An alarm went off

204 Escape

Ensign
Joined
Nov 17, 2007
Messages
909
We went to the lake yesterday, the first time out for the year. We made a run around the lake, and then went to a couple of coves for fishng.

Afterwards, we went to the marina to eat, and then went out for some tubing with the boyz.

While pulling the boyz on the tube, a alarm went off intermittedly.

I noticed that the temp. guage went up to between 175, and 200. It wouldn't stay up at the 200 degree mark, it would drop back down to 175. It changed back and forth.

I loaded it up and came home.

On the opposite side of the prop, on the lower unit, there is a hole, about 1/8" in diameter. It was plugged. I cleaned it out with a toothpick.

Could this have been the problem, or is it something else ?? :confused:

This is a 2006 5.0 Mercruiser carburated unit. 220 h.p.

(When I loaded the boat up, it only has 23.4 hours on it).
 

hydrick

Seaman
Joined
Jun 19, 2005
Messages
70
Re: An alarm went off

yes.

note too, that if the ignition is left on while loading the kids(engine off but swith on) it'll buzz too.
i'm sure you know that.
 

redone4x4

Lieutenant Commander
Joined
Feb 28, 2009
Messages
1,548
Re: An alarm went off

200 is too hot.....it should be down around 150-180 at the highest. I would feel better down around 150.
 

redone4x4

Lieutenant Commander
Joined
Feb 28, 2009
Messages
1,548
Re: An alarm went off

oops double post, sorry.
 
Last edited:

204 Escape

Ensign
Joined
Nov 17, 2007
Messages
909
Re: An alarm went off

Is it possible be a impeller ??

I'm not a mechanic, so this may be a poor question. :confused:
 

Jeep Man

Commander
Joined
Oct 17, 2008
Messages
2,803
Re: An alarm went off

I'm not familiar with i/o. You may get more answers if you re-post in the engine section for Mercruiser.
 

scoutabout

Lieutenant Commander
Joined
Oct 14, 2006
Messages
1,568
Re: An alarm went off

Yes, you will probably get more responses in the Mercruiser section...

That hole, while not as big as you describe, on my previous Merc Alpha unit was the inlet for the speedometer pressure sensor. Did you notice if your speedo was working during your ride?

The main cooling water intakes are the vents along either side of the lower unit, just above the gear housing.

Nonetheless, it is sounding more like an overheat situation all the time which means your impeller is not above suspicion. If you do not feel comfortable disassembling the the unit to inspect the impeller, have a competent mech check it out for you. Other things to look for are collapsed cooling water hoses in the engine compartment. Good luck!
 

gstanton

Chief Petty Officer
Joined
Jul 3, 2003
Messages
451
Re: An alarm went off

Might also want to check the oil level.

Just to be sure.
 

Ned L

Commander
Joined
Sep 17, 2008
Messages
2,266
Re: An alarm went off

If you have a 'complete' alarm system (for both high temp & low oil pressure), then the alarm is sounding with the key (ignition) on and engine not running because there is no oil pressure. In this situation no harm is being done. If the alarm is sounding with the engine running then something needs to be addressed. It sounds like it might be the high temp that you are looking into. The low oil pressure part of the alarm system is probably set for around 10psi oil pressure, if you alarm goes off again with the engine running check the oil pressure gauge to see if the oil pressure is low.
 
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