7.5 Evinrude and fuel tank

CreekRunner

Seaman Apprentice
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Aug 31, 2010
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42
Going to re-build tank today. Can't seem to get diaphram gasket off of fuel level sight glass, would this just be well stuck or maybe glued? Primer rod has mechanical fastener with washers and nut it seems.

Also going to do comp test on engine. I have the gauge I bought for another engine years ago. It cranked over with a starter.

I would guess remove plugs, spray a little oil in cylinder(or test dry),install guage, Pull rope to turn engine over two or three times to get true reading?

Someone said comp should be 80-90 on each cyl. How about tolerance between the two?

Thanks for the help folks.
 

64osby

Admiral
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Jul 28, 2009
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6,799
Re: 7.5 Evinrude and fuel tank

Going to re-build tank today. Can't seem to get diaphram gasket off of fuel level sight glass, would this just be well stuck or maybe glued? Primer rod has mechanical fastener with washers and nut it seems.

http://www.marineengine.com/parts/v...evinrude-johnson/ITEM_2831/ITEM_283100001.htm This will give a good look at your parts. I'm assuming this is a pressure tank.

Also going to do comp test on engine. I have the gauge I bought for another engine years ago. It cranked over with a starter.

I would guess remove plugs, spray a little oil in cylinder(or test dry),install guage, Pull rope to turn engine over two or three times to get true reading?

Test after squirting w/ pb blaster or some other type oil / lube

Someone said comp should be 80-90 on each cyl. How about tolerance between the two?

Your looking for 10% difference or less

Thanks for the help folks.

You didn't state the year or model number of your motor.

Have fun!
 

CreekRunner

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Aug 31, 2010
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42
Re: 7.5 Evinrude and fuel tank

Got tank disassembled, cleaned and put back together. Sight glass was just stuck to diaphram gasket.

I think it's a 55 ish but still haven't found the serial no. It's dark when I get home and no luck yet using flashlight.

Thanks 64osby
 

HighTrim

Supreme Mariner
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Jun 21, 2007
Messages
10,486
Re: 7.5 Evinrude and fuel tank

I do disagree though with oiling the cylinders before the compression test.

You want a baseline for future testing/problems. Oiling will not give you a true reading
 

1946Zephyr

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Oct 21, 2008
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Re: 7.5 Evinrude and fuel tank

It's actually best to use fuel mix to get things lubbed up and working correctly. Just get a bunch in through the carb and pull the rope, till it gets in around all the internals.
 

64osby

Admiral
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6,799
Re: 7.5 Evinrude and fuel tank

My recommendation for oil of some kind is so it wasn't done dry, possibly scoring the cylinders. I tend to not have easy access to premix when I'm working on motors.
 

CreekRunner

Seaman Apprentice
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Aug 31, 2010
Messages
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Re: 7.5 Evinrude and fuel tank

Ok fellows. Appreciate the advice so far. Like I said on previous post, got the tank back together, now for the engine. Finally found the model number I think-7518 and under that 09902-. Started to do comp test today but recoil mecanism would not grab to turn engine over. I will try to remedy this problem next in order to do comp test.
 

1946Zephyr

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Re: 7.5 Evinrude and fuel tank

Oh yea, the Aquasonic name was a give away. They only used that on the 1955 motors. :D
 
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