1982 Johnson 115HP outboard

[NewbieEnthusiast]

Can’t for the life of me figure out how to get this thing to run.. It starts, runs for about 30 seconds, then dies.. I have checked all of the fuel lines from the tank to the engine, from the engine to the carb, checked the primer bulb, ect. Everything was fine. Just replaced all 4 spark plugs, replaced every ounce of fuel, and cleaned the carbs and replaced all the gaskets.. Still nothing.. Could really use any advice I can get! PLEASE HELP! **Sidenote** I am very new to boats.. In fact this is my very FIRST boat. Thank you in advance for any and all help offered!

 

[racerone]

Check the fuel pump diaphragm.----And post your compression test numbers.----Very important to do a compression test before spending $ on this motor.

 

[NewbieEnthusiast]

I’ll try this tomorrow and let you know!

 

[NewbieEnthusiast]

Was not able to test compression quite yet.. But I did manage to find out that 2 of my ignition coils are junk. So it’s only running on 2 cylinders

 

[NewbieEnthusiast]

Ran a compression test.. I’m at 50 PSI in all 4 cylinders.. I was told these 2-strokes should also run on 89 or higher octane.. Is there any truth to that?

 

[oldboat1]

Try again. Need a screw-in style tester, screwed in snug. Remove the other plugs, and crank the engine until the needle stops rising. Record the number.

You may need to try another tester.

 

[jimmbo]

I was told these 2-strokes should also run on 89 or higher octane.. Is there any truth to that?

No. They run fine on 87, Make sure to use a TCW-3 Oil at 50:1

 

[havoc_squad]

No. They run fine on 87, Make sure to use a TCW-3 Oil at 50:1

To clarify, the gasoline octane required is dictated by the compression ratio of the engine. You don't need to know the details, just the recommended gas for the current configuration of your outboard.


Which he listed above as 87 octane.

For a stock outboard engine, manufacturers publish that recommended octane and the allowed Ethanol concentration. A rebuilt motor can possibly alter this, so one might need to check with whoever rebuilds the engine what octane is needed before using a rebuilt motor.

Usually people get higher octane gas because they let the gas sit in the tanks unused too long to be used. By that time with E-10 Ethanol gas, they have bigger problems on their hands.

Buying higher octane gas than what you need is just wasting money. Letting un-stabilized E-10 gas sit in tanks for 9 months and not using it up fully wastes even more money because it goes bad and clogs crap up.

 

[jimmbo]

I thought "They run fine on 87" was Pretty Clear

 

[Tassie 1]

Try again. Need a screw-in style tester, screwed in snug. Remove the other plugs, and crank the engine until the needle stops rising. Record the number.

You may need to try another tester.

Plus 1.