Much maligned, "dirt in the carb" is usually NOT the source of your outboard ills, UNLESS you left last year's gas in the motor. If you suspect that the carburetor is dirty, or blocked, there is an easy way to get an idea of what's going on inside. Almost all modern carburetors have a screw plug on the lower portion of the float chamber which gives access to the main high speed metering jet(s). Remove the plug/screw and examine the end of it. If it is clean and same color as the rest of the screw, your carburetor is probably OK. Coated with brown stuff? Full of tarlike, smelly, green gooey junk? White powder or a jellylike clearish glop? You're in trouble, bunky! Remove, disassemble and take corrective action.

Suspect that one cylinder is running lean at idle? Motor coughing back at low speed? Get out your propane torch and, unlit, open the valve in front of your carb(s). The one that's too lean will smooth out, as the propane will richen the mixture and you can then take corrective action.

Have a particular cylinder not receiving fuel? Remove the screw in front of the high speed jet, usually located on the lower front of the carburetor float bowl. Look in the area inside where you removed the screw with a flashlight to see if there is a fragment of dirt lodged in the orifice of that jet. Many times this can be cleared by simply priming some gas through to rinse it out. If you are unsure, or no luck, take it off, disassemble and blow it out with compressed air.

If you find the fuel system varnished, you have your work cut out for you. Remove and soak clean the entire carburetor array, not just one. DON'T use harsh stinky automotive cleaners. This stuff will take the hide off you as well as ruin your carb(s). Obtain a quantity of Evinrude-Johnson Engine Tuner or Merc Power Tune (I'm sure there are other sources), available in spray cans and gallons; submerge the disassembled carburetors in it for a couple hours to overnight depending on how bad the goo is, agitating occasionally. Rinse with plain water, and blow out passages with compressed air.

Remember, you are dealing with a complete system, not just the carburetor & contents. REPLACE the hoses and the fuel pump diaphragm! Attend to the fuel hose and tank as well, they will more than likely be cruddy also. A new fuel line with bulb and fittings is cheap insurance here, especially if you have an old neoprene hose which by now is rock-hard from plasticizer depletion from "modern" fuels.

If you need parts for your carburetors, fuel pump and associated components, be sure to check the fuel system pages for your Manufacturer here on site; we can probably arrange to supply you with the parts you need right away. We have access to kits for most modern brands of outboards, and can refer you to the right source for older models. There is a plethora of differing components, so contact us today for help if you can't locate what you need on the site.

  The motor cover is a machinery guard. Use caution when conducting tests on a running engine.  

IF you wish to service or repair your own fuel system, I HIGHLY RECOMMEND you obtain an OEM model-specific service manual to help you. We have most linked Right Here at Mastertech.

 

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