# Time to get the motor running...



## cmatthews_jm (Mar 4, 2011)

So my dad and I have an evinrude 15 hp 2 stroke that has been sitting for at least a year i know. We have plans to get it out this weekend and try the motor to see if its still running. It isnt a new motor by any means but its got a metallic blue shaft, white cover head with blue and white text. Ill update with a year when I find it. There wasnt any Stabil put in it and I dont know if that matters. I guess what I'm asking is is there anything I should do before cranking it and if it doesnt crank this weekend what should I do after that...?


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## cmatthews_jm (Mar 4, 2011)

I think it's close to an '87 model





Kinda like this, this isn't the motor but the best I can find for right now.


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## crazymanme2 (Mar 4, 2011)

Model # & I can tell you what year it is.
As far as the motor goes I would put a little 2 stroke oil in the spark plug holes, turn it over a few times before putting plugs back in,replace water pump impeller,check lower unit oil,than see if it runs.


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## Bobg (Mar 5, 2011)

Good tips from above, and also empty and clean out the gas tank. Don't use stale gas/oil mix. It's worse than ever with todays ethanol gas.

Phase separation,

In the case of two-stroke4
engines, this water-ethanol phase will compete with the blended
oil for bonding to the metal engine parts. Therefore, the engine
will not have enough lubrication, and engine damage may result. 
In the case of four-stroke engines, the water-ethanol phase may
combust in the engine. This combustion can be damaging to the
engine because the water ethanol phase creates a leaner
combustion mixture (i.e. air to fuel ratio is higher than ideal). 
Leaner mixtures tend to combust at higher temperatures, and can
damage engines, particularly those without sensors to calibrate
air to fuel ratios.

Phase separation, happens when the ethanol bonds with water and settles out of the gasoline to the bottom of the tank leaving the oil behind.
Can old gas be the cause of a blown engine? Answer: YES!!! It was a test question in marine tech school, years ago.

Two reasons, lack f lubrication, and as mentioned above, a lean gas to air mixture creating higher than designed cylinder head temperatures, which can lead to detonation, or preignition. Both damages a piston.


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## cmatthews_jm (Mar 6, 2011)

Good thing the battery is dead so I couldn't get the motor testable this weekend. What is the best way for me to get the tank cleaned out without blowing something up? Or could I just buy a new tank and start new?


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## Bobg (Mar 6, 2011)

Blowing something up? You plan on lighting a match and looking in the tank?
I refuse to believe that people are as dumb as the government wants us to believe. You know it's flammable, take proper precautions.

Just dump it out into a 5 gallon bucket, then into a proper container to be used in lawn equipment, mixed with fresh gas.

Look at the tank and remove anything you can remove from it, cap, pick up tube, or fuel gauge if it has one. Stuff a few paper towels in it, push them around with a long stick or screw driver, then pick the towels out. Repeat the process until the tank is clean and dry. No rocket science involved here.

If you have a lot of sludge laid up in the bottom of the tank, just pour in some pure ammonia, cap it, and clean it the next day.


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## cmatthews_jm (Mar 6, 2011)

I mean i knew it wouldnt blow up but i was just curious, I mean who doesn't like a good show of fireworks?  but thanks for the help.


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## Lil' Blue Rude (Mar 6, 2011)

Bobg said:


> Blowing something up? You plan on lighting a match and looking in the tank?
> I refuse to believe that people are as dumb as the government wants us to believe. You know it's flammable, take proper precautions.
> 
> If you have a lot of sludge laid up in the bottom of the tank, just pour in some pure ammonia, cap it, and clean it the next day.


Hey, I went to shcool with a couple of kids that pulled a stunt about like that. They went giggin one night, the boat owner and his freind was on the deck. The smart one driving didn't have a light to check the gas in the generater for gas so he used his lighter. The vaper lit off and he managed to gt it put out before it blew up. Yep he was a smart one. :lol: :lol:


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## cmatthews_jm (Mar 14, 2011)

I figured out the model number and the year the motor was made. The year model is a 1978 15hp Evinrude and the model number is 15804B if that means anything you yall. Anyone have any advice or recurring problems they know of with this model? 

Also, I figure out this weekend that the pressure bulb was dry rotted and sprayed gas every time it was squeezed. So I'm thinking that I want to replace the entire gas line and ball just to know everything in that department is safe.


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## BassBlaster (Mar 14, 2011)

Heres a website with about anything you would ever want to know about your motor.

https://www.sschapterpsa.com/ramblings/Johnson%209.9_15.htm


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## Bobg (Mar 15, 2011)

Definitely replace that whole fuel line and bulb.


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## Bobg (Mar 15, 2011)

Bobg said:


> Definitely replace that whole fuel line and bulb.


 Take off the gas line to the carb and purge the system with fresh gas and reinstall the gas line.


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## cmatthews_jm (Mar 15, 2011)

Im thinkin it may be a good idea to rebuild the carb...anyone second that?


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## Bobg (Mar 16, 2011)

Sure, it's easy on that model. If everything is tuned right, and your hand is big enough, you can twist that flywheel quickly and the engine will start.


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## cmatthews_jm (Mar 17, 2011)

Sweet, since I don't have any money right now everything is put on hold. However, there is a good possibility that by mid summer the boat will be running like a champ :/ But I'm really trying to get everything in a 'to do' list so make sure that I get everything done right. I'm not a pro or very experienced at all at motor repair or anything so I'll probably end up posting more questions as I find them and get the money to work on the stuff. Thanks for all the advice and any more anyone has is always appreciated.


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## cmatthews_jm (Aug 9, 2011)

After being gone for a while and working/sweating my butt off this summer, I finally get to update some progress I made with my boat. I FINALLY GOT THAT MOTOR RUNNING TODAY! Feels good to say that and its strange to think that all it took was some starter fluid in the intake to check for fire and some Sea Foam in the tank to clean the system. And let me tell you there is some gunk in that engine. I Did that first to see if the carb actually needed to be taken out or not for the sake of time. Good thing that right now it doesn't. 

Question though...does anyone have a problem with the old OMC's running 87 grade gas because I was gonna start running high test and wanted to see if there were differences or advantages. Im taking it out on the water tomorrow after work to run it in the water and work the throttle a little more than I could with the flushers on. Anything that you guys have to offer is awesome. 

Thanks you guys and sorry about falling off the forum for a while there.


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## nomowork (Aug 10, 2011)

BassBlaster said:


> Heres a website with about anything you would ever want to know about your motor.
> 
> https://www.sschapterpsa.com/ramblings/Johnson%209.9_15.htm



Good advice. I've used that website myself when I had a 15hp Evinrude.


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## cmatthews_jm (Dec 11, 2011)

So since school started back I have been MIA on this forum. So I guess I was wondering if anyone could answer my previous question and my new question. My previous question was if it mattered to run an 87, 89, or 93 grade gas to mix for a two stroke engine? And my new question is if, after running the seafoam through the engine for a good while, is there a reason that the engine shouldn't start after it sat for a while and is it necessary for me to change the spark plugs as well? I think I should probably change the spark plugs anyway just because I know they haven't been changed for a while. 

Any help is appreciated.


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## rickybobbybend (Dec 11, 2011)

I have a '79 'Rude 9.9...it is a reliable motor. I have always been more concerned with avoiding ethanol than the specific octane rating, so long as the fuel was fresh and at least at minimum recommended octane. In my area ethanol- free is only available in higher ratings, and It runs just fine. Good luck with your motor, it is a good one.


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## cmatthews_jm (Dec 12, 2011)

Anyone know about replacing the spark plugs after running seafoam in the gas?


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## Canoeman (Dec 13, 2011)

Depends on how they look.. if bad either clean them up with sand paper and a torch or replace.


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## cajuncook1 (Dec 14, 2011)

cmatthews_jm said:


> Anyone know about replacing the spark plugs after running seafoam in the gas?




Your motor was design to run on 87 octane at fuel/oil of 50:1. 

If the spark plugs were in good shape prior to the Seafoam decarbing, then they will be fine after the decarbing. Naturally they will be junked up, but just clean/soak the junked up ends in a small tin can of gas. Just stir the tip (in the gas) like you would if you were briskly stirring a mug of hot chocolate. When the junk is off, then rinse the plug with water and lightly sand plugs ends with sand paper to clean them off well. Re-rinse with water and dry the plug very well. *Good as new!* (come on, they are just spark plugs :LOL2: )

If the plugs have been in for a long time, then get a new set of plugs, they are probably $6 or $7 at most for a pair.


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