flushing or backflushing a outboard for clear water passage

licketdsplit756

Petty Officer 1st Class
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Jun 15, 2007
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318
1988 140 hp johnson ob has the lower unit off and a new water pump completely rebuilt. before this work was done there was no water comming out of the little hole in the motor housing. like a relief hole or something.maybe it was the pump? not sure but want to run water thru the system before installing lower unit to be sure it is clear of any blockage there might have been. ive seen where some motors have a flush nozzel in the mid section mine is just two 1/2 square holes in the back side of the motor.? then im done and gone fishing. i hope
 

HighTrim

Supreme Mariner
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Jun 21, 2007
Messages
10,486
Re: flushing or backflushing a outboard for clear water passage

Run compressed air or the garden hose up the water line, ensuring it exits at the t stat housing, then back down, ensuring it exits via the water line. Also be sure that the water intake area is free of debris.

Also be sure that the tell tale water line and nipple are free of obstructions. Little critter love building nests in here.
 

ezeke

Supreme Mariner
Joined
Sep 19, 2003
Messages
12,532
Re: flushing or backflushing a outboard for clear water passage

The 1988 140 is a big bore looper that came with a tell-tale, overboard indicator or whatever you may call the pisser. It should be connected to the adapter plate and exit through the starboard lower cowl.

See the picture of mine by clicking the thumbnail.
 

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licketdsplit756

Petty Officer 1st Class
Joined
Jun 15, 2007
Messages
318
Re: flushing or backflushing a outboard for clear water passage

ty that is the exact pic there. water should flow out the hole soon as the motor starts. ill flush it first. before i let it run for about 30 sec. and shut it down because there was no water present. should i give it a little more time. this motor is new to me. so im not to familiar with it.
 

ezeke

Supreme Mariner
Joined
Sep 19, 2003
Messages
12,532
Re: flushing or backflushing a outboard for clear water passage

It should flow pretty quick. The water pump is not self priming, so if you are running on muffs, you have to wait until you see the water coming out near the bottom of the midsection before you start the engine. If you are in the water, the gearcase needs to be totally submerged.

The water outlet for the tell-tale is only 1/8" NPT so that particulate will clog it easily. If the intake screens on the gearcase are broken or missing, the tell-tale outlet will get clogged repeatedly.
 
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