Water pump works but water stops after engine is warm

1958 Evinrude 18hp..just had waterpump replaced but mechanic states an "O"
ring on top of a tube just under powerhead needs to be replaced. Have to
remove powerhead to get to it and is costly..he estimates $500.00 to do the
work..supposedly the "o" ring swells closed and does not allow water through.
How difficult to do this at home? Does diagnosis by mechanic sound right?
No striper fishing for me this year..in a boat that is..back to my kayak! Thank
you for advice!

Re: Water pump works but water stops after engine is warm

Welcome to iboats. Do you have a manual for your motor. Here it is here.

http://www.laingsoutboards.com/literature.htm

I know the grommet that he is referring to on the water line, but have never heard of it (swelling) , thus blocking water flow. Armed with a manual, the proper tools and this forum, I would tackle this myself. 500 is a little steep. FR is definately 1 of the men you want to talk to, very knowledgeable in the older motors, and he along with the other experts will be best able to guide you.

Re: Water pump works but water stops after engine is warm

There is a grommet that the intake tube fits into and if it has swollen shut you will have cooling issues. I haven't heard of it swelling as it warms, though. It is more likely that you aren't getting enough water in the first place. I don't have the parts manual for your motor so I don't have the part number, but I'm sure its only a few dollars at your dealer. Replace it yourself. $500 is crazy. Also, check all the passages for blockage since you have it off. Does your motor have a thermostat?

Re: Water pump works but water stops after engine is warm

laings has all the parts you need.

Re: Water pump works but water stops after engine is warm

I have one of these w/ elec. start. Don't know of an o-ring, only the grommet that the copper water tube p/up on the foot, when you split the midsection,change impeller, and that the tube goes in (no thermo on mine) and the tube going inside is not going to let the grommet "close up" and restrict water flow that I can see. Only thing I can imagine is that the grommet is disinetegrating / has disintegrated and chunks are apt to restrict flow. Or it is on the top of the tube that goes into the bottom of the block. I may be in wrong area of what mech. is telling. Don't have a parts schematic.

Re: Water pump works but water stops after engine is warm

Now lets see......$500.00 repair.....2 hours labor=$240.00/hr......and $20.00 for parts.....let me know where you live.....I'm going there to open shop.......

Re: Water pump works but water stops after engine is warm

Had a prob like this once....under the head was a aluminum washer you press fit that was rotten ,i saw it when taking off themostat cover and seeing light at bottom of head.

not sure about years ...check with your fingers underhead.

Re: Water pump works but water stops after engine is warm

I would get the manual as stated above and do it your self, if your a little mechanically gifted you can do this job. The 18 is fairly easy to work on, $500 is very steep for this job. Ive got a 63 but i think there fairly close in design. As far as i know there isnt a o-ring there but a rubber grommet that the water tube slides into as stated earlier.i dont think the 58's had a thermostat, FR or Samo would know for sure. The water stops pumping after its warm ???? really doesnt sound like the rubber would collapse considering the age of the motor.(maybe break apart instead ) can you tell in more detail the history of the motor and the recent history. Did it pump any water before the the pump was replaced( if that was possible)???? The more detail the better!