Evinrude 15hp OB Motor smoking

Birdface · #1 (**permalink**) 09-13-2008

Hey everyone,

I'm on the verge of spending $1,200 just for sanity's sake. And, when you spent $3000 for the purchase of the boat that's a significant investment.

I have a Evinrude 15hp 2 stroke outboard, the PO tells me it was "rebuilt" in 1986 but he doesn't know the actual year of the motor.

Anyway- it's run pretty consistently and without much trouble for three years. I've had some fuel line/air/coupling issues but those have been resolved with a new tank, connectors and hose.

This year, I feel like the motor has been smoking more and more. It's a white smoke with "normal" smell, but on watching neighbor's boats I'm realizing I'm smoking much more significantly than other 2 strokes in my harbor.

I normally mix 2.5 oz of oil per gallon of fuel. I know a rich mixture will cause smoke, is this a high ratio?

Today we refilled with 2 gallons and I threw 5oz of oil in and then we took a spin on outboard only. The smoke seemed worse than ever... so we moored and I took a closer look. My water pump seems to be working fine, I have a steady and strong water exhaust coming off the motor. But I noticed today for the first time that out of my smoking exhaust there is also some water spray. I felt the water and it was warm to the touch....

I have probably three or four more sails in me this year before the yard can take a closer look while they winterize the outboard. But my next sail is with my father and Aunt, both of which aren't sailors and I need to know my motor is sound and not an issue.

I'm more of a newbie with outboards than sailboats... so that's a bad sign, but I guess I'm just writing to see if there's anything significant to worry about, an easy fix or test to run, or just to have my mind put at ease.

I think my overall plan is to put this 1986 on a stand in my basement, buy a 2005 4 stroke or newer and use my 1986 as a learning tool/project motor. But that can't happen in the next few weeks.

Any comments/suggestions are welcome.

Freesail99 · #2 (**permalink**) 09-13-2008

Quote:

I think my overall plan is to put this 1986 on a stand in my basement, buy a 2005 4 stroke or newer and use my 1986 as a learning tool/project motor. But that can't happen in the next few weeks.

Sounds like a good plan. It sounds like you have a 30 year old outboard motor.

jgeissinger · #3 (**permalink**) 09-13-2008

Actually, your oil/fuel ratio is just about right at 50:1, where it is supposed to be. When you say you have warm water coming out, do you mean in a steady stream from the "pee hole" or just spitting out the exhaust? Take the cowling off after you have run it a little while and see if you can touch the cylinder head. If it is too hot to even briefly touch, that's not good. I am concerned that the smoke is white, which is very often an indicator that it is part steam. It could be a water pump, a thermostat, or something else equally simple.Don't give up on the motor. They will run a very long time with minimal maintenance, and you can do a lot of work yourself.

Birdface · #4 (**permalink**) 09-13-2008

JGeissinger,

This is a common piece of advice I get from people "in the know". Don't give up on the motor... I'm a computer engineer but I don't know the first thing about outboard maintenance. So even the smaller repairs feel somewhat risky for me.

I have a steady stream from the pee hole, it's generally been cool water coming out. I've had to clear that from time to time with a small piece of wire but it's running well now.

From the exhaust I have the warm spitting/spray coming out and white smoke.

jgeissinger · #5 (**permalink**) 09-13-2008

Well I will have to admit that it beats me. If the pee hole is a steady stream of cool to warm water, and it runs ok, there probably isn't anything fatally wrong. Just for my own curiosity I will run this by a real Johnson/Evinrude expert that I know and see if he has any bright ideas. I'll let you know what I find out.

sailingdog · #6 (**permalink**) 09-13-2008

Could the cooling passages of the engine have a pinhole leak???

Birdface · #7 (**permalink**) 09-13-2008

So moisture in the exhaust (warm misting spray) is a problem to worry about then, I'm assuming?

I have a second tank of gas, I'm thinking of mixing it extremely lean and using it to see if the smoking persists.

Thanks for checking things out with your Evinrude tech, I do appreciate 2 stroke motors, and I understand they're near impossible to find now.

I also wouldn't mind avoiding the $1200 bill for a 9.9hp 4 stroke. I just took a similar financial hit on my rudder re-fab.

Thanks guys,
-M

Birdface · #8 (**permalink**) 09-13-2008

Just a follow-up from research, it seems like most people say white smoke is water related, but a number of people say oil can cause white smoke too.

One post mentioned the seal on the clutch end of the crankshaft leaking oil causing the problem.

Still confused though due to the water spray from the exhaust.

Others said there could be water leaking into the combustion chamber. The worst said cracked gasket or similar allowing water from cooling system in.

Could simply be bad gas too I guess? Empty somewhere(?), clean and refill?

timebandit · #9 (**permalink**) 09-14-2008

More smoke---
My two stroke call for 100:1 (1987) Yahama, so I will show less smoke.

All two stroke motors will show more smoke when you first start them up. It is left over oil suck to the engine walls from when the motor cooled and the gas evaporated.

Are you sure the exhaust is commming from the pee hole or from and exhaust hole just under and centered on the bottom of the powerhead. It seems that when at and idle in nuetral there is not enuff suction at the prop to pull the exhaust through the prop under water and it is designed to exit through this hole. The pee hole is just an indicator that water is flowing--most of it exits underwater, cooling the exhaust.

You might try changing you oil brand, check your plugs, and run fresh gas.

I don't think you have a problem at all.

Rick

lbdavis · #10 (**permalink**) 09-14-2008

Birdface,

I'll cast another vote for not giving up on this engine. You are likely to still get more years out of your ?30? year old 15hp, than out of a new four stroke. New four strokes run great, for about 4 or five years.

As long as you haven't damaged cylinders or anything, you will run that old 2 stroke for a loooooong time for minimal maintenance.

One thing I would research is your oil to gas ratio. Not all outboards are 50:1. Do a google search and try to estimate the age of your engine by pictures you see on the internet. Then find out what type of ratio you need. Many older outboards ran on 30:1.