Strange Noise when trying to start boat...

[snipe0209]

The last two times I have been out I have had a very bizarre noise come from the gearbox when I went to start the motor. Both times I have had no problem getting the boat started at the ramp or anything, but then I will go to start the boat at some point on the trip and a "horn" will sound from the gearbox. I have no idea what this is, but I assume that it means don't start the boat right now. So I will fish a little while longer and try again. Eventually I will turn the key and it does not make the sound so I start the motor and go on. It runs fine.

The motor is an 80's model Johnson 110.
Anybody have a clue what this may mean? What is causing it?

 

[wrechin2]

The alarm will sound for several reasons.

OVERHEAT: Continuous solid tone.
NO OIL: Continuous short pulses
LOW OIL: short pulse every 40 seconds
FUEL RESTRICTION: Continuous solid tone near WOT

Hope this helps!

 

[snipe0209]

Wrenchin,

Thanks for the info. Please clarify what do you mean "near WOT?" I suspect that this fuel restriction is more likely than anything as there has been some rust that was in the fuel tank. I have installed an inline fuel filter which can be easily changed to address this problem and I am hoping that it will all flush out soon.

The first time that I encountered this problem everything was running great and then it just died. I looked and noticed that the primer bulb on the fuel line was suck in. I clean the filter that is just inside the tank at the fuel line connection and that helped but the filter seemed so small and was pretty difficult to get to so that is when i decided to go to an inline that you can see very easily if it is clogged and replace it very easily as well.

Is there any way to confirm whether it is an overheat alarm or a fuel restriction alarm?

Thanks so much.

 

[Auburnwes]

WOT = wide open throttle

 

[Auburnwes]

Auburnwes - 3/20/2010 9:18 PM

WOT = wide open throttle

Hope you figure out whats wrong!!

 

[wrechin2]

If the bulb is sucked together, then it is more than likely a restriction alarm.

WOT= WIDE OPEN THROTTLE. This is where the fuel pump would be creating the most vacuum. If the alarm is going off and the bulb is sucked together, then it is probably it. BUT Not all engines are equipped with the fuel restriction sensor. VAST majority of them are.

 

[wrechin2]

Dang you WES!!!LOL!!! you posted the same time!!!!

 

[snipe0209]

Well knowing now that WOT= Wide Open Throttle I would think it less likely that is that cause of the problem since the two times I have heard this alarm it the motor has not even been started.

How could I determine if it is an overheat alarm? Would a bad impeller cause this? I have noticed that the motor doesn't pee very strong. It pees but it seems like it may be constricted.

 

[mmarcum6]

when was the last time you changed the impeller on the water pump? If it has been more than 3 years it definatly needs replaced and the housing also needs checked for wear. This may not be the problem, bit it may prevent one down the road. Good luck!

 

[wrechin2]

It can be determined if it overheat. It may be that it was almost to the point of overheat and when you turned it off and the block drains, then it actually had overheated. I had a 150 60* that was hard to start after a long run and short fishing session. Replaced the impeller and the issue went away. It apparently was running hot but not hot enough to sound the alarm or to trigger SLOW. Some power packs have a system that will pull the RPM's back to 2500 if overheated, low oil, fuel restiction, and no oil to help prevent damage. I believer the starter was overheating and dragging from the additional heat.

I agree with mmarcum6 on replacing the impeller. What is strange is Mercury wants them replaced yearly and OMC doesn't really have a interval for replacing them. I have a few factory manuals and I have yet to find a service interval on the water pump. I have always heard 3 years on OMC. Yet they are made out of the same material. Go figure.