New Johnson Owner!!!

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ampedzach

Seaman Apprentice
Joined
Mar 13, 2012
Messages
41
Hey guys, I'm a proud new owner of a 1980 Johnson 115 hp 2-stroke. I have a couple of questions. 1st: Is it normal for it to smoke quite a bit? I've never had a 2-stroke, but I've heard they smoke pretty good. 2nd: Can anyone tell me how to pre-mix the oil and gas??? 3rd: What's the top RPM's on one of these things??

Thanks a bunch! :joyous:
 
HighTrim

HighTrim

Supreme Mariner
Joined
Jun 21, 2007
Messages
10,486
Re: New Johnson Owner!!!

It will smoke some. It is a 2 stroke right. However, if you use a good synthetic oil, and the motor is in proper tune, smoke will be minimal.

Mix the fuel/oil in a seperate container if possible to be able to thoroughally shake it. You want a good mix. I have a graduated cylinder/bottle made by sea sense that does the math for me to tell me how much oil I need based on how much fuel I added. Keeps it simple.

I would think your WOT RPM would be in the 4800 to 5400 depending on prop.
 
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bonzoscott

Senior Chief Petty Officer
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Jul 26, 2008
Messages
745
Re: New Johnson Owner!!!

50:1 ratio - 1 quart oil to 12 gallons of fuel Or 1 pint oil to 6 gallons fuel
 
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ampedzach

Seaman Apprentice
Joined
Mar 13, 2012
Messages
41
Re: New Johnson Owner!!!

Thanks guys. I'll check into that Seasense product. Do you have a part number for it?
 
airman1094

airman1094

Petty Officer 2nd Class
Joined
Mar 30, 2013
Messages
108
Re: New Johnson Owner!!!

I got that mix container at Walmart...I have a 1975 115 Johnson that I just got back running! I ran mine on 25:1 for a bit to ensure she's getting all juiced up again but man does it smoke! 50:1 is the recommended mix! That rig doesn't have VRO on it does it? If so it adds oil to the fuel for you...it's a small tank on the engine if you have one!
 
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ampedzach

Seaman Apprentice
Joined
Mar 13, 2012
Messages
41
Re: New Johnson Owner!!!

airman1094 said:
I got that mix container at Walmart...I have a 1975 115 Johnson that I just got back running! I ran mine on 25:1 for a bit to ensure she's getting all juiced up again but man does it smoke! 50:1 is the recommended mix! That rig doesn't have VRO on it does it? If so it adds oil to the fuel for you...it's a small tank on the engine if you have one!
Click to expand...

It's not a VRO. Mine runs pretty good and I'm super stoked about it! Would 25:1 be good for mine for a little bit or should I just stick with the 50:1? What size boat is your 115 on? Does it pull tubers pretty good?
 
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emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
Re: New Johnson Owner!!!

The factory recommends 50:1 fuel to oil ratio. Stick with that to minimize possible carbon accumulation around the ringsets. That early crossflow tends to drip a little fuel out of the carbs after it is shut off, esp if the engine is tilted up somewhat. That excess fuel accumlates in the bottom of the airbox. When first started back up the next time, the engine sucks that excess fuel back into the bottom cyl for combustion. So, it's common to have a little excess smoke when first started, till any excess is consumed. Your engine is factory rated to run between 4500 and 5500. Current thinking is to prop the engine to run WOT at the top end of that "normal" range, or 5500. Running it under 5000 is considered "lugging" the engine-not recommended.
 
airman1094

airman1094

Petty Officer 2nd Class
Joined
Mar 30, 2013
Messages
108
Re: New Johnson Owner!!!

I've got an 18 ft tri hull...however I haven't got her to water yet:grumpy:...rebuilding the transom and deck! I ran a gallon of 25:1 in the test barrel, now I'm back to 50:1! If yours has been sitting for a while it prob wouldn't hurt to run a bit of 25:1. Emdsapmgr is right about the carbon pileup so keep it minimal at 25:1! I do that with all my 2 stroke engines that I rebuild or revive!
 
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ampedzach

Seaman Apprentice
Joined
Mar 13, 2012
Messages
41
Re: New Johnson Owner!!!

emdsapmgr said:
The factory recommends 50:1 fuel to oil ratio. Stick with that to minimize possible carbon accumulation around the ringsets. That early crossflow tends to drip a little fuel out of the carbs after it is shut off, esp if the engine is tilted up somewhat. That excess fuel accumlates in the bottom of the airbox. When first started back up the next time, the engine sucks that excess fuel back into the bottom cyl for combustion. So, it's common to have a little excess smoke when first started, till any excess is consumed. Your engine is factory rated to run between 4500 and 5500. Current thinking is to prop the engine to run WOT at the top end of that "normal" range, or 5500. Running it under 5000 is considered "lugging" the engine-not recommended.
Click to expand...

Wow, thanks for all the info. I definitely appreciate it! I was wondering if I should use a synthetic blend of oil too? Here's a link to what I'm thinking Star Brite Super Premium 2-Cycle Synthetic Blend Oil - iboats, Would that work for me?
 
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ampedzach

Seaman Apprentice
Joined
Mar 13, 2012
Messages
41
Re: New Johnson Owner!!!

airman1094 said:
I've got an 18 ft tri hull...however I haven't got her to water yet:grumpy:...rebuilding the transom and deck! I ran a gallon of 25:1 in the test barrel, now I'm back to 50:1! If yours has been sitting for a while it prob wouldn't hurt to run a bit of 25:1. Emdsapmgr is right about the carbon pileup so keep it minimal at 25:1! I do that with all my 2 stroke engines that I rebuild or revive!
Click to expand...

As soon as it gets warm enough I'm taking her to the lake. I can't wait to see how she does! Do you have a thread for your restoration?
 
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