Update: horn works - restricted fuel vent seems to be the problem, 89 Evinrude 150

[JonTX]

We put this motor back together - all new fuel lines, fuel filter, temp switches and t-stats have been tested and work. In the driveway with muffs on the motor, after 5 minutes the horn alarms - solid tone. removed the wires from vacuum switch that is monitoring fuel restriction and horn stayed on. That switch has been tested with vacuum pump and it switches at 7" Hg. Next unplugged the tan wire from port side temp switch. Horn stayed on. Next unplugged tan wire from starboard temp switch - horn still on. Finally unplugged white wire from starboard switch and horn quit. I'm wondering now if the problem is the horn itself.

How can I test this horn and are there any other suggestions where to look next for the cause of this alarm. The motor sure does not feel hot. Thanks,...Jon

 

[ezeke]

Re: How to test alarm horn? 89 Evinrude 150 hp

Re: How to test alarm horn? 89 Evinrude 150 hp

I think the starboard switch is probably bad; The black and white wire is the control for QuikStart. It should not set off any alarm.

The way you test the horn is at the control by disconnecting the tan wire there. If the horn keeps sounding, the horn is bad. You have effectively already shown that the horn is good by getting it to shut off.

 

[JonTX]

Re: Update: horn works -restricted fuel vent seems to be the problem, 89 Evinrude 150

Re: Update: horn works -restricted fuel vent seems to be the problem, 89 Evinrude 150

ezeke, thanks for the information. After reading your reply, i searched around to find out what QuickStart was and how it works. The problem we had in the drive way test was plugging in the wrong wires. The wires coming from the motor are discolored to the point you have to look really close to see which one is which. So, with the white and black wire from the switch incorrectly plugged into the tan wire going to the horn, as soon as the motor warmed up a little bit and was trying to tell QuickStart to dis-engage, that signal instead was sounding the horn. Getting the wires sorted out and plugged in where they belong solved that problem.

On to the lake test: Everything ran fine until WOT and shortly after that here comes the solid horn again. My buddy was trying to pump the fuel bulb to see if that helped and the bulb sucked completely flat and stayed that way. This is all new fuel stuff, completely back to the tank and the pick up tube is clear so we were pretty sure the problem was not in the fuel line. Unscrewed the fill cap to let it vent and made another couple of runs at WOT with no alarm. Pretty sure now that the vent is restricted some sort of way, kinked line or something. He had pulled the vent line off the tank earlier and was able to blow through it from both ends, so the only thing we can think of is it must be getting kinked somehow when it's installed on the tank. I can't think of anything else it could be but if anyone has any ideas, please let me know.

Also, we cant find any anti-siphon valve in this system. The pick up tube has a screen on the bottom, and the top of the tube goes into an aluminum block with a hose barb at the outlet for the fuel line to connect. There is nothing in that area - open passage all the way. Any other likely areas for an anti-siphon valve to be located?

Thanks to everyone who has helped so far in figuring out this problem.

 

[Theoutdoorsman]

Re: Update: horn works - restricted fuel vent seems to be the problem, 89 Evinrude 15

It is possible you have some crud in the fuel cell. I've seen many a foil cover from oil bottles fall off. I always remove them completely before adding more 2 cycle oil to the fuel. It might be sucking up debris and clogging the screen on the pick-up tube. Possibly one of these foil covers from a rogue oil bottle...... ....... Also, if you have a kinked line, the restriction is likely to be between the bulb and pick-up tube. If possible, try cleaning the fuel cell.

 

[ezeke]

Re: Update: horn works - restricted fuel vent seems to be the problem, 89 Evinrude 15

If I understand you, when you opened the fuel cap, the engine ran normally.

If you have a vent that goes through the hull, it may have a screen on the outside that can become clogged, especially if you are around salt water. You can pry the screen out with an awl or a sail needle and clean it, then shove it back into place.

Most of the anti-siphon valves are just a spring and ball bearing in the outlet barb at the top of the tank. Coast Guard regs require them if any part of the fuel system is below the top of the tank. If the entire system and the engine are all higher than the fuel tank as in many outboard installations, they are not required.