2007 optimax 150 reeds?

[Iowabass3826]

Don,

SN: 1B426909
150L OPTI

last trip out the motor would hop up on plane like normal, but when cruising around 3500-4000 rpm it would intermittently cough or misfire. I also was down a few hundred rpms on the top end. I've been doing a bit of digging and have found a red wire on coil three was rubbing on the spark plug wire to the point of copper showing on the red wire. I'm hoping this is the source of my trouble. Spark Plugs have been replaced and the wires as well.

however, when reading through a few posts I'm noticing similar symptoms when there is a reed failure. Would this year/model be commonly affected by a broken reed or a failing ignition coil?

[Wildcat Dude]

My question would have to be, have you ran with new plugs & wires yet? I don't see the need to fix something that isn't broke (YET)

NGK IZFR5G @ .032-.033"

[ChrisCarsonMarine]

Yes,this motor is known to suffer from broken reeds often,and if you wait to break one off completely it may cost you a piston...Chris

[EuropeanAM]

Don,

SN: 1B426909
150L OPTI

last trip out the motor would hop up on plane like normal, but when cruising around 3500-4000 rpm it would intermittently cough or misfire. I also was down a few hundred rpms on the top end. I've been doing a bit of digging and have found a red wire on coil three was rubbing on the spark plug wire to the point of copper showing on the red wire. I'm hoping this is the source of my trouble. Spark Plugs have been replaced and the wires as well.

however, when reading through a few posts I'm noticing similar symptoms when there is a reed failure. Would this year/model be commonly affected by a broken reed or a failing ignition coil?

Make sure you used the correct (IZFR5G) plug, at the correct GAP (they do NOT come gapped correctly in the box). Verify they were torqued to specification (20 lbs/ft) with an ACCURATE torque-wrench.

Definitely address the damaged wire. That very likely is the source of your problem (if not, it WILL be a problem).

Coil failure on this model isn't very common (quite rare, actually).

Reeds: Definitely wise to consider upgrading those... replacing the steel reeds with Fiber reeds (I recommend and sell TDR reeds). More information can be found here: INTEGRITY Injection

Be sure to report back....

[skatermike24]

I installed a set of Chris's reeds in my opti, never idled so good , good guy to deal with, give him a call.

[Iowabass3826]

As a follow up to my first thread- The motor continued to miss after replacing the spark plugs, fuel filter, and repairing the #3 coil wire. I took the boat to my local Merc. dealer to have him look it over. Much to my disgust, the dealer had the boat for close to two weeks and simply performed an fuel/air pressure check, and allowed the boat to idle in his test tank to try and duplicate the misfire. The pressure checks were reported as good with a 10 psi variance between fuel and air. The motor also never acted up at idle (as I expected). I test ran the motor and it seems to only be acting up under load (1000-3000 RPMS). I am in the process of checking both the reeds and the exhaust tuner, as several other posts have indicated similar problems and found these items to be the culprit. My question to Don- The TPS control arm coming out of the TPS sensor itself seems to have a TON of play in it. The boat has in the past done a weird high idle first thing in the morning as well. Could these symptoms be related and also now causing a misfire?

[EuropeanAM]

Not impossible... and if there is OBVIOUS wear there, it's wise to replace the TPS, cover, and arm (all at the SAME time).

[Iowabass3826]

Don- PM sent.

[Iowabass3826]

Found the source of my problem I do believe- broken exhaust tuner laying in the bottom of the mid section.

Can the power head be lifted straight up with the flywheel lifting eye far enough to make this repair without disconnecting too many things? As of now I only have the lower unit and lower cowling apart. Looks like there is about 10 nuts that connect the driveshaft housing to the power head?

Three exhaust tuner studs remain while one may be gone or snapped off.

[aussiejake]

strange this tuner problem was just a Mercury bulletin ......should have been a recall.

Mercury even SELLS a kit to fix their problem!

All 2.5 mercury motors from 2003 thru to 2008 are subjected to this fault.

Nylex nuts on an exhaust component is a joke!

You will need the gaskets, bolt kit and possibly a new tuner as yours will be warped or cracked.

The mercury shops in Australia charge $500 plus parts to fix the MERCURY problem.

[Iowabass3826]

Aussie-

do you have the part number for the kit?

SN: 1B426909

[EuropeanAM]

EVEN if you buy the "kit"- DO NOT USE NYLOCK NUTS TO RETAIN THE TUNER.

Obtain STAINLESS bolts (and washers) of required lengths to secure the tuner (with RED liquid loctite on bolts).

Never been a fan of nylock nuts in an area that runs extremely high temps (far above what is needed to melt nylon).

In addition to the above, be sure to obtain (and install) this gasket between the tuner and the adapter plate: Part# 782461 (your engine may not have had this... or even call for it). This gasket does help with reducing vibration.

Yes, the powerhead can be lifted straight up, with much of the rigging still intact (if you are VERY careful). The exhaust (adapter) plate must still be removed from the midsection, as the tuner secures to the underside of that plate.

[RiverRat318]

Thanks. One question I still have: does my engine fall under the bulletin that reccomended that all coils be changed at once?

[SilverFox579]

Thanks. One question I still have: does my engine fall under the bulletin that reccomended that all coils be changed at once?

Reply back to your post in the 2.5L forum.