2005 Mercury Opti Wont Go Over 2200 RPM

[FishingKY]

2005 Opti 200, 1B176241


On the lake earlier this week and for the first 2 days it ran great. I maintain per all info on the board (cocktail in fuel, plugs every year, impeller every other year, lube, winterization, etc.). Injectors and rail previously serviced by European Marine, and reeds changed out.

On day 3 we made a 7 mile run to a marina and to fish that creek. No alarms and water pressure was around 20. When I went to head back it would not get on plane and just plowed water and would not go above 2200 rpm. Made a quick call to a great tech (who now gets all my parts purchases) and he walked me through a few things with no luck. Idled back to our on lake location with no alarms, no engine vibrations, and no apparent other issues.

Here is what was done or checked on the water or here at home...

1) checked that oil pump is working (on water)
2) pulled shift sensor plug to try to "override" a possible bad sensor (on water)
3) checked prop and sleeve
4) tried pumping bulb while trying to get on plane. bulb was always hard
5) alarm signal / horn is working
6) checked fuel for water contamination
7) checked for spark on every coil using inline spark light while running
8) pulled all plugs (pic attached) to check for damaged plugs
9) made sure I didn't take on water (in water)
10) checked cylinder compression
11) checked throttle linkage. Would rev in neutral above 2200 rpm (I know it's not good to do that but I wanted to check just once... on the water)

What would be the next steps you would do? I have the service manual I bought from European Marine to assist.

[DewRonInc]

Fuel lines are probably culprit

[EuropeanAM]

Looking at your spark plugs- can you confirm their numbering vs. orientation in the engine?

Correct view looking at the back of the engine:


2 - 1
4 - 3
6 - 5

[FishingKY]

Don,
That is correct. The labeling you show corresponds to the spark plug numbering.

Just for more info...today I verified coil drivers and coils ohms readings and all are within spec. I also verified fuel VST has no contamination. I pulled the tracker valve and it was good with no splits, nicks, or tears.

[EuropeanAM]

Recommend you get Air/Fuel pressure readings, and record results:

-At idle
-Under Acceleration (in this case, everything it will do, on the water)
-5/10/15 seconds after shutdown (restart for each time period).

Also check/inspect the belt and tensioner- make sure the tensioner can provide at least 70 lbs/in (check with an inch pound torque wrench) before it reaches the end of it's travel.

[FishingKY]

If I don't have the mercury dual gauge (air and fuel pressure) is there any reason a standard single dial fuel pressure gauge and a standard air gauge would not work?

[Rubrail]

Same thing happened to me 20 miles offshore, one engine wouldnt rev in gear. Had to replace the throttle position sensor.

[JOE54]

If I don't have the mercury dual gauge (air and fuel pressure) is there any reason a standard single dial fuel pressure gauge and a standard air gauge would not work?

needle bounce will be horrible and possibly unable to read

[FishingKY]

planning to get these results this weekend.

For the pressure gauges, I hope this works. I bought 2 fuel pressure gauges from the Chinese tool outlet. Took them right over to the local hydraulic hose shop and replaced both gauges with glycerine filled 0-160 psi gauges.

I also, finally, installed the Vessel View Mobile kit I had from last Christmas. So maybe this can provide some information.


Don,
For the "5/10/15" results, is the procedure you're asking for? Shut down wait 5 seconds, restart and record results, shut down.... wait 10 seconds, restart and record, shut down.... wait 15 seconds, restart and record, shutdown

[Bryanmc57]

I believe it's "start it then shut it down and record the pressures after 5 seconds, restart then shut it down and record pressures after 10 seconds etc"......

[SilverFox579]

I believe it's "start it then shut it down and record the pressures after 5 seconds, restart then shut it down and record pressures after 10 seconds etc"......

^^^^

[EuropeanAM]

+2... only make sure the 5/10/15 second readings are with the engine OFF.

[FishingKY]

Since I couldn't get a partner to run it on the lake I took some readings at idle. These readings are using lower unit muffs. I also captured some information from the VV Mobile, though I think some items are wrong because I don't have those elements tied in.

Can I do the 5/10/15 using the water muffs or should those be taken after running it under a load?

Tensioner pressure is good.

Gauge graduations are 4 psi
Fuel 92 psi
Air 82 psi

Max temp at idle (15 minutes) - 117 degrees



Air Pressure.jpgFuel Pressure.jpgEngine Data 1.pngEngine Data 2.pngEngine Trim Position.pngLevel Sensor Tank A.pngSea Water Temp.png

[Bryanmc57]

Can I do the 5/10/15 using the water muffs

Yes

[JOE54]

^^^^^^+1

[EuropeanAM]

Those three (3) faults are "ghost" faults (you can silence and ignore them).

[FishingKY]

Ok, so I was finally about to get out and get the fuel/air readings under full load and at the 5/10/15 seconds.

I need to just say that it actually got on plane this time. I even put water in the livewell to replicate the day the issue started. Fumes were really strong but it idled fine. According to Vessel View the temp never got above 120F but at idle speeds pretty much stayed around 117-118F. The ONLY thing different than the day I started having this issue is the spark plugs; they were so fouled (image above) that I decided to put in my gently used back up plugs (same brand and gap as those removed).

Here are the readings...

Idle... Fuel 92 psi / Air 82 psi
Under load... Fuel 96 / Air 84
5 seconds... Fuel 65 and dropping / Air 80
10 seconds... Fuel 50 and dropping / Air 80
15 seconds... Fuel 40 and dropping / Air 80

[EuropeanAM]

You have a fuel leak- and it's quite possible that the leak is leaching into the cowling somewhere. This would be especially likely if you had the cowling OFF when it went ahead and planed off this last time.

Visual inspection (pay close attention to the bottom of the STB fuel rail) when the engine is FIRST started COLD would be wise.

If you don't see it, start looking for stains, or even vapor(s).

Above all- BE VERY CAREFUL. Leaking Fuel poses a risk of FIRE or EXPLOSION. If in doubt- seek the hands-on assistance of a Certified or Master Technician.

[FishingKY]

Thanks Don. Just a few thoughts / questions...

- could the primer bulb be going bad even though it felt solid while the issue was happening?
- on the fuel Schrader valve, is the stem removable and replaceable? I notice it's slight bent, and enough I was concerned about placing the fuel pressure gauge on it.
- if I hand prime and then turn the key to let the fuel pump prime, would it hurt anything to leave it like that for 10 minutes or so while I look around?
- On the temperature, if those are factory T stats should the temp ever get higher that ~118 at idle and 120 under load? If they are factory should I replace?
- Lastly, while under load the fuel held constant at 96 lb but what are the numbers supposed to be?

[SilverFox579]

If coolant temp climbs/drops and repeats at idle your thermostats are likely fine. Coolant temp is not thermostatically controlled once the poppet opens.

I would conduct a thorough visual inspection as Don advised prior to running it again.