1987 225 Johnson warning horn acting up

[Blake0912]

I have a 1987 225 johnson that just started having warning horn issues. When im running over 4k RPM the horn will start to sound like its going to go off then stop, basically when the boat bounces the horn will make a sound but not full blast kinda like a screech, but if I back off the throttle it will stop. I checked the temp of the engine with a temp gun and its not over heating. So my thoughts are it has a fuel restriction, but why wont the horn blow full blast if there is a fuel restriction? I can still get 5500 RPM out of the motor. It almost seems like there is a short or something causing the horn to malfunction.
I did ground my brown temp sensor wire to the block with my key in the "on" posistion and the horn sounded off loud and clear.
Also I have recently replaced the fuel pump, fuel filter, fuel water seperator , new fuel lines, new primer bulb. I have not checked the anti-siphon valve on the tank yet or checked to make sure the tank vent line is not clogged. My plan was to hook the motor up to a 6 gal aux tank and run it to see if the problem will go away, meaning I have an issue with my fuel tank.

Anybody have any ideas what else could be causing this problem?

thank you

 

[sutor623]

Re: 1987 225 Johnson warning horn acting up

It almost seems like there is a short or something causing the horn to malfunction.
I
thank you

Nailed it!! Trace the wire from the switch in the cylinder head back to the control box. If you dont find the short there, open up the controls and check in there. You didnt say anything about waterpump....... I would change that also, just cuz.....

 

[Blake0912]

Re: 1987 225 Johnson warning horn acting up

I looked at the wires next to the warning horn insides the controls and did not see a short ill try chasing the wires to the motor next.
i changed the water pump and thermostats about 6 months ago, getting 20-25PSI idling with t stats closed and 15ish PSI running with t stats open so im very comfident its not over heating and both banks are running about the same temp.

 

[sutor623]

Re: 1987 225 Johnson warning horn acting up

Cool man, glad to hear that. If you cant find a short in the wire, you more than likely have a short in the switch. Those switches are a bit pricey, plus you have to remove the head/heads to swap em out, so you would also need a head gasket. Its going to be fun figuring out which one is bad. Some would clip or disconnect the wire to silence the alarm, I am paranoid so Id never do that. If you have to figure out which switch is acting up, you could clip one wire on one switch and take the boat out. If it still makes the noise, its the other one thats bad. Reconnect the wire that was clipped or disconnected, and then replace the other switch.

Good luck bud! I hope you find a short elsewhere so you dont have to replace a temp switch......

 

[sutor623]

Re: 1987 225 Johnson warning horn acting up

Evinrude Cylinder & Crankcase Parts for 1987 225hp E225CLCUB Outboard Motor

Check out part #28.

 

[boobie]

Re: 1987 225 Johnson warning horn acting up

You don't have to take the cyl heads off to replace a temp switch if you have to. They just unscrew out of the cyl head.

 

[Blake0912]

Re: 1987 225 Johnson warning horn acting up

Is there also a fuel flow restriction sensor? I was thinking it may not be the temp sensor since the horn wont try to sound unless im over 4k RPM and when I back of throttle say from 0-3900 RPM it wont come on at all.

And how would I test my temp switches, ground each banks tan wire to the block and see if it will sound off? I Know my port side sensor is working, but have not tried the other.

 

[boobie]

Re: 1987 225 Johnson warning horn acting up

The fuel restrictor sensor is near the vro on the port side of the block. Find the tan wire going to it and disconnect it. If the horn shuts up, then check for a fuel restriction in the fuel system.

 

[sutor623]

Re: 1987 225 Johnson warning horn acting up

Hey boobie are these fuel restrictor sensors only in the VRO models?

 

[boobie]

Re: 1987 225 Johnson warning horn acting up

Only on the V-6 's

 

[Greg_E]

Re: 1987 225 Johnson warning horn acting up

One more vote for a fuel restriction. When you replaced all the lines filters etc. you used all 3/8' fittings an lines, correct?

 

[Blake0912]

Re: 1987 225 Johnson warning horn acting up

Yes all fitting are 3/8th, what would the signs of a fuel restriction be? My primer bulb is not being sucked dry and I can get full WOT rpms out of the motor.

 

[Greg_E]

Re: 1987 225 Johnson warning horn acting up

At high rpms the effort required to pull the necessary amount of fuel from the tank is greater than what the fuel restriction sensor needs to close and cause an alarm. I've never taken one apart, but it looks like it is a simple vacuum switch. A blockage would collapse the ball. A restricted line might not.
Have you tried what Boobie has suggested?

The fuel restrictor sensor is near the vro on the port side of the block. Find the tan wire going to it and disconnect it. If the horn shuts up, then check for a fuel restriction in the fuel system.

If you're sure all the lines fittings from the tank are good check that the vent for the tank is in good working order. Sometimes the screens in them can get clogged.
If you connect an auxillary tank to the engine and you don't have the problem the problem is in the boats fuel system. If not maybe the sensor is bad.

 

[Blake0912]

Re: 1987 225 Johnson warning horn acting up

First ill try the aux tank followed by boobies suggestion. My tank vent has been acting up last time at the gas pump it was not venting fast enough and I got a volcano of fuel spilled all over the deck, I disconected my vent line from the vent on the boat and put it out in the open and it pumped just fine. So i blew compressed air into the vent and it seem to clear it out. I think i had some wood chips in the vent from the boat rubbing against the dock. But I will attempt to pull the vent off the side of the boat and see if there is some kinda of screen blockage.