Honda BF9.9 cooling water flow problem

[tpbeebejr]

Below are the numbers for my 9.9 HP Honda outboard:

Product Identification Number: BABJ-1,608,742
Engine Serial Number: BEABJ-1,035,329
Model Number: BF9.9D/10D (SHA)
Model Year: 2007 0r 2008

After returning from a nice day on the water I was using the earmuffs to rinse out the salt water. I noticed that the water flow from the pee hole first began to only spit intermittently, and then it stopped. I turned off the motor immediately.

* I removed and cleaned the inlet screens (which were completely clean already).
* I removed and cleaned the pee tube and its chassis feedthrough, which were both also clean already.
* I removed the cover for the thermostat, removed the thermostat, and replaced the thermostat cover.

Upon starting up the engine with fresh water flowing through the earmuffs, the pee hole immediately started flowing again. Am I correct to conclude that I should replace the thermostat? If so, can you please paste in the parts diagram and part number? If this is not the correct diagnosis, please send me some ideas for things to check. I do not yet own the Honda garden hose adapter kit, but I plan to buy one. Is the flush kit better than, just as good as, or not as good as the ear muffs when it comes to thoroughly rinsing out the salt?

Thanks,
Tom

 

[Sea Rider]

Thermo has nothing to do with pee hole, you need to have engine on while flushing so thermo opens and cleans head water passages. Was thermo in good clean state, that's not rusted, excesively salty ? If so put a new one. Check also your water impeller at lower unit, probably needs replacing to pump better.

Happy Boarting

 

[tpbeebejr]

Thanks, Sea Rider. Perhaps I wasn't clear. The engine WAS running when all of the above happened. That is, I was running the engine with fresh water flowing through the earmuffs when water flow from the pee hole first began to only spit intermittently, and then it stopped entirely. I then turned off the motor immediately.

In order to better understand this, where can I find a "plumbing diagram" of the cooling water system on my Honda model number: BF9.9D/10D (SHA)?

It sounds like you are saying that there are two different cooling water circuits: 1.) one that flows in through the earmuffs and follows a loop that does not include some parts of the head's water passages, and 2.) an additional cooling loop that opens up when the thermostat opens, and passes through additional water passages in the head. If so, then removing the thermostat (for an experiment for rinsing purposes only) should allow me to rinse ALL of the cooling water passages. Is this correct?

Thanks for your help.

 

[Sea Rider]

Yes, if you remove thermo will have unrestricted water passing throughout all water passages, one issue to consider, unless you have an oustanding water pressure at home for neat flushing purposes keep in mind that most muffs loses to much water pressure through rubber ears that could lead to a intermitent peeing. Have you checked your impeller condition ? You could blow compressed air or W40 upward peee hole, if there's any small clog there should free it nicely

Happy Boating

 

[tpbeebejr]

Thanks, Sea Rider. I'll try your suggestions.
Tom

 

[tpbeebejr]

Hey Sea Rider, or anyone else out there: If you are given the choice, would you rinse out salt water using a.) running the motor with ear muffs with average house water pressure; b.) running the motor with the garden hose rinse adapter located just above the thermostat housing, or; c.) running the motor in a bucket of fresh water?
Thanks,
Tom

 

[Sea Rider]

Tom,

Each method has its own pros and cons :

Muffs, loses excesive water pressure through rubber ear sides, there's a solution to it, will need a excellent house water pressure to rinse properly..

Adapter, will probably need to seal lower water intakes so as not to lose water pressure there, downissue, on the long run if too much screwing/unscrewing cycles are perforrmed, will end damaging engine's threaded water intake port if happens to be a screw type.

Barrel, will need a engine stand to hold the engine vertically, after flushing will need to dispose oily, mess gallons of water properly.

Personally much preffer first two, muffs or engine adapter with engine on so thermo opens up and rinses all internal water passages fully. My patio doesn't have an issue with both methods. But due to use my engine all year round definitely prefer muffs all the way.

Happy Boating

 

[tpbeebejr]

Thanks, Sea Rider, for the nice summary of the pros and cons of each method. Yes, it is a screw-in type flush adapter. When my adapter arrives from Honda Parts in a few days, I intend to modify it so that it stays on the engine permanently. Depending how it looks on the other end (garden hose end), I will extend it through a hole that I will drill in the hood, perhaps with an in-line quick-connect so that the hood can be removed completely. So for just rinsing after salt-water use, I can just hook up a hose, turn it on full blast, and run the engine without needing to even take off the hood. If I need to take off the hood, I can just disconnect the quick-connect (leaving the screw-in flush adapter in place essentially forever. If it works well, I'll post some photos.
Thanks,
Tom

 

[Sea Rider]

Tom,

Does Honda gives any indication on Owner's Manual regarding that you need to tape lower water screens so as to lose best water pressure when using the adapter ? On some engine brands must do so. Check. If going for muffs, could make this simple adaptation, muffs will hold much better onto lower leg when flushing than when factory delivered. You can tight tie a bungee rope permanently instead of the strap, will assure much better overall water intake than before.







Happy Boating

 

[tpbeebejr]

The Owners Manual doesn't say anything about covering the lower intakes when using the upper flush adapter kit.

I see what you mean about improving the seal with the earmuffs. My earmuffs leak a lot when I use them, so I will definitely try to make the seal better. I also need to find bigger muffs, since mine don't completely cover the rectangle intakes. I'll try the strapping technique - pretty smart idea!
Thanks,
Tom

 

[tpbeebejr]

My flush adapter arrived and I have used it several times. It seems to be a very good way to rinse with fresh water since there is no leaking, as with earmuffs. It is not possible to keep the as-provided flush adapter screwed in and fit the motor's hood on. However, it is close. I have found that if I pull the rubber hose gasket out of the female brass nut (the one that screws onto the hose's male end), I can then slide the female brass nut back onto the stem of the flush adapter. The rubber gasket can then be stored on the stem of the flush adapter. Now the motor's hood will fit back on without having to remove the flush adapter. This is how I now leave things. I only have to remove the hood and hook up the hose. It isn't too big of a deal to flush with fresh water now.
Thanks