Honda BF90A alarms

"2001 BF90A with 1136 hours on

"2001 BF90A with 1136 hours on it. Replaced the impeller and Tstat ~15 hours ago after running at 4500rpm and the alarm went off, then engine shut down. Today ran to Stellwagen Bank after Bluefin tuna. When I arrived, I slowed to idle. After 5 minutes I couldn't rev over 1100 rpm in gear or out without alarm sounding and running rough. Oil light was on and water was streaming strongly out the indicator. Is the horn a heat or oil indicator? Plenty of oil in the crankcase- changed less than 100 hours ago."

"The horn works in conjunction

"The horn works in conjunction with both the oil and overheat. If the oil light is on, it is probably not the oil. You did not mention if the overheat light was on. The motor rpm will be reduced in both an oil alarm and an overheat alarm situation.

You can have an overheat even if it is peeing. If there is a blockage in the system. One common blockage is a thermostat stuck closed.

Since you probably do not have access to a temperture gun to check the actual temperature...

The easiest way to check the thermostat is to pull it and look at it. Many times there is debris keeping it from opening. There is a test in the manuals, where you put it in water and heat it up to see when it opens...or you can just run it without the thermostat for a test only. The motor does need a thermostat to run and idle properly, so do not continue to use it without a thermostat beyond the test."

"Thanks Mike. My mechanic inst

"Thanks Mike. My mechanic installed a used tstat. That's probably it, tho I could lay my hand on the head and it was less than 100*F."

Did I mention the exhaust resi

Did I mention the exhaust residue around the lower unit seam/exhaust port at the stern? I'm hoping that's not related!

"I don't know if that is r

"I don't know if that is related. That could come from many different things...the motor could be running too rich...maybe needing some carb work, passages cleaned, balancing, etc; the valves clearances may need adjusting; or the oil could be too high and it it buring some oil...just for starters..

There may be other issues going on with your motor. Your mechanic hopefully could perform a compression and leak down tests to check for cylinder or head issues."