2-Stroke 83' Mercury Inline 6

[dwyork@hotmail.com]

I got this boat and motor last summer and it ran great for about 2 minutes and then it started stalling out. It wouldn't die on me but I was limited to about 10 MPH at WOT. Anyway, I checked the compression today and I was right between 100 & 105 on 1 thru 4 & 6, but #5 was at 90. The boat set for about a year and a half and I changed all of the fluids, but there was about a gallon of gas in the tank and not knowing anything about outboards at the time I put in about 10 gallons of 89 octane gas that contains 10% ethanol on top of the old gas. At this point I feel like an idiot, but I wanted to see what you guys think I should do now and if you think that the motor will be alright.

 

[Laddies]

Re: 2-Stroke 83' Mercury Inline 6

There is a very good chance that the E10 cut the crude loose and now the carbs need to be cleaned and a fuel pump kit installed.

 

[dwyork@hotmail.com]

Re: 2-Stroke 83' Mercury Inline 6

Well, that definitely makes sense. How should I go about cleaning my fuel system since I ran some really old fuel through it? Is there anything else that you guys think I should do to get the boat ready for spring fishing and do you think that a carb rebuild and new fuel pump will get me running again?

 

[Laddies]

Re: 2-Stroke 83' Mercury Inline 6

I would drain the fuel tanks and hoses and rinse with fuel. The old fuel if it smells OK and can be strained and ran in a lawnmower, etc. At that point remove the carbs and install a fuel pump kit. It is very important to flush all lines of debrie or they with send more crudes back to the carb and you can start again.

 

[dwyork@hotmail.com]

Re: 2-Stroke 83' Mercury Inline 6

Thanks for the advise...I will folow your instructions. My first compression check numbers I believe were skewed as I was using a bad battery. I bought a new battery today and re-checked and my compression was as follows: #1 - 105, #2 - 102, #3 - 119, #4 - 101, #5 - 109, #6 - 109. There is some pretty large gaps inbetween these numbers. Do you think that by following your advise that I can regain acceptable compression back? I also found that one of the spark plug wires was badly corroded so I replaced it. The motor will actually start in neutral now where it would not originally. It runs great in neutral and low idle, but once I start to idle up it starts missing a little - but I am running it with muffs on new gas mixed with some seafoam to help clear out some carbon.

 

[Laddies]

Re: 2-Stroke 83' Mercury Inline 6

It sounds like your making headway you might run some powertune or someother brand of decarbining fluid through it to see if that will even out the compression a little.

 

[dwyork@hotmail.com]

Re: 2-Stroke 83' Mercury Inline 6

I will try out some Powertune tomorrow...where is the best place to pick that up from.

 

[Laddies]

Re: 2-Stroke 83' Mercury Inline 6

Powertune is a Mercury product almost any decarbonizer will work to free the rings.

 

[dwyork@hotmail.com]

Re: 2-Stroke 83' Mercury Inline 6

Perfect...thank you so much for all of your sound advise.

 

[hkeiner]

Re: 2-Stroke 83' Mercury Inline 6

I am running it with muffs on new gas mixed with some seafoam to help clear out some carbon.

You did not indicate how much SeaFoam you added to the fuel. The amount added to the fuel is important. If you only put in the recommended amount needed as a fuel additive (say 1 can per 12-20 gallons) that is not enough to decarb. It is suggested to mix 1 can per gallon of fuel to get effective decarb action. Using a portable tank to do this is a good idea, as you only need a gallon or two of mix to do a decarb. Don't forget to add oil (50:1) to the mix as well if you do not have oil injection. Search this forum for more detailed guidance on decarbing, if you need it.

 

[dwyork@hotmail.com]

Re: 2-Stroke 83' Mercury Inline 6

In a portable tank I mixed 1 gallon of gas w/oil with 1 ounce of Seafoam as per the directions and it was smoking quite a bit. So to help in the decarbing process I should put the whole pint of Seafoam in with one gallon of gas/oil mix and run the whole gallon through?

 

[hkeiner]

Re: 2-Stroke 83' Mercury Inline 6

Yes, one can SeaFoam per one gallon of fuel is the dosage I use for decarbing. Read the below linked FAQ and search this forum for "Seafoam" and "decarb" and you will find a variety of methods suggested, including the use of Deep Creep (spray version of SeaFoam) for spraying into the carb throat with engine running and into the spark plug holes with engine off.

http://forums.iboats.com/showthread.php?t=158076

 

[shanew]

Re: 2-Stroke 83' Mercury Inline 6

Other things to consider, the engine is a six cylinder with three carbs, if one carb is plugged and no fuel/oil mixture is getting to those two cylinders, it will run but it could lead to disaster. It is just good advise to have the carburetors removed and cleaned. And like previously mentioned the complete fuel delivery system needs cleaned. Thats everything from the filler neck to the three circuits in the carburetors. Also, don't forget the lower unit. Change that oil, check for leaks, look for fishing line on the prop shaft. Change the water pump impeller, and if you can afford a water pressure gauge, install one. The boat is new to you, now is the time to make sure everything is working correctly. Remember, there is nothing that will ruin a good day of fishing like having to work on the boat instead of throwing lures. Good Luck!

 

[dwyork@hotmail.com]

Re: 2-Stroke 83' Mercury Inline 6

So after I rebuilt the carbs and fuel pump and tested the fuel system I moved onto the electrical and ignition side of things. I rewired the entire system, replaced the switchboxes and it still ran horribly. It would idle well, but it would start to bog down and surge around 1500 RPM. So I replaced the plugs, plug wires, and tested the coils as it seemed that I wasn't getting very good spark. I was getting ready to replace the Stator when I decided to try and run her with the rectifier disconnected and to my amazement she ran perfectly. She went from only running at 1500 RPM at about 5 mph to running 40+. The funny thing is that I tested the rectifier on multiple occasions per the manual and forums and the test results showed the rectifier as good. But anyway she is running perfect now and I am soooooo Happy...thanks for all of your help - there is no way I could have broken down the process of elimination without the help of this forum.