Honda 75 alarm

pinboy122

Seaman
Joined
Apr 11, 2006
Messages
51
hi all, I’m having some trouble with my dads 2000 bf75
at full throttle after a few minutes an alarm goes off and it goes into limp mode. The alarm sound is constant and neither of the 2 lights on the control come on. If you put the shifter in neutral the alarm will go off and you can continue to full rpm for 30sec to a minute and it will do it again. If you just putt around or even half throttle it’s fine.
It has been reasonably maintained. It started this last year so I put a new thermostat in, no change. This spring I put a new water pump/impeller assembly in, no change.
I’m thinking maybe the temp or oil pressure sender but don’t want to just throw parts at it.
Any ideas???
Thanks,Al
 

pinboy122

Seaman
Joined
Apr 11, 2006
Messages
51
Yes, telltale stream is very strong and the water is warm but not hot. Also,the old impeller was all in 1 piece and in fairly good shape. I really don’t think it’s overheating...it’s kinda funny because once the alarm goes off and it goes into limp mode,I can just put in neutral and take off again with no alarms like nothing ever happened. Unless of course I try to run full throttle
 

pinboy122

Seaman
Joined
Apr 11, 2006
Messages
51
***update***
had some time to look it over today and this is what I found. I took the thermostat out and is was a little plugged up with some type of scale. I cleared it out and put it in hot water to test. It is stamped to open at 72c and did not even start until 78c, that’s like 161 to 173 Fahrenheit. I took a run after putting it back in and had the same alarm and limp mode on a full throttle run. Took the stat out and made a run and got no alarm but it doesn’t run as good without it. So I’m going to get a new thermostat and give it a try. I was hoping to find one that runs a little cooler but it seems that they only offer 1 temperature. Is there anything else I should be looking at or is that stat opening late enough to cause an issue?
Btw the lights on the control seem to be working fine now.
Thanks for your responses,Al
 

pinboy122

Seaman
Joined
Apr 11, 2006
Messages
51
Also, just found I can get a thermostat that opens at 140degrees,going to try that.

On a side note, I used to have excellent luck on this site but it seems not so much lately...I posted my same issues on a few other sites and had at least 10x the views and many excellent responses and advice. Kinda sad,this used to be my go to for advice and to help others
 
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