Guardian Mode

[rleo57]

Optimax 2006, 90hp s/n-1B319762

Greetings, TIA for any input. My issue with the motor is low idle and an intermittent studder and engine cut out at 600rpm. At 650 it still studders but will stay on. At 850 it studders much less frequently and will not shut off. I replaced the Fuel filter (which was discolored and absent of water), replaced air filter and put 2 cans of sea foam in about 24 gallons of fuel. I do have about 8" of gray fuel line spliced downstream of bulb. Line is rock hard. I know not to replace with auto parts line. The od is 1/2 " but I'm not sure of the barb. Pulled plugs that are 2-3 yrs old and did have dry carbon on them and 1 plug had a piece of loose carbon between the firing pin and top horizontal bar. Sorry about that discription. Cleaned them and put them back in. All this was done before the rpm data. Regarding Guardian my question is does it go into protection mode limiting rpm to 2200? When I was checking rpm I was docked and was increasing throttle and have since read here that that is not recommended (neutral overspeed). Can it go into guardian mode without any beeps, because it never did beep. I wasn't sure how to reset the mode or that it could possibly be causing the underev so I left the lake. I do have the ear muffs and a single fluid filled gauge (0-160)to check pressures which I have not done. Hope this provides adequate information.

Thank you,
Richard

[EuropeanAM]

Richard:

Those plugs are way overdue for replacement. START THERE. Use ONLY NGK: IZFR5J spark plugs.

I would discontinue the cans added to the fuel. Mercury's Quickare and Quickleen (1 oz each per 5 gallons fuel) works quite well for everyday use in your Optimax.

Guardian: When a fault or condition that warrants Guardian is present, the PCM can limit the available power anywhere between 99% available power and FORCED IDLE (5% or less available power), depending on the severity of the situation. Most such occurrences are accompanied by a Warning Horn signal.

Fuel line: See the following link: FUEL LINES AND PERFORMANCE PROBLEMS

[rleo57]

Replaced plugs and did seem to start with more gusto unfortunately it still cuts off. I do have a single liquid fill gauge and had it on the fuel rail test port. It studdered and cut out and the pressure dropped to 42psi immediately. 2nd time it dropped to 101 and 3rd time to 40. I know I should have checked the air pressue and low pressure fuel but didn't. I ordered another gauge and will have more info but does the facts provided so far enough for a diagnosis?

[Extremeboating]

It somewhat sounds like you may have fuel line issues. You may want to investigate either polyurethane, or tygon line replacement for the gray junk that modern day fuel lines have. Also, are you losing pressure on the fuel bulb?

You may have a blockage caused by the internal liner in the line. Hopefully you don't, but if you do that can cause issues upstream into the hard fuel pumps and cause further issues even after you replace the line.

[rleo57]

Bulb has very little pressure loss. Thanks

[JOE54]

Replaced plugs and did seem to start with more gusto unfortunately it still cuts off. I do have a single liquid fill gauge and had it on the fuel rail test port. It studdered and cut out and the pressure dropped to 42psi immediately. 2nd time it dropped to 101 and 3rd time to 40. I know I should have checked the air pressue and low pressure fuel but didn't. I ordered another gauge and will have more info but does the facts provided so far enough for a diagnosis?

does sound fuel pressure related dropping that much

[EuropeanAM]

I would not start removing ANY components until you have reliable pressures from a GLYCERIN dampened DUAL pressure gauge set.

Reason: If air pressure dumps, the fuel pressure dumps right along with it (instantly). Especially common when a rivet is loose on the air compressor reed plate.

[rleo57]

Thanks will do. Picking it up from storage tomorrow and got the second gauge today.

[rleo57]

Greetings, I put the gauges on and found the following. Low fuel pressure key to on- 26psi then drops to 15 and stays there. When engine is running pressures are the same 26 without deviation then drops to 15 when motor is off. High pressure fuel (on) 108, air pres 94. Both stay the same until it cuts off a few seconds to a minute. Upon cutting out completely with no deviation of pressures the fuel pres 100 and air 88. At 5- sec 98/88, 10- 98/97, 15-98/87. Not getting that huge fuel pressure drop to 40 as before. Is it starting to look like its not fuel related? TIA

[EuropeanAM]

Except for the mysterious increase in air pressure between 5 seconds and 15 seconds.

[csurp]

My 2007 115 Optimax used to drop a cylinder when a coil failed. Were your coils replaced under the now expired extended warranty? I imagine the spark plug with the bad coil will be pretty wet.

[rleo57]

LOL Typo. I'm a 1 finger typist so I have no excuse or do I. Should have been 87.

[rleo57]

csurp....No they weren't. I will pull the plugs and check thanks.

[rleo57]

Checked the coils and when removing coil wiring at harness #3 (lower) cylinder it wouldn't have any effect on engine rpm. Switched coils 2 & 3 and #2 had no effect and 3 worked fine. Ordered coil and will reply with results once tested. Thanks for everyones help.

[JOE54]

[EuropeanAM]

You're on the right track now.

[rleo57]

Sorry for the late update. The coil was the problem and has been running fine. Great group of people on this board!!

[EuropeanAM]