125hp 2003 Mercury having issue

[antzboat]

I have a 125hp 2003 elpto 2+2 Mercury outboard (it runs on two cylinders under 2500rpm and all 4 above) Last year my motor went under water. I pickeled the engine and got it running and it sounded like it was running fine. The next day I went to start it again and it was not running right, the RPMs would spike up and down and eventually it would stall out in neutral. I got 4 new spark plugs and after I looked at them i noticed the top two turned black on the tip and the bottom two still looked brand new like the bottom two cylinders were not working.

I thought I had it fixed and went for a test drive in the water, and it actually felt like it was getting up to normal cruising speed for a few minutes, but then after a few minutes I couldn't get it to go faster than a few mphs, I would press the throttle forward and it would not accelerate

I plan to try and repair it in a couple weeks and am looking for some advice on where to begin, maybe someone had similar problems, or can give me some tip? Thank you.

 

[antzboat]

No Title

 

[flyingscott]

What do you mean by pickled. The 2 cyl should be kicking in at 1800 rpm not 2500

 

[antzboat]

What do you mean by pickled. The 2 cyl should be kicking in at 1800 rpm not 2500

When an outboard gets submerged you pickle it by soaking it in wd40 or diesel. And yes it may kick on at 1800rpm not 2500rpm, somewhere around there.

 

[flyingscott]

Start with a compression test and usually as long as the motor was not running when it went down should be salvageable. Check for spark and check all your electrical connections also did you completely drain the fuel and oil systems. Usually when an outboard goes down you try and start it as soon as possible and get it warm to get the water out. The bottom 2 cyl should are controlled by the carbs so make sure they have spark.

 

[antzboat]

Start with a compression test and usually as long as the motor was not running when it went down should be salvageable. Check for spark and check all your electrical connections also did you completely drain the fuel and oil systems. Usually when an outboard goes down you try and start it as soon as possible and get it warm to get the water out. The bottom 2 cyl should are controlled by the carbs so make sure they have spark.

Hi Scott, yes compression is perfect in all 4 cylinders 130 on all. No it was not running when it went under. Yes the fuel was completely drained and I have it running off an external tank as well. It seems to be getting spark. I got it all cleaned off and it sounded like it was running great but the next day is when the problems started with it spiking in RPMs and stalling out and the bottom Two spark plugs still look new like they aren't doing anything, Maybe it's something electrical.

 

[flyingscott]

You need to use a spark tester an adjustable one, the bottom 2 cylinders always fire. Then check all the electrical connections most marine fittings are water resistant not water proof. Saving the inside of the motor is only 1/2 the battle all the all the electrical was under water to. So check them clean if necessary and use die-electric grease when you put them back together. I would also pull the flywheel and see whats going on under there. Were the carbs drained and cleaned.

 

[antzboat]

You need to use a spark tester an adjustable one, the bottom 2 cylinders always fire. Then check all the electrical connections most marine fittings are water resistant not water proof. Saving the inside of the motor is only 1/2 the battle all the all the electrical was under water to. So check them clean if necessary and use die-electric grease when you put them back together. I would also pull the flywheel and see whats going on under there. Were the carbs drained and cleaned.

I pulled the flywheel apart and it looked okay inside everything was sealed. Also drained and looked at the carbs and they looked ok but did not give a thorough cleaning. Should I try something like seafoam or carb cleaner that I can add to the gas? Pulling the carbs apart is a huge pain, the engineering behind it is a nightmare and a huge pain to put back together so I would prefer not to do that again if I can.

 

[flyingscott]

You can try seafoam i have had mixed results with it. The carbs on those are fun you may have to take them apart buy the kits that have the accelerator pumps.