overheating horn??

[nosgsxr]

here is what is going on...its a 89 gt 150..i take the boat out and run it last week and she runs good...a buddy is wanting to buy the boat so i tell him to take it for a spin so he does...he didnt even get 100 yards and a steady horn went off when he hit full throttle...he backed it back some and the horn stopped...full throttle and horn go off..i drive and get the same thing but when i bring it back to half the horn started to fade out and a funny beep sound....i shot the heads with a temp gun and at idle and both sided were around 120/130...at fast idle both drop a little....with the boat under way the temp was only 100 ish on both sides...i checked it as soon as the horn went off and the temp on all holes were around 100....i tested the temp sensor by grounding it out while the key is on and got an alarm...tested the thermostates in a pan of water and they both opened up ..the alarm only goes off when you get full throttle and will stop when i get back to half throttle...

i put a new water pump in it and that didnt help but it did need one...is there any way to tell if i have a bad beeper or is there anything that would make this happing..would a stator or rec cause this problem mabey a coil pack i didnt see any broken wires.

thanks and i will be looking to see what yall think

 

[Dhadley]

Re: overheating horn??

What you describe is a fuel restriction warning.

 

[nosgsxr]

Re: overheating horn??

Well i kinda thought that also. Wouldbthat be in the carbs or some other place. I tried pumping the bulb while running but didnt help. It made no difference. Should i pull the carbs apart again

 

[nosgsxr]

Re: overheating horn??

ok after reading over some old post i need to check the fuel system vacuum switch ...where will this be located on the motor??

 

[emdsapmgr]

Re: overheating horn??

Bolted to the port side of the engine, behind the starter.

 

[clint]

The Overheating horn

The Overheating horn

Sounds like your engine is telling you its overheating. The horn will go off if the engine is too hot. Did you change your water pump before initial run? When was it last change?
Clint=)

 

[nosgsxr]

Re: overheating horn??

Ok the water pume was changed yeaterday and yes the old one was n bad shape. The horn didnt go off before but i was taking it easy on it.

I shot the heads with a temp gun while running and they didnt look to be hot. 110 and 105 on both sides when the horn went off

so is the fuel vacume swich servicable or replaceable. How can i tell if the unit is good or bad. Can i test it

 

[nosgsxr]

Re: overheating horn??

Also i cant find it on the parts fiche. Am i over looking it

 

[Dhadley]

Re: overheating horn??

An overheat is not so much related to throttle position. A fuel restriction will let the horn stop as soon as the throttle is reduced.

 

[nosgsxr]

Re: overheating horn??

So u think its a fuel problem?

 

[nosgsxr]

Re: overheating horn??

ok here is what i did tonite....i took the VACUUM SWITCH off and checked it ..what i did was rigged up a hose and created a vac i then hooked the ohm meter up and when pulled a vac it moved the meter so it looked liked it was working...i found a small hose that go to the manual choke was off and i thought i had it fixed so i head to the water at midnite to run her...well guess what still beeping....i pretty sure its a fuel problem but dont know where to start...

there is a metal fuel filter on the line coming in....i think its a auto fuel filter ...will this make a difference...maybe its not flowing enuff fuel or it could be that its used on a FI system and the outboard does not have the pressure to push/suck the fuel at higher rpm's....

i took the fuel line going into the motor off and pumped the bulb into a container and it flowed freely and the fuel looked great so i dont think its in the tank or the line to the motor

the top two carbs look as if they r sweeting on the out side of the throttle body not sure if that means anything but putting it out there..i ran the boat for a total of 10 min tonite and most of it was at 1/4 throttle

here are a few vids of the boat runing tonite ...there will not be any pics but got the sound of the horn and you can hear the rpm's of the motor. the last vid is of the temp as soon as i pulled it out of the water.

http://s240.photobucket.com/albums/ff290/nosgsxr/?action=view&current=IMG_0569-1.mp4

http://s240.photobucket.com/albums/ff290/nosgsxr/?action=view&current=IMG_0570.mp4

http://s240.photobucket.com/albums/ff290/nosgsxr/?action=view&current=IMG_0571.mp4

 

[emdsapmgr]

Re: overheating horn??

That vacuum switch will signal the alarm when it reaches around 7 inches of vacuum. At that point, you can start to lean out the engine at high speed. A twisted fuel hose is enough to cause a restriction that will set this warning off. Make sure you have 3/8" hose from the tank direct to the fuel pump. Check the anti-siphon valve for proper operation-they can stick partially open and cause a restriction. The best way to check this is to tee a vacuum gauge into the fuel hose and take it for a spin. You probably won't see much vacuum till you get the rpm's up significantly.

 

[nosgsxr]

Re: overheating horn??

ok thanks for the info...where is the anti siphon valve located?? do you think the fuel filter could be the problem i know it came from auto zone so its for a car...

 

[ezeke]

Re: overheating horn??

It would be preferable to use a full-sized water separating fuel filter designed for an outboard motor. Also avoid redundant filters in the fuel system.

The anti-siphon valve is located at the top of the tank in the outflow fitting. It is usually a spring-loaded steel ball and can be removed if the fuel system is all above the level of the tank.

 

[nosgsxr]

Re: overheating horn??

So it will run fine with the valve removed

 

[acabtp]

Re: overheating horn??

So it will run fine with the valve removed

It will run fine when you find and remove the fuel restriction. Could be that valve, could be the filter, could be a crimped line, swap some parts out.

 

[nosgsxr]

Re: overheating horn??

I have replaced all the fuel line with new 3/8 line. The filter is new but i still dont have any faith in it so im getting a new one today. Im going to check the valve today. Will regular fuel work fine. Just making sure its not sucking it closed

 

[nosgsxr]

Re: overheating horn??

ok i replaced the fuel filter with a new one from the boat shop...i cant get the anti siphen valve out of the top of the tank....its just spinning here is a pic of the valve

im headed to the lake to run it ...i hope this fixed the problem...no kinked lines ..i will let yall know in a little while

 

[nosgsxr]

Re: overheating horn??

i think i got it.....ran it for 45min tointe and no horn yay im so happy....i think it was the fuel filter....