Need a Marine Mechanic - 150HP Johnson

[olbarneybasser]

Thanks to those who have replied already...still working on this. Here's the problem...

Motor ran good, then all of a sudden...crap. Stalls, runs rough, all over the place. Narrowed it down to a suspected fuel delivery problem. Bought a VRO rebuild kit and rebuilt the fuel pump.

Reinstalled. Started up, ran a little rough at idle 800+/-rpm. Once over 1000/1100 rpm seems to run nicely. Is it pulling in too much air, then when more fuel is delivered I have right mix? Then after a few minutes...no oil alarm sounds. Killed the engine. Checked primer bulb on oil line...hard. Pulled oil inlet hose to pump...oil is there. Obviously oil in oil reservior. Restart, warning alarm is out. Run a few minutes...bam, no oil alarm again. Exhaust seems to indicate oil is getting there.

So here's where I'm at:

• Want to get it to idle properly.
• Need to be sure I'm getting oil in and kill the alarm (don't care if I have to direct mix in boat tank).

[Gerry Zagorski]

Might be the oil level sending unit in your oil sump... Not sure how your engine works but on the older Mercs they had a float in the sump and it would occationally get stuck, especially after you titled the motor up... If the float sticks it thinks you have no oil in the tank and this would send the motor into alarm and safe mode which would retard the engine and make it run very rough.

[dfish28]

Have you checked to see if you have spark on all cylinders with a spark tester- they are like $20 and worth having, inspected the plugs, made sure they are at the proper gap and clean,does the fuel bulb stay firm after you pump it,just had that issue and 24' of good line later that is good, a power pack on its way out can cause that issue as well(spark tester), sometimes when they go, they start off only intermittently not firing on a cylinder, possibly a coil base timer...

The vro is what went on our powerhead before we got the boat the powerhead was replaced and have done the mix in the tank since, it's just one less thing to go bad on a 97 engine, if you go that route:
On ours the-
Purple,gray,black,brown w yellow trace is the wire colors for the vro plug/alarm on the port side under the starter- bottom plug was it on motor, don't know your year though.

[Foul Hook]

Possible fuel line issue? I was having a similar problem on a merc last year turns out the our favorite friend ethanol made the inside of my fuel line contract so it choked down the fuel supply. Pop off your fuel line at each end and take a look. good luck

[Gerry Zagorski]

Originally Posted by Foul Hook

Possible fuel line issue? I was having a similar problem on a merc last year turns out the our favorite friend ethanol made the inside of my fuel line contract so it choked down the fuel supply. Pop off your fuel line at each end and take a look. good luck

To this theory just get a portable tank and hook your engine up directly to it... If it runs fine you know you have an issue in your fuel lines.

[Rob B]

Check your carbs one might be fouling. Had this issue with my last Johnson and had to rebuild one of the carbs. Rebuild kit was cheap

[jimmythegreek]

those johnsons are notorious for carb issues causing all kinds of problems, and they need FRESH clean plugs, U would be amazed at what kinds on seemingly unrelated things happen. When was the last time u cleaned or rebuilt the carbs? Gerry suggestion of a portable tank is a good idea and so is a spark tester, u may have a miss. Rule out this simple things, the mechanic is gonna do them anyway off the bat and whack u 75-100 an hour as he goes down the list of basics

[jimmythegreek]

also with the mercs like optimax the oil reservoirs like to leak on the seals and cause the vacuum to lose itself and make the alarm go off, even when they are tight the fittings can leak too, most common prob w oil alarms, prob not related to the funny running