BF8A water system clogs every start

[Tom at oes]

I have a 1997 BF8A. Almost every time I use it, I have to go in and clean out the thermostat and passages near it. They always clog with salt. No, it won't happen if I flush with fresh water, but it happens even during the time period when I am out for a day sail - it will be peeing fine when I leave dock, with the whole thermostat area just cleaned out, and by sunset it is clogged, partially or fully. This has happened at least twenty times and is a real pain when the wind dies...and the water flow does, too.

I've had it to the local Honda shop several times, they just shrug and tell me that "yeah, they sometimes hear of problems like this" but they don't know how to fix it. I've replaced the impeller, blew out the water tube up from the impeller, tried greasing the thermostat and passages (so the water won't condense). I've finally taken to rigging up a squeeze bottle of water to attach to the outlet hose and push fresh water through the engine backward after every time I run the stupid thing.

It started several years ago - before that it didn't happen. I don't recall any changes I made to it around the time the trouble started.

Any one have any ideas what is causing this?

 

[jgmo]

My guess is that you have a problem with the hole in the oil case where the water tube passes through. I have found that the case and the tube will corrode BADLY at that "interface" and results in a gross misalignment of the two. If you are seeing what looks like salt particles it may actually be aluminum oxide flaking from that area. I have repaired some like this in the past by building up the area with epoxy (JB WELD) with good results. Doing this requires that the powerhead be removed and the oil case be stripped down. It's about as extensive a repair as you can do on one of these besides a complete overhaul but isn't all that difficult. Just involved.

As a matter of fact, it affords one the opportunity to clean the sump and oil screen as well as re-seal the case and replace the exhaust pipe seal which fail often on these as well.

Probably not the response you were hoping for but it's my best guess.

Good luck.

 

[racerone]

Flushing is a good idea , but not practical if you have to take the motor off a sailboat each trip.

 

[Tom at oes]

jgmo,

Thanks for the reply. You are right - I hope you aren't right. I think it is salt for two reasons - 1) It tastes like it, although perhaps the aluminum corrosion is just staying salty after being immersed in salt water. 2) The other is that the area where the salt/corrosion build up worst, around the thermostat, stays as a moist paste which is consistent with high salt content. But then, I don't have a better answer. There is some external corrosion that is about the same whitish color and does look something like salt. I'll open it back up and see if the thermostat "paste" dissolves in water. The aluminum oxide won't, the salt will.

 

[Tom at oes]

kimcrwbr1,

I had never even heard of this product, but I see my local marine store has it. I'll give that a try. Thank-you.