fuel pump

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mrk_cdk

Recruit
Joined
Jul 4, 2001
Messages
3
I have a 1963 75hp evinrude i just rebuilt the carburators and took it out it idles fine but when you try to get it over an idle it has alot of problems (spitting and spuddering) if you pump the fuel bulb it will start running fine could it be my fuel pump and if so is there any way to put an electric fuel pump on any advide would be greatly appreiciated thanx marty
 
12Footer

12Footer

Fleet Admiral
Joined
Mar 25, 2001
Messages
8,217
Re: fuel pump

The fuel pump works off off compression, so run a compression test. I don't know what normal compression is, but look for equal compression on all cylinders.<br />And an old girl like that probably could stand a rebuild of the pump. But before tearing into it, make sure you can get the replacement diaphram.
 
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fg

Cadet
Joined
Jul 3, 2001
Messages
7
Re: fuel pump

This may be a stupid question (I am just learning), but since the pump runs off of compression, and the engine needs fuel to run--how do you test compression AND run the engine?
 
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Walter

Senior Chief Petty Officer
Joined
Jul 3, 2001
Messages
787
Re: fuel pump

I believe the procedure goes something like this:<br /><br />Install the proper compression test gauge into one of the spark plug holes. Crank the engine over with the starter long enough to get an acurate reading and and record the result. Repeat procedure for each cylinder. It is not necessary for the engine to actually run...infact, I'd say it's probably best that it doesn't. On newer engines...I'd flip the "kill switch" to prevent the engine from starting while cranking. It's not too likely your older Evinrude has a kill switch though... If you test when the engine is cold and you don't choke it...I doubt it would fire. Good luck...be safe.<br /><br />Walt
 
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fg

Cadet
Joined
Jul 3, 2001
Messages
7
Re: fuel pump

How about for a 2 cylce with one plug? Or does the fuel pump run off of something other than compression?
 
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crazyray

Petty Officer 2nd Class
Joined
Jun 19, 2001
Messages
134
Re: fuel pump

1st to perform compression test remove all plugs first.....2nd yes even on an 1 cylinder motor it still uses compression to pulse the fuel pump
 
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wwebb

Recruit
Joined
Jul 6, 2001
Messages
2
Re: fuel pump

on some motors when you have a leak of the fuel pump diaphram it will let fuel leak into the crankcase and cause the lowest cylinder to became flooded.
 
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GETDANET

Seaman
Joined
Sep 20, 2001
Messages
58
Re: fuel pump

in the senario of the fule going into the bottom cylinder ,would that caus eit to foul out and also have a miss?????
 
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seajay

Seaman Apprentice
Joined
Nov 17, 2001
Messages
40
Re: fuel pump

i would also check pickup tube in fuel tank,also check fuel line for pin holes or cracks,you may be loosing prime.
 
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Fouled Plug

Ensign
Joined
Jun 29, 2001
Messages
935
Re: fuel pump

Mrk_cdk, please don't try an electric pump. It sounds like a nasty fire waiting to happen! The factory pump is a good design, and a rebuild kit would be cheaper than a conversion anyway. :)
 
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