Rough Idleing & Lots of Blue Smoke... What Gives?

I got a 1995 Johnson 90 hp outboard which has been giving me loads of problems over the past 2 weeks. Last week I had to replace the starter selonoid due to some faulty electrical wires which were shorting out. Now the engine works, but when idleing it runs a little rough and kicks out lots of blue smoke. When in full throttle or at cruising speed, there is no indicaiton that anything is wrong, and smoke is minimally noticed. Also, when I throttle back to a trolling speed after a long haul to my fishing area, it will take 5 minutes or so before I notice the smoke again.<br /><br />Two things come to mind which could shed some light on the matter. First of all, I have replaced a number of electrical wires due to the insulation breaking off on them. I am fairly good a soldering, so I am confident that the wires replaced are working fine, but I could always double check my work. The other thing that comes to mind is that I fish up on the sand flats quite a bit, therefore the engine sucks up quite a bit of sand at times. This may or may not have anything to do with the problem, cuz the engine runs cool as a cucumber even while sucking up the occasional sand buffet.<br /><br />Any ideas? Thanks in advance!

Re: Rough Idleing & Lots of Blue Smoke... What Gives?

One additonal note... I had a problem replacing the wire for the WT Sensor on the Port Cylinder Head. The bolt holding the wire to the cylinder head had ceased and could not be removed. As a temporary fix, I scratched the head of the bolt, then put a beed of solder to hold the new wire on (as all the insulation had peeled off the old wire). Per my seloc book, if the wire is not making good contact, it could result in excess smoke. I suppose replacing this sensor wouldn't be a bad idea eh?

Re: Rough Idleing & Lots of Blue Smoke... What Gives?

when it is running what does your volt meter read??

Re: Rough Idleing & Lots of Blue Smoke... What Gives?

As far as I have noticed, the voltage meter pretty much always stays the same. It almost always stays at 12volts with few fluctuations, but I could always run it up again in the morning to look for any discrepancies.

Re: Rough Idleing & Lots of Blue Smoke... What Gives?

Is your motor a VRO oil injected?<br />Maybe some sand got into a thermostat holding it open (over-cooling).This may create a rich condition at slow speeds.

Re: Rough Idleing & Lots of Blue Smoke... What Gives?

It is VRO oil injected... any idea how one would test the thermostat. I am looking in the Selok book and cannot find much info on it.<br />Thanks

Re: Rough Idleing & Lots of Blue Smoke... What Gives?

About the only way to test the thermostat is to remove it, place it in a pan of water, heat the water and observe it opening. Use a candy thermometer in the pan to verify the opening temperature.<br />Backlash

Re: Rough Idleing & Lots of Blue Smoke... What Gives?

Any airleak on fuel lines will cause VRO to overoil and can for sure cause rough iddle and smoke.<br /><br />VRO pump compares number of fuel pump strokes, and vacuum to do a number of oil pump strokes.<br /><br />I'd advise you to check you fuel lines, primer bulb and connectors. OEM hose, clamps, bulb and connectors are best.

Re: Rough Idleing & Lots of Blue Smoke... What Gives?

i have noticed a bit of oil around the boat inside the harbor recently, so it is for sure leaking a bit of oil (its definatly not gasoline). I cannot figure where it is coming from for the life of me though... will have to inspect more closely, but it is definatly leaking out from inside the engine cuz it is leaking out of the case (only a drop or two at a time, very very very slowly).

Re: Rough Idleing & Lots of Blue Smoke... What Gives?

If it is only a few drops out of the air silender, a lot of them does that. Look at the buttom of silencer box. It doesnt have to drip if fuel line leaks, is has vacuum most of the time, but squezing primer bumb might make it. Connectors can however be tight under pressure, but leaking under vacuum.