I currently run a 1989 Evinrude 150 hp engine on my bass boat.  During the past few outings a constant alarm sounds every once in a while, but only when the boat is near idle.  Once I hit it and get moving, the alarm stops.  It is confusing the heck out of me.  I have done some research online and many say it is a problem with air in the gas line, or just a general lack of gas.  BUT, they also say that when that happens the alarm sounds at higher RPMs' because the engine is trying to suck more gas.  So, I really don't know.  The engine is idling a bit rough.  I am going to change the plugs tomorrow, and see how that goes.  Last time I did that, idle on my other boat was fixed.  I will adjust the idle a bit as well.  Even if the idle is fixed I am still going to have to figure out this error alarm because I can not afford to run an engine into the ground!

The alarm in normally associated with oil problems when you have oil injection or over heating if your not moving enough water through the power head. Hows your water pump/thermostat? I've never heard of an alarm that was fuel related. I had alarm problems on my 70hp Johnson and that's just what it was, a faulty alarm. I replaced it and never had a problem since. It wouldn't hurt if you did call a dealer and find out just what may be triggering the alarm. Might have been a common problem that is easy to fix. Unless you know for sure just what it's trying to tell you, it will be hard to find a solution.

Can't help on PSI gauge, I just have a tach.

The other thing it may be is low water pressure or overheating. Have you changed the impeller or thermostat in the last few years? If not, it may be time to do so. After time, the impeller dries out and gets brittle, or picks up sand and other stuff. When this happens, it cannot pump enough water to cool the motor and will eventually burn the impeller up and cause big problems. This will usually show up while idling because the motor isn't turning enough rpm's to pump water with the compromised impeller. My Merc Optimax has smart gauges that displays water temp, PSI (water pressure at the pump), RPMs, oil, as well as other things. I try to scroll through them from time to time just to make sure everything is working properly. Your question about PSI isn't dumb at all. It's actually very crucial to ensure that the motor is getting enough water pressure to cool it. I don't know anything about your particular motor, but you will definitely want to keep an eye on the water pressure (PSI) gauge - it should be fairly low at idle, maybe 1-3 PSI, and while on plane, maybe somewhere around 10-15 PSI if the impeller is working correctly. You may also have a blockage on your water intake that is restricting water flow. How is the stream from your tell-tale at both idle and on plane?

Rough idling could be a few things. The first thing to check is the plugs as you mentioned. The other things that could cause this is bad gas, water in the gas, plugged carbs, bad primer bulb, restricted gas line, bad fuel pump, or something electrical in the ignition. I would start with the plugs and go from there. Do you run any fuel additives? If not, do so. Startron, Stabil, or Sea Foam should be used in every tank. With the ethanol-blended gas that is used now, it causes all sorts of problems in motors that aren't run every day.

Hello Duke, I'm not sure what the problem is But you can buy a book for the year of the boat ( it is like the gilton book that you buy for cars)... I bought one for my boat and now i do most of the work on my boat rather then taking it to the shop....Out here in Ca they charge $120.00 hr. thats more then i want to pay.Most of the boat shops have them... John

Thank you for the posts, the insight is greatly appreciated. I changed out the plugs like I said, and went fishing. The idle remained rough, and the engine shut down while I was at full throttle. It started right back up, I was not stuck. 07gmcowner the water flow is good at idle and cruising. And thank you for the PSI explanation. The PSI is good, within the parameters that you stated. I did not realize that the ethanol gas could mess with these engines. It did start running poor when I filled it up here. That stuff is at every pump here in Wisconsin. I bought some treatment, and I threw it in last night. I am not going to run the motor until I get a few parts in that I ordered for the motor, just minor tubing and connectors. I think I have a small gas leak in the cables. My plan is to replace the bad connectors and retighten the hoses, maybe using hose clamps instead of the current zip ties in there. I am going to replace the filter also. While following the fuel line from the gas tank, under the deck I found a water separator/filter combo. I was told this is good to have. Is it wise to have an inline filter in the engine, and the separator/filter near the gas tank or should one be removed? Or, does it even matter? Will the engine shut down if it is not getting oil, or just gas....my guess is gas but I don't know.

It will always shut down if it's not getting gas. It will eventually shut down if it's not getting oil. Some manufactures have a "fail safe" system that will either sound an alarm if the oil system is not functioning properly, or combine that with restricting the RPM's the engine can turn. The owners manual will sort that out for you.

Definitely leave the water separator on. On my boat, the water separator is under the hood of the motor, but if you have both that would be even better. Most of the filters can be unhooked and emptied when they are full of water. In the northern climates, the drastic temperature swings can cause problems with condensation forming inside the fuel tank. The warm daytime temps cause the fuel to expand, and at night it contracts and pulls in moisture. After many days/weeks of this, you can end up with some water in the fuel. Add in the 10% ethanol and this problem becomes worse. There are some filling stations that sell 0% ethanol fuel, and it's usually the premium blend. Try to do an internet search and you may find stations around Madison that have 0% ethanol fuel. Another problem that you will find with the ethanol fuel is it hardens the fuel lines (rubber and plastic parts) and after a few years can cause line ruptures or clogged filters.

This is a handy site for finding ethanol free gas.

http://pure-gas.org/index.jsp

Thank you for all of the advice gentlemen, I appreciate it. I got some parts in this week for the fuel lines and I am going to work on it this weekend. I will let all know how it goes.

CHECK OUT YOUR WATER PUMP, ALOT OF TIMES THE WATER PUMP ISN'T PUMPING ENOUGH WATER TO KEEP THE MOTOR COOL. ESPESALLY WHEN AT A LOW IDEL. I HAD THIS PROBLUM 2 YEARS AGO AND I DIDN'T KNOW WHAT THE PROBLUM WAS AT THAT TIME. IT CAST ME DEARLY, I ENDED UP BLOWING A HEAD GASKET THAT ALSO BLEW OUT THE RINGS ON TWO CYLENDERS. THE DAMAGE WAS SO BAD I HAD TO BUY A PARTS MOTOR FOR THE TOP END. I REBUILT THE WATER PUMP, REPLACED THE TOP END, OR THE POWER PACK AS SOME CALL IT. THE TOTTLE COST WAS $1200.00. I DID ALL THE WORK MYSELF. IF I HAD SOMEONE DO THE WORK FOR ME, IT WOULD HAVE COST ME AROUND $2000.00. 
   SO CHECK OUT THE WATER PUMP CLOSELY. BELEAVE YOU ME, THE COST AND TIME INVOLVED IN REPLACEING THE WATER PUMP IS WELL WORTH DOING EVERY OTHER YEAR. A GOOD RUNNING WATER PUMP, MEANS A PROPERLY COOLED AND RUNNING MOTOR. FOR AN AVERAGE OF $50.00 TO $100.00 FOR A NEW WATER PUMP, ALONG WITH ABOUT TWO TO THREE HOURS OF WORK IS WELL WORTH IT.

                                                                                                                                                      GOOD LUCK WITH YOUR MOTOR
                                                                                                                                                         J. RICHARD HANKINS JR.
                                                                                                                                                  A. K. A. THE EVERYDAY FISHERMAN



P. S. 
      TAKE A CHILD FISHING AND CHANGE THEIR LIFE FOREVER.
      GIVE A MAN OR A WOMAN A FISH AND YOU FEED HIM FOR A DAY.
      TEACH A MAN OR WOMAN TO FISH AND YOU FEED THEM FOR THE REST OF THEIR LIVES.
      
      I JUST WANNA GO FISHING.
      I WOULD LIKE TO THANK MY WIFE OF 39 YEARS FOR LETTING ME GO FISHING OVER ALL THE YEARS. ALSO TO THANK HER FOR BECOMING MY FAVORITE FISHING PARTNER. XXXOOO