Outboard Carburetor Repair Tips
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.
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 thats too lean will smooth out,
as the propane will richen the mixture and you can then take corrective
particular cylinder not receiving gas? 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
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 OMC or
Merc "Engine Tuner"(I'm sure there's 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.
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 page for your Manufacturer here on site; E-mail or call me, I 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 call today for help.
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 available Right Here at Mastertech
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