Buzzer at first start-up of the year

[gregmsr]

Got the boat out after setting all winter (some days below zero this winter).
New fuel filter, fuel pump diaphragm, tested overheat buzzer, just a few maintenance items.
Dropped it in the tank, fired right up.......all is well, pumping water out the tell tale, sounds good!
Then, after about 5 min, the buzzer sounded....first time i've ever had it sound.
Shut it off, grabbed the heat gun and read 180 degrees on the head.
Hmmmm......
Got out the air hose, shot a few blasts up thru the tale tell, bubbles coming up out the tank.
Fired it back up, no buzzer after that... pumping water very well, all is good (I guess).

Now, i assume a critter had built a nest somewhere, some sort of blockage i guess.

Using the heat gun, these are the temps I read shooting the block, then the cylinder head at the level of the spark plug holes while running:
Block- 120-130
Head from top top bottom- 128, 140, 153, 157.

I found it interesting the temperature got warmer the further down you go.
Water falling down thru the block heated up as it fell down, I assume.

Any comments on these temperatures? (now to get off work long enough to put it in the water)
Anyway, some interesting stuff...to

 

[pnwboat]

Re: Buzzer at first start-up of the year

Couldn't imagine what the compressed air could have fixed. Very strange. Anyways, the real test will be out on the water.

The water flow through the water passage in the head is from top to bottom. I would assume as it passes over each cylinder, it gets heated up a bit more. It exits the engine at the very bottom and gets dumped into the exhaust tube cavity in the lower leg. I would guess that you have a 130? thermostat.

 

[MickLovin]

Re: Buzzer at first start-up of the year

The buzzer from my understanding goes off at 160degF, your highest reading is close but as pnw says the water test at WOT will tell you.

 

[jerryjerry05]

Re: Buzzer at first start-up of the year

Change the impeller anyway!!!

 

[gregmsr]

Re: Buzzer at first start-up of the year

Only if I can talk my wife into lifting the LU up again and holding it while I start a bolt.....
Seriously, it is pumping a good, strong, steady stream out the tell tale. The impeller was replaced exactly one year ago and only maybe has 4-5 hours on it in clean, lake water.
I just had the overheat sensor out for testing...maybe it was hypersensitive to the heat for a moment?

But we did have a brutal winter here in VA....something could have happened to it? (it is pumping strong though...)

 

[Jiggz]

Re: Buzzer at first start-up of the year

Well, if it ain't broke don't fix it. But at the first sign of another overheating, replace it.

 

[Nordin]

Re: Buzzer at first start-up of the year

For your information guys the lowest cylinder always gets warmest on an OB.
The explanation I have been told, it is because all exhaust from the other cylinders is passing beside the lowest cyl. at the exhaust camber and heating it up a bit more then the others.

gregmsr did you test it on muffs with a gardenhose?
If you did, it maybe a solution why the buzzer got off depending on that the waterimpeller sucks more water then the gardenhose can deliver and the muffs do not seal enough to the leg.

But as jerryjerry says check the impeller it is a cheap insurance.

 

[gregmsr]

Re: Buzzer at first start-up of the year

I always run it in a tank.
I plan to change the impeller, if I ever get a day off from work....