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sdrew22

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Hello all, I am coming to you for help as I have exhausted all other options. I appreciate your time.

I recently acquired my first outboard motor. A 1972 Johnson Seahorse 2Hp ( 2R72M). The motor has been in a barn and untouched for 35 years. I brought it to my Marina and had them perform a tune up. New fuel lines, cleaned the carb, etc. The motor runs great. Starts right up and will run for hours. The problem I am having is that it will not go faster than idle. My current average speed is below 1 mph. At times I will see a brief surge and will see a top speed of 4.5 mph, but this only lasts for a few seconds. I have no clue what the issue is here. Any help will be greatly appreciated.

Mixture- I have a 2.5 gallon gas can. I use a 6.4 oz bottle of 2 cycle oil. 50:1 ratio. The instructions on the bottle of the oil say to dump all 6.4 ozs of oil into 2.5 gallons of fresh fuel. The gas tank on the motor is extremely clean. I have used non ethanol fuel and have tried regular 87 with Startron stabilizer. I am having the sames issue regardless

I have run tank after tank of fresh fuel and am not seeing any improvement. I have also changed the spark plug numerous time.

Boat- I will be using this motor on my canoes. All are under 90 pounds unloaded.

Thanks!
 
Did they put in a new ignition coil ?----If not I would be inspecting this old coil.----Likely cracked like all of them.
 
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Yes, check coils. When you are under there check the points. Are they gapped too big? Does closing the choke any amount help or harm?
 
The symptoms are classic for running on one cylinder and the other one cutting in and out on occasion. But there is a major problem with that diagnosis. A 2hp only has one cylinder. I'm very interested in how this turns out, keep us posted.

Probably not the problem but is the ground wire connected between the block and magneto plate?
 
Quick update. I have been traveling so I havent had a chance to play with the ignition coil. However, I took the motor out this morning and was having the same issues, but as I was troubleshooting I turned the fuel off via the petcock and once I did that the motor came roaring back to life. And then died once it used up all the residual fuel . Any idea why this would happen?

Once I open the fuel back up I have the same symptoms as above.
 
Leaking float valve.----Clean the carburetor.-----Labor charges add up quickly.----Have an invoice here where someone was charged 16 hrs for diagnostics and repair efforts on a 1965 model Evinrude 60 HP.-----That was at $135 / HR and it still was not running properly.
 
OR----Have you tried adjusting the high speed mixture knob (the lower one)? It could just be set too rich. Try turning it to the right and see if it smooths out and takes off.
 
You can not give up on this. I need to know now how this story ends! Does it have high low adjustment screws! Is it possible that one of them feels bottomed out but was not so adjustment is way off on the high speed? Along those lines, for my 4hp and 5.5 there little delicate washers that go in to the orifices for high and low speed. These could easily be damaged. if they are, they could partly clog the orifice preventing the right fuel mix...
 
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