9.9HP Honda 4 stroke. The 'tell tale' pipe is often blocked when I go to the boat, on her mooring?

Question

It came with an old yacht. During the first year of my ownership, the blockage was where the pipe exits the lower metal casing, and sprays out. (This was easily cured with a long safety pin.) The next year, it started to block where the water leaves the engine block. (Where the inner end of the flexible pipe pushes on and is held by a small clip.) That was easily cleared by pushing a thin screwdriver in as far as it will go(about 2"-3".) This year niether of those tricks are working. Is there anything I can try? I had the engine professionally serviced when I bought the boat, but the problem started the first time I used it.

I am not convined that the impellor has a problem. Is there any way I can check, without stripping the engine down? (Which is a daugnting prospect.) Tomorrow I intend to run it in a large bucket with a thermometer attached (strapped on) but cannot find the operating temperature in the handbook. Any ideas on the normal operating tem[perature?

Answer 1

If this motor is being used in salt water, you should flush it with fresh water after using it.  Get an old flexible speedometer cable,  poke it into to pipe through the corrosion and push it back and forth to clear the side walls.   Then use a hose to flush fresh water through after use. The normal operating temp is 160 to 180 degrees F.

Answer 2

Sorry I don't have any experience of  these engines, but whatever you do, DO NOT USE CAUSTIC SODA as it will severely damage any aluminium parts of your engine!

Answer 3

Geez! Caustic soda? Please!!! OK, the "tell tale" is an indicator of w/p pressure. The block fills to the top, and then "pees" out the tube. if it isn't peeing, try using compressed air to blow out the tube. If this doesn't work, take it to a dealer. Probably more simple than you think.

Answer 4

Hi if you can get some caustic soda through the cooling system if you can . or if you going to run it up try doing it in a barrel of water with the prop off of course it sounds like your cooling holes are blocked up with lime .

Hope this helps

Answer 5

Try using a length of wire to clean the "p" hole.  It will reach deeper than a screwdriver.  Of course if you try to clean the intake be careful of the screen.  I have never seen a published operating temp but an old rule of thumb is, after the motor is up to operating temp, if you can put your hand on the side of the block without pain the temp is close to right.  DO NOT use caustic soda on aluminum parts unless you want to get rid of them.