7.5 Evinrude and original fuel tank

CreekRunner

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Aug 31, 2010
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Was just given 50's era 7.5 hp evinrude and original pressurized fuel tank. Couple questions-
1) Fuel tank leaks around primer shaft (metal knob). This is a three gallon Cruise-a-day Junior tank. Are repair parts available?
2) Engine sitting outdoors for 10 yrs. Still turns over. What precautions and preventions required prior to attempting start?
Thanks in advance.
David
 

1946Zephyr

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Oct 21, 2008
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5,556
Re: 7.5 Evinrude and original fuel tank

That is actually a 4 gallon tank and mix 1 quart of TCW-3 outboard oil with one full tank of gas (16:1) Spark plugs are J6C that set at .030 and points set at .020.

Rebuild kites for your tank are available at vintage outboard dot com. Tune up kits and waterpump impellers are available here at iboats.
 

F_R

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Re: 7.5 Evinrude and original fuel tank

Rain or sea water gets down into that primer pump through the push button hole. Once in there, it rusts the diaphragm support washer and rots the end of the push button rod. There is a nut on the bottom of the rod, and if it comes loose, that will make it leak also. Any of these can cause fuel to leak out, as also can a simple rotted diaphragm problem. Point I'm making is take it apart and inspect it before ordering parts.
 

CreekRunner

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Re: 7.5 Evinrude and original fuel tank

Have assembly apart already. It appears to be a dry rotted diaphragm. I can get one local I think and a new cork gasket to go back to tank.
Does stem on primer rod have an o-ring also or is diaphragm only separation from gas in tank?
David
 

F_R

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Re: 7.5 Evinrude and original fuel tank

The parts I just mentioned also separate the areas. Gas can go through even a new diaphragm---that is through the push rod hole if the support washers and end of the push rod are not in good condition.

One other thing I didn't mention is that the button is supposed to spin freely on the rod. If it doesn't spin freely, there is a tendancy to rotate it as you mash down on it, and that will rotate the rod, unscrewing the nut.
 

HighTrim

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Re: 7.5 Evinrude and original fuel tank

Post some pics if you can, we love to see these old girls.

Sitting as it has, you will likely need a full tuneup, or let me reprase that, you will need a full tuneup.

First thing that I would do is check compression, to ensure all is well with the powerhead before spending any money. I believe all of my 7.5's are in the 80 to 95 psi range, and should be equal between cylinders.

After that is out of the way, time to pull the flywheel and inspect the ignition. Have the coils been changed? You will know right away, if they are cracked and rotted, they are original and will cause immediate trouble, change them. Would also be the time to refresh the points/condensors. These parts are available just about anywhere. While the coils are out, change the plug wire with new copper core wire, available at your local NAPA.

Once the flywheel is retorqued, time to clean/rebuild the carb. This would include new fuel lines, as the old ones will be cracked/rotted and not ethanol resistant. Let us know if you need help with this.

Now it is time to drop the lower unit, and change the impeller. You will need to pull the powerhead to do this though, not a big deal, we can walk you through it.

Once bolted back up, change the gearcase oil and she will be good to go for another number of years.

If you need help with manuals, PM me. Post your model number so we can give more specific instructions.

Good luck.


Once the
 

CreekRunner

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Re: 7.5 Evinrude and original fuel tank

Thanks guys. Picked up new diaphram and cork gaskets for fuel tank today locally. I will post some pics of the "project". Thanks Chris, the step by step stuff is a great help. And on manuals, I was given an operators manual that came with motor. I have misplaced it but will find it. What other manual(s) would I need, service, parts,etc.?
 

HighTrim

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Re: 7.5 Evinrude and original fuel tank

Yes a service and parts would be of help. What is the model number of the motor?
 

CreekRunner

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Re: 7.5 Evinrude and original fuel tank

OK guys heree are a few pics I hope. New at this so bear with me.

And I can't seem to locate a model/serial number. Any advice on where it's located?Cowl.jpgmotor1.jpgTankParts.jpgmotor2.jpgmotor3.jpg
 
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