Fuel in exhaust

[Vdub144]

I've recently decarboned my 69 Johnson SeaHorse, new plugs, checked gaps, etc. She's running fine on both cyls (I can unplug either and she keeps running). But I am throwing off a LOT of pollution into the water. My gas consumption is up, but not horrifically. I don't think I can lean out any more, or she will lose power. (And as an old motor on an old boat, she's already not setting any sea speed records.)<br /><br />What are my possible problems? Is my high speed just set too rich, or do I likely have some sort of blow-by? <br /><br />I float and run, but I don't want to kill everything in the river for a pleasure cruise!

 

[12Footer]

Re: Fuel in exhaust

First, never unplug a sparkplug wire while it's running, as it can impact the CD unit or the coil, ruining them.<br />If testing, use a spark tester, or ground-out the plug wire.<br />But to address your question; Make sure your choke butterfly is all the way open, instead of partially closed. Then, it may be running too rich.<br />Understand, that most outboards of this vintage are extremely dirty-runners. Emissions didn't even get any thought in R&D until the late 70's.<br />One of the reasons there are so many old outboards still chugging-along, is the constant lubrication provided by mixed fuel. It wasn't until they tried to inject oil, and strictly control the mixture, that motors would tend to grenade shortly after break-in (sometimes before).<br />It's allways better to burn too much oil, than not enough. At least, it is for the motor. The environment is another story.

 

[Yepblaze]

Re: Fuel in exhaust

Take off the hood and run it or pump on the tank primer. Look for leaking fuel lines.<br /><br />It's not uncommon for older 2 stroke outboards to emit a noticable amout of fuel related residues. They even get worse as they get more mature in vintage.<br /><br />One of the qualities of a good two stroke oil is it's dispersant abilities. Sort of makes the mix spread everywhere when it hits the water.

 

[Vdub144]

Re: Fuel in exhaust

Last night while running up the river I tried to lean out both screws without really any noticable improvement. (Really only notice the pollution when I'm standing still.) I am inclined to think that I may have leaky lines like Yepblaze suggests - when I tilt her up out of the water after a trip, I get sort of a flood of 'extra' gas on the water, which would indicate pooling in the motor housing to me. (Checking it out requires borrowing a pont trailer - which I will have to do.)<br /><br />Thanks for the advice on not unplugging while running, 12Ft. A friend who works on motors (not outboards) suggested this for another outboard. (Which we found had a bad coil)<br /><br />I've followed the 'discussion' off & on on "Wal-Mart Oil" and if 'good' oil is necessary. I sort of garnered from all of that the benefit of expensive synthetic is that it doesn't pollute as much - otherwise old outboards (which seem to be 'well oiled machines') can run anything TCW3 rated if you don't care about killing the fish.

 

[Vdub144]

Re: Fuel in exhaust

This weekend I borrowed a trailer and puller er from the water to change the lower unit oil. Only water came out! (EEEK!) So, I think I now know the source of the oil I'm leaking...<br /><br />Additional info: I now have it running fairly well and burning far less gas. BUT, the slightest weeds/muck cause me to spin out. (I throttle down, clean the weeds, get through the muck, then restart and on my merry way.) If I'm in the center of the river, running clean and open, I have plenty of power and don't feel like I'm slipping.<br /><br />Is my lower unit shot, or is this normal? Would just new seals do the trick? Is my prop hub spun? How do I know? (Is there a troubleshooting guide available?)