Honda BF200 temperature alarm during flush with mufs

[Lacabana]

Hi,

I just got a new boat with a used (130 hours) Honda BF200 outboard. I bought mufs so I can flush the engine on my driveway directly after returning home.

After some 3 minutes running the engine the audible alarm for overheating comes on. Water flows properly from tell tale and exhaust at the prop.
My Simrad MFD is reading a 60-65 degrees Celsius which seems fine. However I’m not sure if this readout is reliable and what sensor is being used for the NMEA data feed.
The display for the engine is not giving a temperature reading at all just -/-, other data such as rpm, trim, etc do work.

Maybe the limited water pressure here in the Caribbean is the issue?
Thanks in advance for some guidance.

 

[MattFL]

Does it overheat when in the water? How about if you put it in a bucket/barrel instead of using the muffs? It's definitely not cooling for some reason. Now would also be a great time to replace the impeller.

 

[Lacabana]

Does it overheat when in the water? How about if you put it in a bucket/barrel instead of using the muffs? It's definitely not cooling for some reason. Now would also be a great time to replace the impeller.

Thanks a lot for your reply! Next time I will give it a try using a bucket and I already ordered a new impeller kit. The engine is not overheating in the water.

Could the alarm be false? Since the engine temperature according to my MFD with NMEA data seems normal.

The other thing I noticed is that when connecting a hose to the flush adaptor no water comes out anywhere, whilst with the mufs it all works fine. So maybe somewhere the cooling system is clogged?

 

[harringtondav]

Check p. 75 of the attachment. It doesn't mention using muffs, only the flush hose connector. It also states to not flush through the connector with the engine running. Appears if you get flow out the prop exhaust you're getting the job done.

You garden hose flow may be too low. FYI, My previous 4.3L Mercruiser's pump would deliver over 13L/min when tested with the boat in the water, pumping seawater @1100 rpm. If your hose flow is less than the O/B pump's capacity you could be starving the pump.

https://cdn.powerequipment.honda.com/marine/pdf/manuals/31ZY2603.pdf

 

[Lacabana]

Check p. 75 of the attachment. It doesn't mention using muffs, only the flush hose connector. It also states to not flush through the connector with the engine running. Appears if you get flow out the prop exhaust you're getting the job done.

You garden hose flow may be too low. FYI, My previous 4.3L Mercruiser's pump would deliver over 13L/min when tested with the boat in the water, pumping seawater @1100 rpm. If your hose flow is less than the O/B pump's capacity you could be starving the pump.

https://cdn.powerequipment.honda.com/marine/pdf/manuals/31ZY2603.pdf

Thanks! Problem is that I don’t get any water through the system when using the flush connector. I didn’t start the engine when using the flush connector, only when using the mufs engine is started.
Read somewhere that there is a pressure valve that needs to open up when using the flush connector, I’m afraid the water pressure here on Bonaire is just too low for it to open up.
If that’s the case maybe need to go for the bucket option, which doesn’t have my preference.

 

[harringtondav]

My current VP 4.3 has two flush connectors. One on the transom, the other next to the engine. Same hose I reckon with a T to the water intake.
I mention this because the illustrations in the enclosure and in a parts page I saw seemed to show two different connectors on your motor. If so, uncap both and see if water flows through. If you have a clog, this may open it.
Also maybe trace the flush hose to the main cooling system connection. Disconnect and see if water flows through the hose.

...low hose water pressure and that valve sounds likely. Find a large bucket, drop the L/U in, fill it and keep it as full as possible with the hose running. A flush is a flush. ....doesn't have to be pretty.

 

[MattFL]

I would think water should be coming out somewhere if you're connected to the flush connector. Maybe something is clogged. Get a piece of thick weed whacker line and run it up inside the flush connector, see if you can break anything loose or determine if there's gunk blocking it up somewhere.