1999 yamaha salywater series 250-mind blowing issue

[captain217849]

ill make this as short as i can. i have twin 1999 yamaha 250. i replaced the starboard powerhead along with some other minor things. now after you run for about 30 min an alarm sounds, rpms cut to 2500 and 3 lights blinking on gauge. thought is was an oil problem, replaced all floats and main and small tank are full. oil system works fine, pumps oil as it should, alarm still sounds. then noticed the alarm would sound everytime engine was put in gear. replaced throttle position sensor and cables, alarm still sounds. replaced both actuator boxes, alarm still sounds. dual station set up by the way. replaced sensors in boxes for upstairs, alarm still sounds. Heres the kicker and nor myself nor my mechanic could believe this, when you TRIM THE ENGINE..it sets off the alarm every single time. we are baffled at what it could be, any ideas?

[muskrat1]

Faulty trim sensor? Might want to OHM it out.

[captain217849]

but why would the gauge light up like an oil problem?...all three arrows for no oil, low oil and even good oil all blink at the same time. oil system is fine

[99yam40]

Seems like I read that some motors had a low battery voltage alarm, and I believe it caused all lights to flash
By hitting trim it lowers voltage that Ecu or what ever sets of the alarm is seeing, probably bad connection/ corrosion.
Something to look into

[crosswind7]

similar problem

I had an almost broke power lead to controls last year and would do the same thing with alarms and trim I was at sea when this happened mine would only sound above idle or as soon as you hit the trim. I would check your battery connections and leads all the way to controls, good luck!

[captain217849]

yea reading more about it, it seems like a power problem, i also remembered that we were working on it one night and everytime we hit the engine trim and the alarm would go off, the dash and gauge lights would drastically dim. Maybe it is a connection problem somewhere?, but if it was would the alarm constantly go off? not just when the engine trim is hit or shifting?

[99yam40]

alarm would go off when ever it saw low voltage, all depends on where the bad connection was at and if motor charging systems are working properly

[jb123]

maybe try isolating the upper station/disconnect it to narrow down your prob

[99yam40]

I do not think the low voltage alarm comes from that area.
fairly sure it comes from motor

[captain217849]

all i know is that this alarm is going to be the death of me. when you run the boat, you can almost time it. when the boats cold it doesnt go off, its almost as if once the boat gets warmed up it starts. usually about 30-45 min after the boat is being ran, the alarm will trip. once it trips, it will go off all day. turns off when it wants, comes back on with no rhyme or reason. you could be running at 3500 rpms, or i could be slow *****ing doesnt matter. shift into forward or reverse, itll go off, go into to neutral it turns off. hit the engine trim, whether on the actual shifter or even on the engine, itll go off. but what has us stumped is why its throwing an oil alarm. why would the gauge have all 3 arrows blinking? makes no sense but im going sunday to check all connections. even the yamaha manual for this engine says the only time that you will get an alarm to sound with the 3 blinking lights on the gauge is either clogged oil filter (which it defintely isnt) or it says to chek connections which we have done but gonna try again