'71-'72 9.5 hp evinrude wont run with out choke

casey_smith193

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Jan 18, 2013
Messages
5
In addition to the title, no response when throttle is twisted. Jets are all clear. Disassembled carb and throughly cleaned. When running with choke, you can push the choke plate down a bit and let it up and it revs up. Could it be the fuel pump?
 

Joe Reeves

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Feb 24, 2002
Messages
13,262
Re: '71-'72 9.5 hp evinrude wont run with out choke

Sounds more like you're overlooking something within the carburetor. Closing the choke slightly etc makes a change in the rpm... this proves that there is fuel in the carburetor.

Did you actually clean the brass high speed jet located way in back of the float chamber drain screw/bolt? A fouled high speed jet is the most common problem that results in the problem you describe. clean it thoroughly with a piece of single strand steel wire.
 

casey_smith193

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Joined
Jan 18, 2013
Messages
5
Re: '71-'72 9.5 hp evinrude wont run with out choke

Yes I cleaned the high speed jet with wire and also carb cleaner. I am also convinced it is something in the carb. Just thought I would ask about the fuel pump
 

Joe Reeves

Supreme Mariner
Joined
Feb 24, 2002
Messages
13,262
Re: '71-'72 9.5 hp evinrude wont run with out choke

You could check the fuel pump for a cracked diaphragm as follows (below).... and note that pumping the fuel primer bulb is in effect acting as a manual fuel pump. If pumping the fuel primer bulb causes the engine to run properly, then somethiing is not right with the small fuel pump BUT if pumping the fuel primer bulb makes no difference, then that would indicate a carburetor problem.

(Fuel Pump Diaphragm Test)
(Two Hose Type Only)
(J. Reeves)

Note: This pertains only to the regular Two Hose type fuel pumps.

Leave the hoses attached to the fuel pump. Remove only the two screws that attach the fuel pump to the powerhead. Re-insert those two screws and install a nut to each of them so that the fuel pump is securely clamped together. With the fuel line attached to the engine, pump the primer bulb while observing the pressure/vacuum operating hole on the back side of the fuel pump. Should any fuel leak out that hole, the diaphragm is faulty.

If the diaphragm is faulty, the fuel pump will require rebuilding or replacing. Note that repair kits are not available for all fuel pumps, in which case replacing the pump would be necessary.
 

Willyclay

Captain
Joined
Sep 8, 2006
Messages
3,239
Re: '71-'72 9.5 hp evinrude wont run with out choke

Good info at the link below if you have not already fouind it! Good luck!

Johnson
 
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