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BF20: Cooling Problem

S

SV EmeraldSea

New member
We have a 2013 BF20 with a cooling problem. There is cooling water coming out the pee hole but as the engine warms up, gets hot, the amount of water streaming out either is the same or reduces to an near trickle. As I rev up the engine the amount of water being emitted does not increase as it did before. And then as the engine gets hotter it will sputter and stall. This happens within 10-15 mins of operation (we are in a tropical climate). Im assuming there is a temperature sensor that is commanding it to stop until its cool enough to restart. Im at a loss now as to what it is as I have done the following: replaced the impeller/housing, replaced the thermostat; replaced the pee pipe from the nipple to the shroud connector; ensured there is no debris at the base intake grills. If there is debris in the internal piping, how does one get into this to clean it out? Any tips or tricks are welcome.
Thanks
Steve
 
Flush engine in a tank with saltaway, Have you run a compression test on her ? Was the water tube leading from pump to powerhead inspected? Was waterpump housing sealed to l/u? What was the condition of old impeller ? Any pieces missing? Could be lodged up somewhere in block or heads.
 
Saltaway? We are presently and temporarily in Tahiti and while I will look for such a product, Im not hopeful. I have not done a compression test. Yes, the water tube to power head was inspected, blown thru with LP air. What is I/u? The old impellor condition was good, all vanes intact.
Im going to try and push a small bflex rod down the water pipe from the outlet side. If no affect I will then take off the lower motor unit again and reinspect for anomalies.
 
How can I find a schematic of the inside of the cooling system? Id like to know the what is located in the cooling system between the pee outlet and the impellor/housing? Internal pipe diamters, restrictions, etc. Where some debris may have become lodged.
Steve
 
What did the inside of the thermostat housing look like? Clean? Corroded? If you see where the salt water has been attacking the aluminum and causing the white, powdery looking oxide to form, you could use some good old white vinegar to clean things up.

If corrosion doesn't look all that bad you may want to take the l/u (lower unit) back off and double check your pump installation.

The most common mistakes made are:

Installing the impeller backward

Using old drive key and having it cock vertically and not efficiently drive the impeller. Always use a new drive key.

Not lining up the drum that the impeller sits in with the water intake slot. This starves the pump of water and leads to almost immediate pump damage.

Not positioning drum in pump housing properly and making sure the lock tabs are keeping it from working around in the housing. This too causes fast pump deterioration.

With the lower unit off, remove tstat and test that it fully opens in a pan of water. It should start opening around 150f and be fully open around 170f.

With the tstat removed and lower unit off, you can now "backflush" the system by inserting a hose nozzle in a passage opening in the housing and use a rag or sponge to seal the other opening. Give it all the water pressure you have, it won't hurt anything. You can do the same with compressed air, full pressure. Using water and air at the same time is most effective but there's a special tool for that. Alternating water and air, sealing each open passage as you do, should loosen and eject any debris out of the bottom of the water tube or tube passage.

Take the pee tube off and remove the nipple for it from the engine block. Give that passage the same backflush treatment.

I'll look in my shop manual and see if I can find any more tips for you.

Good luck.
 
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JGMO. Thanks for your support. Its seems I have fixed one problem but it remains with another.Checked all the above. I removed the l/u and checked the impeller (good, in tact), blew with LP water via the pee hole thru to the thermostat and l/u and lower intake - small pieces of weed came out and the air flow thereafter seems normal/good. For the cooling system it all seems OK. I reassembled it all and took it for a test ride: proper flow of water from the pee hole again - increased flow as speed increases. But then….


After about 10mins of driving low to medium revs, the Honda started to cough and it stalled. I wait 5 mins and it will restart again and run fine, only to cough and stall 3-5 minutes later. The exhaust cooling water is warm to the touch, not hot. I squeezed the fuel ‘bubble’ to ensure fuel flow. I unscrewed the lower carb bolt to check for fuel in the carb - OK. Note that earlier this month I have: changed the fuel filter, changed the fuel pump, changed the plugs.


Any ideas what can be the issue here?


Thanks, Steve
 
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