91 150 Evinrude alarm

[rotor21]

The situation is that I have a 23? quest with twin 91 150?s I purchased the boat three weeks ago. The problem is that I can match the engines at 3300 RPM and run all day but when I run over 3500 the starboard engine gets the steady alarm and retards to 2500 RPM I can shut it down and start it right back up and it will run at 3300 all day again I can run the engines up to 5500 RPM and take a hole shot with great power both but after a minute if I don?t bring the starboard engine back to 3300 RPM I will get the alarm the VOR is disconnected wires and all and the alarm is steady not a beep I have changed the thermostats water pumps and used a thermal gun to check the temp of the heads and they all run around 150 degrees I have ran an auxiliary fuel tank right to the starboard engine and still have gotten the problem. Please any help or suggestions are greatly appreciated.

 

[rotor21]

Re: 91 150 Evinrude alarm

anyone?? or maybe someone can point me in the direction of some advice?

 

[ezeke]

Re: 91 150 Evinrude alarm

You should also get a constant alarm on those engines if you have a fuel obstruction. The alarm is triggered by a vacuum switch located on the fuel line near the fuel pump.

Here's a similar thread on XL/GL 150 models with S.L.O.W. engaging; emdsapmgr is an excellent technician: http://forums.iboats.com/showthread.php?t=403371&highlight=Mode

 

[emdsapmgr]

Re: 91 150 Evinrude alarm

Follow ezeke's advice first. Since you are getting a horn, you also could have a defective temp switch in one of the heads, triggering a false alarm at 150 degrees. (usually the head switch has to sense 200/212 to trigger a hot horn.) You could try disconnecting them one at a time. There is a knife connector about 3" from the switch in head hiding under a rubber casing.

 

[rotor21]

Re: 91 150 Evinrude alarm

thank you for the great direction i took the boat out today with a friend and when i got to 3300 rpm he pumped the fuel ball and i increased the rpm all the way to 5500 rpm with no alarm and no slow mode of the engin she ran like a champ! so now my only question is do i replace the fuel pump? and should i do both engines? also is doing a rebuild ok or just replace the whole unit.

 

[ezeke]

Re: 91 150 Evinrude alarm

First, it may not be the pump, but you can test the pump: http://www.maxrules.com/graphics/vropics/VROflowchart.JPG

If the pump checks OK, test the system running to the pump. Without the anti-siphon valve, the pump should be able to handle the demand of the engine unless the fuel filter or the tank pickup screen is blocked. If both motors run from the same tank, the primer bulb could be a possible problem.

The gasoline side of the VRO2 pump is rebuildable using two kits; the part numbers are 0435921 and 0436095.

 

[emdsapmgr]

Re: 91 150 Evinrude alarm

If you had a warning horn relating to excessive fuel hose suction, that could explain your lack of fuel delivery over 3300. Ezeke brings up a good point about the anti-siphon valve. I have seen them stick partially open due to debris/sand in the ball valve. The engine would not pull over 5000. A good cleaning of the valve fixed the problem. Many folks run without them for that reason. I'd pull it off and check it for functionality/cleanliness.