Hard time starting my 73 115hp Johnson

teslaman

Petty Officer 2nd Class
Joined
Aug 5, 2006
Messages
196
I recently installed brand new park plugs (surface gap type) and have ran the engine without trouble. However, when I went fishing this last weekend, I couldn't get it to start. Luckly, another fisherman told me that the spark plugs might be wet so it might be good to tkae them out and wipe them off.

When I removed the spark plugs they were covered with goop (unused gas/oil or carbon). The goop had bridged the gap in the plug so that the spark plugs wouldn't work. After wiping the goop off of the plugs th engine started rather effortlessly. My question is, is there a way to clean the crap from inside the engine without taking it apart? I'm using a 6:1 ratio like the manual says and I've even ran STP fuel system cleaner. Of course, I'm switching spark plug types to help avoid this problem later.

Last time I took it out I disconnected the fuel line and ran the motor out of fuel. Is this a good thing to do to the engine? I've heard the fuel mixture will form a varnish on the interior parts of the motor.
 

Xcusme

Commander
Joined
Apr 21, 2003
Messages
2,888
Re: Hard time starting my 73 115hp Johnson

A 6:1 ratio? I'm hoping that was a typo.!!...
You should be running a 50:1 gas to oil ratio. Typically 6 gallons 87 Octane gas with 16oz. of TCW-3 oil.
 

dsinger

Chief Petty Officer
Joined
Aug 6, 2004
Messages
424
Re: Hard time starting my 73 115hp Johnson

Seafoam in the gas tank and then Deep Crep in the cyllinders let set for 20min or so while the motor is hot. Restart and stay up wind. The way I do it is to allow the motor to warm up then flood it with deep crep throught the carbs. Then pull all the plugs and fill each cylinder with deep crep or sea foam in a spray bottle which everone I have. Let set 15 to 20 min or so then starter up. Do this two or three times just depends on the amount of carbon I am burning. I then go stright to the lake and run it at WOT for a while. I also add seafoam in the gas throughout the year off and on.
 

teslaman

Petty Officer 2nd Class
Joined
Aug 5, 2006
Messages
196
Re: Hard time starting my 73 115hp Johnson

Sorry, I meant 1 pint of oil per 6 gallons of gas.
 

teslaman

Petty Officer 2nd Class
Joined
Aug 5, 2006
Messages
196
Re: Hard time starting my 73 115hp Johnson

Ok, I looked at the decarb instructions on the link sent by Fleet Admiral. If I spray the seafoam in the cylinders and let it set over night. Do I need to leave the cover off when I take it to the lake the next day?

I read that this can be pretty messy.
 

teslaman

Petty Officer 2nd Class
Joined
Aug 5, 2006
Messages
196
Re: Hard time starting my 73 115hp Johnson

If I spray the seafoam into the carbs and cylinder wells the night before, when I take it to the lake the next day and run it do I need to remove the engine cover? I would assume that most of the stuff goes out the exhuast but I wanted to be sure.

Thanks

rickdb1boat said:
I would do a decarb. first:

http://forums.iboats.com/bbBoard.cgi?a=viewthread;fid=36;gtid=1035563 ] Decarb[/url]

Run QL77JC4 spark plugs gapped at .040


Run 50:1 fuel/oil mixture....1 pint of oil per 6 gallons of gas...
 

rickdb1boat

Supreme Mariner
Joined
Jan 23, 2002
Messages
11,195
Re: Hard time starting my 73 115hp Johnson

Yep. Treat the motor and take her out on the lake and run her out good to blow the carbon out. Leave the engine cover on as the gunk will be coming out the exhaust....
 

teslaman

Petty Officer 2nd Class
Joined
Aug 5, 2006
Messages
196
Re: Hard time starting my 73 115hp Johnson

Thanks for the tip. I found the seafoam products on the iboats site, but their out of the deep creep. A local merchant carries the quicksilver version of seafoam and deep creep, would those work as well as the seafoam brand?
 
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