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2007 optimax 150 hp xl problem

C

camuchi

New member
I have a 150Xl optimax 2stroke that will only run at @ 4200-4400 rpm max full throttle. Also seems to be be weak throughout powerband. It was also having a running problem - it would run along at 4300 rpm full throttle trimmed out and it would kind of stumble, rpms would drop to 3500-3600 and it would then pick back up and run. That has stopped - I think it may have been water in the fuel, I have a Racor unit on the fuel line and did have some water in it. Engine starts and idles fine. Boat is a 19 foot mako bay boat.

Any ideas? Should I pull the plugs and have a look? Can i check the injectors? I Really can't fund a trip to the dealer right now.
thanks, Matt
 
Re: 2007 optimax 150 xl problem

Not much you can troubleshoot on an Opti in your driveway - most components can only be tested if you plug her into a DDT at a dealer.

A new set of plugs would definately not hurt - Opti`s are very hard on them (50 to 100 hours of use and they are toast).

Also, run new, stablized gas - add in some Seafoam to clean out carbon and other cooties that may have collected in the system.

There is also a filter in the Vapour Separating Tank (VST) that could be affected by water. But you may be experiencing a fuel pressure problem from either a problem with one of your two fuel pumps or even a bad tracker valve in the rails.

It could also be one of the many sensors that this motor relies upon to run.

I would try the new gas and sparkplugs, but if that makes no difference you really are going to have to make that trip to the shop.

Opti`s are not a motor that you work on in your driveway with a screwdriver in one hand and a multi-meter in the other...
 
Re: 2007 optimax 150 xl problem

Thanks Galamb,

I will try some plugs and try the seafoam treatment- probably mix up five gallons or so and go run it through rather than buy enough seafoam for my big tank. I always use stabilizer and ethanol free fuel. What is in it is Chevron 93 wiuth stabilizer but it is back from November, I may have some of that winter/summer gas mix problem, plus the age.

What the heck is a tracker valve?? I have seen some shrader valves on the fuel rails- same thing?

Two fuel pumps? are they both on the engine?

Is there ahnywhere I can get a blow up view of this motor?

Reccomendations on where to go for parts online?

What ?? no Multi meter diagnosis - that could be construed as a challenge -ha ha.

Thanks for the help
 
Re: 2007 optimax 150 xl problem

The Opti's really are a "space age" design - far more techically advanced that any 4 stroke on the market.

The orbit direct injection system, used by Merc and Tohatsu uses (ultimately) two injectors per cylinder.

The first injector is fairly conventional, just like you would have on your vehicle. It injects the gas into the fuel rail.

The second injector, the "direct" injector, injects the fuel into the cylinder head once the piston has already traveled far enough to close off both the intake and exhaust ports - so no gas escapes out the exhaust like on a (conventional) 2 stroke.

The intake port on the cylinder sends an air/oil mix into the cylinder which is there "waiting for the gas" from the direct injector - so the only place your oil and gas mix is directly in the cylinder head.

The fuel in the fuel rail is pressurized to about 90 psi. These also have an "air rail" (which is integral to the fuel rail) which is pressurized by a single cylinder (piston driven) air compressor. The air is used to make sure the gas charge is pushed through the direct injector. The air rail is pressurized to about 80 psi (consistantly 10 psi less than the fuel rail and they do fluctuate in pressure) the pressure balance is tracked by the ECU by means of a MAP calibrations (manifold absolute pressure).

The tracker valve's job is to make sure that the pressure balance is always 10 psi apart as the pressure fluctuates. Each port on the fuel rail corresponds to a particular cylinder, the air rail is (common) - shared amongst all cylinders.

Yes, two fuel pumps. There is a conventional crankcase driven (diaphram) pump just like on every outboard out there which sucks the fuel from the gas tank and sends it through a water separating filter. The crankcase fuel pump maxes out at about 10 psi of fuel pressure - insufficient for direct injection.

From there the fuel goes to the vapour separater which contains the electric pump. The electric pump raises the fuel pressure to somewhat above 90 psi - required for the fuel rail. Excess fuel at the rail is first water cooled (to remove heat caused by "compressing" the fuel in the rail) and then returned to the vapour separator for "re-use" in the rail.

There are some very minimal electronic tests that can be done on these with an ohm meter, but really, for troubleshooting you really have to hook them to a DDT.

The ECU's are preprogrammed with "normal" outputs from each of the sensors. So if you disconnect one "to see if it's the problem", the ECU will pretend it's there and feed itself "what it expects to see from that sensor".

Of course, if you run with a sensor disconnected, performance and fuel economy will suck, because the "fake" readings do not change or vary.

There are complete parts diagrams available at www.mercruiserparts.com or www.crowleymarine.com - just to name a couple...
 
Re: 2007 optimax 150 xl problem

Wow, what great information. I am a 'gearhead' and love to know how all of my stuff works. How did you come to know all of this stuff? Are you a mercury technician?

I have worked on plenty of late model FI automotive engines but I certainly agree w/you this is not one to try and figure out on my own w/out the proper diagnostic tools. And I bet the testing unit is mighty pricey. So I will try the sparkplugs, filters and fuel and if that doesn't help I will have to go see the Merc dealer.

thanks
 
Re: 2007 optimax 150 xl problem

Although I have been working on outboards, primarily Merc's for a good 30 or so years now I am not "certified" by any mfg - just a "run it out my garage wrench bender".

I do however, keep as up to date as I can on anything 2 stroke in the Merc line-up.

When the Opti's came along I figured if I ever planned to work on them I better understand how their systems work, since they really are VERY different from others out there. So I picked up a set of service manuals for the entire Opti line and started reading :)

And yes, the software to do the diagnostics is probably not worth it for the average guy working on his/her own motor.

There is some multi-mfg software out there that you can install on your laptop (covers Verado, Opti, 4 stroke, 2 stroke, Yamaha and maybe a couple others), but too expensive even for a guy like me who sees maybe three dozen engines a season and normally less than half a dozen are ECU/ECM controlled models.

The Merc dealer (that I can see from my back yard looking accross the farm field) only charges 60 bucks to "plug her in and give a readout" - even if I charged the same it would take maybe 5 years before I recovered the cost of the software and by then it would be well out of date/require upgrading.

So unless you are "factory authorized" or do a whole lot of servicing, or are buying just the specific software package for your exact model, for the few times you may need a readout, the DDT at a dealer is the cheaper way to go...
 
Re: 2007 optimax 150 xl problem

If you are concerned that the problem you are having is fuel related, take it to a dealer fast. Any Mercury/Mariner dealer that means business will have the facilities to test the fuel injector and the direct injector.

One of my customers found out the hard way;

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Re: 2007 optimax 150 xl problem

Wow that will scare ya!
What happened? Did it run lean? I know
You guys are way ahead of me on these motors
And I am confused here. If the oil/ fuel
Is only mixed in the cylinder how are the rod
And main bearings lubricated? I have seen
Old two strokes drop a rod like this when
The oil inj system goes away or the owner
Screws up the mix. Does the optimax have
A crankcase/sump oiling system???
 
Re: 2007 optimax 150 xl problem

One of the direct injectors packed in.

Here is the Optimax oil injection system explained for you;

Oil is stored in a reservoir on the engine. The oil pump is actuated by the PCM and distributes oil to the crankcase and air compressor. The oil pump has seven discharge ports with an oil delivery hose attached to each discharge port. Six of the hoses are connected to the cylinder intakes near the reed assembly. The seventh oil delivery hose is connected to the air compressor for lubrication. The unused oil from the air compressor returns to the cylinder bores. If an optional remote oil tank is used, the crankcase pressure forces the oil from the remote oil tank into the oil reservoir on the engine. The PCM is programmed to increase the oil supply to the engine during the initial engine break‑in period. The oil ratio is doubled during the first 120 minutes of operation whenever the engine is under a load. At idle the oil pump is providing oil at the normal ratio. After the engine break‑in period has expired, the oil ratio returns to normal.
 
Re: 2007 optimax 150 xl problem

About your sparkplugs - I don't have any info on the iridiums, but everything that has ever gone in these was gapped at .040" - so probably a safe bet..
 
Re: 2007 optimax 150 xl problem

Hey thanks so much to both of you guys.
I love to learn about this stuff. I had no idea
How much technology was in this 2 stroke
Motor. I bought the boat with a whole in it
From an auto accident and didn't even know
The engine only had 130 hrs on it. Well
I am even more pleased now.

I installed the new plugs today ngk iridium
Gap was .032 marked on the data plate.
Old plugs looked evenly worn showed a
Pretty rich (black sooty) overall condition
Found one plug with the wire not snapped
On the tip fully and some evidence of
Arcing. So cleaned up the connection and
Used a little dielectric grease on each one( sparingly)
I suspect that and the old plugs may have been
Culprit of low rpm. I will give it a quick run
With fresh gas and seafoam and see. If it
Doesn't straighten up I suppose a trip
In for a computer diagnostic is in order.

Thanks again. I will report back.
Matt
 
Re: 2007 optimax 150 xl problem

The Opti's can be quite hard on plugs with 50 to 100 hours before they are toasted not an uncommon situation.

It's a byproduct of the DI design that Merc uses. OMC first played around with the same engineering before the Ficht line and one of the big reasons they didn't use the Orbital design that Merc has adopted was because it "ate sparkplugs" (and they couldn't get it tuned the way they wanted).

I don't know if the iridiums will last better - keep a close eye, check maybe every 50 hours and if they don't fair well perhaps switch back to the lower cost "regular" plugs at the next change - the regular ones are expensive enough....
 
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Re: 2007 optimax 150 xl problem

The Iridiums are what is specified for this motor - NGK 5887. I thought about trying a lower cost plug but after learning about this engine a little decided against it. The were not too bad @ $10.99 ea at Advance auto parts, same plug at West marine is @ 15$.


What are your thoughts on 2 cycle oil ? Mercury Marine only for this engine I bet!
 
Re: 2007 optimax 150 xl problem

For the Opti's you absolutely have to use a DFI rated oil. At least in Canada I have not seen anything with that rating beyond the Merc and BRP branded stuff (assume Yami has something as well, but there dealers are few and far between up my way).

Even in the aftermarket/major oil company brands I would be leary of any oil which states (multi-purpose) or that it's "also safe" for DFI's. Why take the chance with a 15,000 dollar engine for the sake of a few bucks. I'll let someone else try it first...

Because the oil and gas don't mix on these back at the fuel pump like on a conventional 2 stroke, you have to rely on air alone getting the oil through the reeds, intake and lower crankcase then into the cylinder where it finally meets the gas.

Heavier oils just won't atomize properly to be carried by the air alone. So if you trade your motor in every couple years or have a sponsor with deep pockets you could run "dinosaur oil" - but for most of us, using something less than the properly rated oil can cause a quick trip to the engine rebuilder.

But in the bigger picture, although the DFI oil is often double the cost of normal TCW-3, since the Opti has (the equivalent of) mix rates approaching 300:1, you use substantially less than than half and closer to 1/3 the oil that even a EFI 2 stroke would. So the oil costs more but you use way less = still save money on the cost of oil.

Thanks, I will make note of the plugs. My sheets are a little dated (I see).

I had (according to Merc) - Champion QC12GMC's gapped at .040" for 2000 and older models - NGK PZFR5F-11's gapped at .040" for 2001 and newer. Looks like they snuck in a change when I wasn't looking :)

(originally forgot to add) - The Evinrude ETEC's are capable of running either normal TCW-3 OR DFI oil (their system is a little different) but you can't flip-flop back and forth. At delivery time you either "flash the engine" to run on one or the other. If you use the regular oil it will feed at alot lower ratio than if you use the DFI oil - so again, no real savings but a convenience factor for the owner if they are running in an area where getting the higher grade oil might be difficult. I kinda expect Merc might at least look into this at some point.
 
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