My Merc is a bit sick

[SeaHunt]

2003 Model 60 hp EFI 4 stroke.
After it warms up the alarm sounds and then it will only rev to 3K.

I remember reading somewhere, and I thought it was on this site but I can't locate it with a search, that if something happens it will limit the revs and still run good enough to let you limp home.

Anyway that is what happened to me at the weekend.
I thought it might have something to do with over-heating, but the motor didn't seem that hot when I pulled the cowl off and there is still water coming from the tel tale although it seems to be pissin like an old man when it used to go pretty hard.

ANyone got any ideas

[outsiderskip]

it could be running on safety mode
if it has a computer

pete

[foxx510]

Sounds like it has simply overheated.

[Spaniard_King]

Sounds like you need a water pump service.. get them to check the thermostat too

[Jabba_]

You could of picked up a bait bag, which if raps around the leg it will block you water intakes.... When the motor drops it's rev's going into save mode, the usual thing that happens next is the boat operator will stop the boat to inspect the motor and tell tail, at wich point the bag come off the leg and drifts under the boat out off sight..

Wouldn't hurt to change you water pump also.....

[seajay535]

Mine was doing that pulled the leg off impellor ok.
Ended up taking it in and found rubber grommet where water pipe connects to powerhead had perished and was restricting water enough to put the engine into limp mode. Still had water out of telltale just not enough to cool properly

[David H]

You mention that the engine does not seem very hot, I had an outboard that was exhibiting the same symptom, ended up being a faulty temperature sensor.

However if the water flow out of your tell tale is low, the impeller is a good place to start.

[trueblue]

I would be checking out the cooling water side first... pump, impellor and housing inspection, and the thermostat/s

I have also had an engine go into safety mode when I had a corroded battery cable - it would go into safety mode if i tried to trim the motor under load. new battery cable and fixed!

cheers

Mick

[Noelm]

OK, we have been through all the "could be's" but we need to find out the positives, so does it still do it?? when it sounds the alarm, have you checked the Motor temp (by hand) straight away?? does it do it every time you use it?? do you have a genuine Manual so it will explain how to test the sensor and alarm? without any of those steps, we are only guessing at best, we are not even sure if it is over heating yet!

[Noelm]

OH and by the way, a Water pump is probably long over due and can't hurt.

[Donny Boy]

Sorry to hear that Bev...............

[SeaHunt]

Thanks all, (well nearly all) , I am inclined to think it is the thermostat or impeller slipping, causing overheating and reduced tel tale.
I am going to pull the bottom off it myself because I am keen to learn how to change the impeller etc. knowledge that might come in handy someday.
It is due for a service and I will put it in after that and tell them to leave the impeller if I change it myself.

[SeaHunt]

OH and by the way, a Water pump is probably long over due and can't hurt.

What exactly are you trying to say Noel m?

The motor has only 250 hours on it, this is the forth impeller it has had in it.
I was getting them changed every service and they would come out looking like brand new.
Last service was the first time I said if the old one looks fine leave it in, a mistake maybe but I wont know until I get a look at the old one, I think it is fair to expect 50 hours out of an impeller, especially if you havn't sucked up any sand into the motor.

[Noelm]

no offense intended, I was reading it as being oldish and did not see that it had been replaced ,the Motor is 5 years old, and no mention of replacement, only trying to help here, if you don't like any questioning, then so be it, get someone else to help out for free, no skin off my nose.

[FNQCairns]

Modern outboards are like computers, one day it decides not to work....mmmm, now will it be hardware or software or solid state...this time?? pull the side off poke around looking to be thunderstruck by lucky coincidence and find manna from heaven....an unplugged plug if not it's now time to sit down, have a coffee and wait for the experts shop to open to make a phone call, juggle the budget to fit a solid gold sensor or planinum plated solid state gizmo + labour into it this month.

One day we all will be forced to have a good and close albeit one way relationship with a marine dealer...

Seriously I hope it's something small, it might be, but with throttle position sensors, flow sensors, injectors temperature sensors - near everything any efi car has these days in one way or another......seek medical advice for anything over and above what a lone single blade screwdriver can poke at.

cheers fnq