Tohatsu MFS30B Alarm

GM1Wolf

Recruit
Joined
May 2, 2016
Messages
2
I ran the boat for just over 6 hours brought it home and commenced the fresh water flush. Everything was going well until 20 seconds into the flush. The low oil pressure/water over temp alarm went off, so I shut her down and started troubleshooting. Verified oil level and double checked water inlets were not clogged. Hooked up motor flush and tested again; same results again 20 seconds into flushing alarm goes off. Decided to start troubleshoot some more and ended up changing the oil and filter. Cranked her back up and no alarm, YAY!!! :D
Fast forward approximately 24 hours, same scenario. Went out for 6 hours (no problems at all), brought boat home and commenced fresh water flush. Guess what happened... you got it alarm went off again.:mad-new: This time I changed out all the soft materials in the water pump i.e. impeller, gaskets. I cranked her back up and still got the alarm. The oil level is good and I am getting good water discharge. I will change the oil and filter again and see if that makes the alarm go away again. If anyone has any other ideas on what might be causing the alarm to continue to go off I would be glad to hear them.
 

pvanv

Admiral
Joined
Apr 20, 2008
Messages
6,509
What method are you using to flush? Did you block the sub water strainer with tape? If using the flushing attachment, did you also block the side water inlets? Is the hose running as much water as possible? Are you getting a continuous horn as well as warning LED? If you shut down and re-start, does the alarm come back on immediately?
 

GM1Wolf

Recruit
Joined
May 2, 2016
Messages
2
Paul, thanks for the reply. I am submerging lower unit approximately 24" - 26" into a water trough to flush. I am getting a continuous horn and LED at 20 seconds after start up. If I shut down and re-start the alarm does not come back on until 20 seconds after starting. I have an oil pressure switch, water temperature sensor, and thermostat on order. I will replace those and see what happens after that.
 

Sea Rider

Supreme Mariner
Joined
Sep 20, 2008
Messages
12,345
Post a pic of flushing method, you're undergoing a costly troubleshooting method. Does the trough has fresh water passing in and out while flushing ?

Happy Boating
 

pvanv

Admiral
Joined
Apr 20, 2008
Messages
6,509
Your dealer may have a diagnostic kit. If so, they can diagnose the temp, etc., very fast and easy.
 
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