evinrude 5.5 runs but max power is too low

[John Gengler]

Evinrude Fisherman, 5.5 hp, 1962. Compression at 75 psi. Rebuilt the carb & magneto, good spark, starts right up, and runs well in the test tank. It would not, however, reach full power on the water pushing a 14′ boat. There was a fair amount of blackish soot around the exhaust port after a trip around the lake (1 hour). I am thinking the carb might need adjusting.

[seakaye12]

Could it be running on only one cylinder?

[frankr]

You said you rebuilt the carburetor.  You did adjust it then, right?

[fleetwin]

Are you sure it is running on both cylinders?  Have you drained/inspected the gear lube?  These gearcases have a pesky shock absorber that likes to expand and bind up the gearcase.  Also, make sure this engine has the correct pitch prop.  The 7.5hp prop looks identical, but has a larger pitch.

[John Gengler]

The motor has new gear lube, points, condensers, coils, carburetor kit, spark plugs, spark plug wires, etc. Both cylinders are firing. It seems to be running too rich at high speed and generating a lot of smoke almost as if the choke was engaged (which it isn’t). I’m going to adjust the high-speed carb control by turning the rod clockwise a bit. I didn’t have enough travel turning the outer mixture control knob, so I’ll pop the hood, remove the knob, and adjust the inner rod by hand.

 

[crosbyman]

purge valve working ?

Joining AOMCI has priviledges 🙂

[frankr]

John Gengler wrote:

The motor has new gear lube, points, condensers, coils, carburetor kit, spark plugs, spark plug wires, etc. Both cylinders are firing. It seems to be running too rich at high speed and generating a lot of smoke almost as if the choke was engaged (which it isn’t). I’m going to adjust the high-speed carb control by turning the rod clockwise a bit. I didn’t have enough travel turning the outer mixture control knob, so I’ll pop the hood, remove the knob, and adjust the inner rod by hand.

 

Well there ya go.  Running too rich and blubbering and smoking.  Adjust the carb and it probably will take off.

[fleetwin]

Yes, you may have to reposition the dial on the needle in order to get the travel you need to lean it out enough.  Or, like you say, you can leave the packing a bit loose and try to adjust it without the knob so it can be turned as much as necessary.

One final question.  Did you have the carburetor apart?  If so, did you inspect the big/thick nozzle gasket or replace it.  The engine will flood and run rich at high speed if that gasket is missing or worn/damaged…

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