TOPIC: 1959 Evinrude 35hp

Been awhile since I since I been on here. I have a 1959 Larson Playboy with the original 1959 Evinrude 35 hp motor. Since my last post I have gotten the motor running but I'm having white, greasy, frothy foam coming out of the engine around the bottom half of the engine where the foot bolts up to the actual engine. Does anybody know what could be causing this?

Either one cyl isn't firing and you're seeing all the unburnt fuel and oil making a grey froth, or you have a blown head gasket with water intrusion into the cylinder. After you run it, check your spark plugs for water contamination. If one plug has normal tan/brown deposits and one is clean-as-a-whistle, it's a good indication that the plug is either being washed by fuel or water. Usually if it's a head gasket leak you'll see the nasty foam on the plug. If you see signs of something "off" on the spark plugs, do a compression check.

Ultimately you may need to pull the cyl head for a head gasket replacement, in that case. You'd also need to have the head machined flat or surface the head with sandpaper on a piece of glass.

HTH & let us know what you find...........ed

Pulled the plugs. BOTH look new out of the box and I ran it for 30 mins or so yesterday. No froth, oil or anything else on the plugs not even gray or discolored like they had been ran....Have to borrow a compression tester. That is next. Thoughts??

Does the foam smell stinky or just gassy-oily? If stinky, it's from the L/U gear oil (sulfur additives). If gassy, it's discharge from the engine.

Other things that come to mind are leaking exhaust gaskets or a leaking/damaged carbon seal on the lower end of the crankshaft. Basically anywhere water and oil could mix and be discharged. You could pull the L/U and shine a strong light up the mid-section and get a good view of the lower crankshaft carbon seal. The spring, snap ring, seal should be in place and look intact. Many times I've seen a carbon seal busted in two and the pieces are just hanging in there, not doing their job anymore.

I wouldn't be so inclined to think it's an exhaust gasket leak without seeing water on the plugs, though. So that's a much-less-likely cause.

Update-checked compression. 130 on top cylinder and 125 on the bottom. Found an oil leak on the bottom of the exhaust plate that sits behind the fuel pump. Also while it is running it will idle up some and back down. Will this leak cause the idle problem?

Update #2- New gas tank today and tightened the bolts up on the exhaust plate. No leak on the exhaust plate now. Oily, slimy foam is coming from a water outlet right above where the lower unit(foot) bolts to the engine on the back side of it(Nowhere else am I seeing this come out). Engine had the idle up and down until it got good and hot then went away. Sat there and purred like a kitten.

These do like to be warm n' toasty before they'll idle well. Typical reason why they'd run cold are an open or missing thermostat or missing the spring/check valve in the head. Since it did warm up finally, maybe all that stuff is working OK.

I guess if everything seems normal and it runs well, with nothing on the plugs and no other indications of problems, it might be more of a "normal" discharge that these old motors make. They're not exactly environmentally "sensitive", for sure! So you might see a slight oil slick but a whole bunch of grey froth would be of more concern. Maybe next time you have it out, post a few pics and we can evaluate a bit better......ed

My '59 35hp Evinrude does the same thing. I changed all the seals in the lower unit including upper drive shaft seal. My shift seal was probably original and had the biggest leak during the pressure check. The picture below is from the day after running the outboard on the lake all day. It smells oily and after a few more days it went from a foam look to straight oil. I've been told it's normal, but find it difficult to comprehend it to be normal.
The outboard ran great pretty much all day.

That amount of leakage is NOT normal! Looks like gear oil leakage to me. If you pop the drain plug on the lower unit is the oil still clean, or does it look like that grunge? Do you have a picture of the "straight oil" coming from that drain hole?

If that discharge has a sulfur smell it's definitely gear oil. But if the gear oil is clean, then it's coming from the upper end, because if any oil escapes the lower unit, water will take its place eventually. Lack of water confirms non-leakage.

Normally any oily discharge we're talking about is more of a seepage and maybe it's a good sign that the foam has changed to straight oil, but I'm left wondering how much. If just a small amount I'd consider it normal, but if it's still leaking the same amount as the foam, that's quite a lot. Maybe the engine cleaned itself up as it was run more.

Anyhow, a pic of that would help.............ed