Saving Old Seagulls

I've just returned from a trip with my Seagull 90 and an inflatable boat. I ran the motor for more hours in 10 days than it had seen in the previous 29 years. Running a lot of hours meant a lot of oil emanating from the the exhaust on return to shore. I think I made this worse by running Amsoil synthetic outboard oil which mixed with the water to form a coffee brown sludge, similar to what a blown head gasket might produce in the sump of a car. The oil was great for lack of smoke and smell, and the gunge produced quickly broke down in the water with know oil rainbow whatsoever, so it may have been good for the environment, but less so for my truck interior. A lot of nasty gunge would continue to eminate for some time after coming a shore and made the loading and transporting of the motor difficult as well as subsequent storage. It never seemed as bad with the mineral oil used before, but then I've only run that for short periods as an auxiliary motor - that did at least look like oil when it came out. The motor ran flawlessly with great fuel economy and the spark plug was clean with a brown tinge to it indicating a clean burn and correct mixture.

So my question as to the best 2 stroke oil is what has worked well for others regarding minimum mess at the end of a days use?

not to sure what others think but I do a lot of long runs with mine and they tend to be pretty messy at the end

Do you get the oil emulsifying? the mixing with water seems to dramatically increase the volume of oily gunge, but I haven't run far enough on mineral based oil to have a true comparison. Because the exhaust temperature is low, I'm guessing the oil doesn't burn off like it would in a 2 stroke motorcycle, and mixing with the water only makes it worse by increasing it's volume.

The Amsoil oil your using, Is it 100% Synthetic>>> Or is it a synthetic blend

All 2 strokes are designed to expell unburnt oil from the exhaust!

Very very little 2 stroke oil will burn at the combustion temperature & pressure of a Seagull, because it doesn't readily vapourise!

The only way to stop this horrible run off, is to stop mixing oil with the petrol, not too good for Seagulls!

Lowering the amount of 2 stroke oil below the manufacturer's recommendation could well shorten the life expectancy of your Seagull considerably!

Seagull outboards have a total loss lubrication system, what goes in has to come out, somewhere.

If you want a non drip outboard, buy a four stroke!

Seagull droppings.

Reducing the amount of oil in the fuel will enrich the mixture - your motor will run rich. Unless you're running a Bing carburettor of course.

I have to wonder if a mixture that's too rich could lead to more unburnt fuel exuding from the exhaust....

"What goes in must come out" about sums it up, the motors do run incredibly cool, my 90 flows a huge amount of water even at idle and the water stream is barely warmer that what's going in. So other than a hint of 2 stroke smoke, most will come back out - as most of it seems to emerge once a shore it could be seen as an environmental benefit as it's not being burned and blown into the water

While the problem is inevitable, there must be some oils that burn off better and/or by not absorbing water can reduce the size of the issue.

On the basis that so little oil is actually burned, it might seem tempting to reduce the amount of oil put in with the gas on the basis the internals should be swimming in the stuff, but this seems to be almost universally held to be a bad idea, so sticking with the 25:1 ratio is the only sensible option I see, since unless you have time and the desire to run on different oil ratios and then strip the motor to see how much lubrication is on the internals, today's running fine is tomorrows seizure or other expensive repair. With considerable "surplus" oil in the system you would I feel get a gradual delayed reduction in overall lubrication as the "surplus" depletes running on a higher ratio, so it would be very difficult to gauge what was really going on at any particular point in time and the "successful" runs achieved on a reduced oil could turn quickly to severe damage after extensive use. You also need to be able to compensate for changes in mixture if the fuel entering the carb is thinner due to reduced oil content.

Although the plug color was pretty good on my motor, I still think it's running too rich with the altitude, it seems a rich mixture could increase oil output beyond the obvious, more fuel in, more oil out, because a richer mixture can also reduce combustion temperatures causing even less oil to be burned. I see there are 2 jet sizes for the 416, mine runs the 95 size, is the 90 smaller? and are these jets even available?

If your mixing 25:1 with a mess resulting, you have a too rich running issue I think. I would stay at that ratio and investigate further.

as far as

"All 2 strokes are designed to expell unburnt oil from the exhaust!"

I have had nearly 80 gallons of fuel thru this exhaust since last prop pull to lubricate the spline.........even the nut and split pin is still dry. I painted the inside so as to check at a glance if there was a problem in combustion years ago.


The other pic (1st one) is the last, on boat Riptide that used a tank and a half of 3/4 pint to the gallon mix. No oil out of exhaust either.

I might just add that only my beloved Seagulls ALWAYS have something dripping out. It is the nature of the bird I think. I just mix for each motor.

Also, see my vid of one of my Muncies, it is running in a tub at the end. The mix is amazingly 1 pint to the gallon......no smoke and no oil left in the water at all.

http://www.youtube.com/watch?v=c1H38kde ... ature=plcp

Cheers

B

If your going to ask questions like this you have to give us all the facts Bruce.

Compression in lbs, oiled 3 pulls?
Looped or cross scavanged?
Watercooled head?
Type of bore cast iron steel liner?
Ring type?
Water in exhaust?


In Seagull terms I would say that it's running too weak & would expect to see signs of piston dragging, after a few hours of full throttle, full revs work.

One of the moderator's jobs is to ensure that posters are not lead up a gum tree, to do that in this situation we have to ensure we are compairing like for like!

Compairing a Seagull plug with a chainsaw plug or something similar is going to paint a very inaccurate picture, a high compression, high temp, looped charged combustion motor is going to give very different combustion situation to a Seagull.

Because of the low temperatures in a Seagull, the fuel is not vapourised very well above the piston, leaving little opportunity for lube deposition on the cylinder walls & piston crown.