 240 hp EFI M2 CDM Ignition Coil 827509T7 Oem

That was coil I ordered not same part #? Hope I didn’t screw up?

 

[Bilmon]

Mercury Jet Boat Seadoo 210 240 hp EFI M2 CDM Ignition Coil 827509T7 Oem

That was coil I ordered not same part #? Hope I didn’t screw up?

Just looked, that's the part for the 1st gen 240, don't know if they are compatible or not

 

[Firecat700rr]

Mine has a heat sink looking thing on bottom these don’t? Mighta screwed myself lol