johnson 150 95 alarm at 5400 rpm

[phoenixgold2100]

I have a 1995 Johnson 150 and after using the boat for 5 minutes at 5400 rpm the alarm sounded.

It was a solid alarm for a few seconds then stopped then started again.

I know it's not overheating as I have two temp gauges hooked up and they never went past 150. they were at 110 when the alarm was going off.

I have added an inline filter and there is some stuff in my tank that I am trying to filter out.

Do you think it's a fuel restriction caused by the inline filter I added? the engine has one filter in the engine

I have just taken carbs off and cleaned them.

 

[Joe Reeves]

Re: johnson 150 95 alarm at 5400 rpm

Removing the inline filter temporarily would answer that question.... best to have a large water/fuel separator installed.

Another cause could be as follows:

(Fuel Anti Siphon Valve)
(J. Reeves)

Many of the later OMC V/6 engines incorporate a fuel restriction warning via a vacuum device attached to the powerhead. If the engine overheats, or if you have a fuel restriction, the warning is the same.... a steady constant beep.

NOTE... Only the V/6 & V/8 engines have the above "Fuel Restriction Warning". The warning horn will not sound on the other models.

The fact that a engine is not overheating, but the warning horn sounds off with a constant steady beep, and that the rpms drop drastically would indicate that the engine is starving for fuel due to a fuel restriction. Check the built in fuel tank where the rubber fuel line attaches to the tank fitting. That fitting is in all probability a "Anti Siphon" valve which is notorious for sticking in a semi closed position. It will be aluminum, about 2" long, and the insides of it will consist of a spring, a ball, and a ball seat. If this valve exists, remove it, knock out those inner components which will convert it to a straight through fitting, then re-install it. Hopefully that cures the problem.

The above procedure will cure a restriction problem with the anti siphon valve as stated. BUT, it may also allow fuel to drain backwards to the fuel tank when the engine is not running (siphoning backwards) due to the fact that the carburetors/fuel pump etc are higher than the fuel tank. This condition is not an absolute as the valves in the fuel primer bulb usually prevent this backwards siphoning problem. However.... if this does take place, the cure would be to install a new anti siphon valve.

NOTE: There has been cases when the output valve in the fuel primer bulb would come apart, and the inner portion of the valve would actually reverse itself and be drawn back into the primer bulb's output valve body. This in effect would create a shut off valve and result in a fuel restriction. If this is the case, you should be able to feel something laying in the bottom of the primer bulb when held horizontally.

 

[phoenixgold2100]

Re: johnson 150 95 alarm at 5400 rpm

I just installed a new primer bulb. It does not drop rpms. I have blown into the fuel line going to the tank and do not feel any obstructions.

One thing I forgot to add was I have disconnected the port side temp sensor and only have the white wire connected as this sensor was putting me in slow mode. Could this be it?

Another thing is I do not believe my quick start is working as it does not rev up when started cold.. seems to idle normally. Even if I push in the key it actually will drop rpms and want to stall out..

Not sure if that's related....

 

[metriccrescentwrench]

Re: johnson 150 95 alarm at 5400 rpm

With the engine cold check the continuity to ground from the sensor with the brown wire that you disconnected. It should be open, if not it's a bad sensor.

Pushing in the key has nothing to do with quick-start, it energizes the primer solenoid. Pushing it with the engine running will make the engine run rich and will drop the rpm's, and in fact doing this is the test to see if the primer solenoid is working.

 

[phoenixgold2100]

Re: johnson 150 95 alarm at 5400 rpm

Oh ok... I figured it was working because of the drop in rpm.

one question about the primer... Should I turn the key hold in the key for 8 seconds then keep holding it while starting the engine?

So how do I know if the quick start is working and how would I get it to work if it's not working?

When I start the engine cold I think it should go to 1500 rpm and slowly come back down? It stays around 1000 rpm

I have checked the star side temp sensor and it is open as I am not getting a constant alarm meaning it's grounded.

but with the port side tan wire being disconnected would it cause the quick start to not work?

The engine does start right up cold but I have to start it a couple times to keep it going when cold..

I prime it with the bulb but I have not been holding in the key for any period of time as I just read to hold it for 8 seconds last night if that's how I should be doing it of course.. thanks guys.