smokey outboard

T

Tips Up

Well-Known Member
I have a mid 80's 60 horse Johnson outboard on my boat. Motor runs well.

This year it seems to be putting out a lot of gas fumes. It is a bit smokey as most older 2 stokes but it has a real gas smell to the fumes and I have to open the front canopy hatch and side windows when idling or running slow.

I have had the motor for 3 years and it was not a problem in the past. The only things that have changed are: I got a tune up at the end of last year and had the carbs adjusted to idle slower and troll slower and I had a new soft top installed.

Maybe just running too rich?

Any advise/ ideas appreciated.

Thanks

Tips
 
adjust your carb. its probally way out and fouled your spark plugs
 
that seafoam stuff works great. i did some seafoam on trucks engine right before i rebuilt it. when i took the heads off the pistons had major amounts of carbon that was ready to flake away. it cleans out your engine and get rid of carbon. run the engine for about 7 mins then pour about 1/2 can thru while running (trying not to flood it) then flood then engine untill its stalls. then pour a bit more into the carb(s) and let it sit for atleast 5 mins. then crank tills it fires and carbon will pour from your exhaust
 
Definitely sounds like you are running rich. Check to see if your carbs are flooding at idle. If the boat has not been run for awhile it may just need a good run. If your motor sat over the winter there is a good chance there may be old fuel to blame. The older evinrude and johnsons were pretty much bullet proof. I have found larger outboards don't really like to idle for extended periods of time without accumulating excess fuel. I had an older 82 evinrude on 16 double eagle and tried to turn down the idle for trolling and had pretty much the same problem. I finally mounted a kicker bracket on and turned the idle back up. You can also check the spark plugs for signs of fouling or wetness as this is a good indicator of overfueling. Good luck.
 
I forgot to mention that through the 80's omc had an accordian seal/boot from the exhaust to the lower unit. The seal/ boot did sometimes leak. Easiest way to tell is to take the cover off the motor and see if it speeds up signifigantly. This saves taking off the lower unit to test. You will also smell a stronger than usual gas odor under the engine cover if it is leaking. If really in doubt still try giving Lordship marine a call. They are awesome and very free with their knowledge in my experience.
 
Thanks for the responses.

The motor runs great other than the extra smoke and smelly fumes. The boat never sits for long. I am on the water most weekends. I noticed gas on the water around the motor yesterday while idling.

I am no mechanic so I think it will be a trip to SG Power this week. I am sure it is just a carb adjustment issue as the motor runs great, is very clean under the cover and trolls and idles well.

Tips
 
from what I've read and seen, big 2-strokes don't like to be kept at low RPM and can foul up with uncombusted fuel.
 
Hey there tips up good luck with your motor. More details definitely make it easier to trouble shoot. Taking your motor to a professional is not a bad move. I am a heavy duty mechanic by trade and have done the professional outboard route myself as outboards can be a tricky animal. If your motor runs well as you have said it may just be a simple carb adjustment. Running a motor rich is not bad for the motor and too lean will burn out pistons but there is a point where too much fuel is bad and a rainbow behind your boat is not that good for the ocean. I live on the mainland and do not have any experience with sg power but most dealers are very competent and with a 10k minimum for a new replacement a trip to the dealer for work may not be a bad alternative. Good luck.
 
If the soft top is new or a different design then you might be experiencing the "station wagon effect" where fumes are sucked in due to the change in air flow. Try running without the soft top to see if the situation continues. I had a canvas setup on an inboard that made cruising at certain speeds really uncomfortable. Carbon monoxide is dangerous and is part of the exhaust gases.
 
The top is new and may create a vaccuum but even with the side windows removed and the hatch over the driver open it is still smelly. Also there is gas sitting on the water around the outboard when idling at the dock. Seems like a lot of unburned fuel to me.

I dropped it off this morning at SG for servicing. I am hoping they can fix me up. I guess I will have to go fishing tomorrow to try it out!

Thanks again for the feedback.
 
I also used to have a mid 80's Johnson 60hp 3 cylinder
The motor did not like to idle down low enough to troll.
the plugs would continually foul.
The motor eventually died (bent crank)
went to a Honda 4 stroke and never looked back :D
 
The diagnosis...

Faulty primer valve.

So after replacement of that, some carb adjustments and a few $$.

We will find out tomorrow.

Tips
 
Good luck with your outboard. Hopefully sg found the problem. A fresh carb adjust sounds like a darn good excuse to go fishing to me. I have used the same one with my better half. Luckily she likes to fish and is know to use the excuse that old outboard fuel isn't good so we should go burn it off. Any reason to fish is a good reason.
 
I have a Yamaha 8hp Four Stroke that has started running rough and dying at low speeds. If I run it wide open for a couple of minutes it will then run nice and smooth for a while at trolling speed but eventually will do the same thing.

I stopped by the mechanic shop and they said the carb is dirty and needs to be taken apart and cleaned and/or rebuilt. Will a product like Seafoam clean it out without having to take it apart etc?

Thanks, Slabby
 
quote:Originally posted by Slabby20

I have a Yamaha 8hp Four Stroke that has started running rough and dying at low speeds. If I run it wide open for a couple of minutes it will then run nice and smooth for a while at trolling speed but eventually will do the same thing.

I stopped by the mechanic shop and they said the carb is dirty and needs to be taken apart and cleaned and/or rebuilt. Will a product like Seafoam clean it out without having to take it apart etc?

Thanks, Slabby
Click to expand...

that, and also how long was it since you replaced your spark plugs?
 
Well the story continues...

Put the boat in the water at Cheanuh on Saturday am and it started up well. The smoke was noticably less and not too smelly!!

I trolled out past the log boom and hit the throttle... nothing. It would not power up?! I checked the tanks to make sure the air getting in ect...switched tanks... Nothing.

According to the work order they had replaced the primer valve, carb adj and cable adj. So I called the mechanic, explained the problem and asked if there was anything I could try as I was in the water and wanted to go fishing. He walked me through adjusting the cables but nothing worked. So they said bring it right in.

He had a look right away and decided that my throttle cable was stretched out and needed to be replaced?? Seems odd to me as I clocked the speed at 32 mph last week and now it won't go 5 mph??
You would think that a cable would stretch over time not all of a sudden?! The mechanic and the desk guy were less than accomodating so I trailered home and went back in today to make arrangements with someone else.

So they have to order parts and I have to take it back in. I don't understand why they would spend time and charge me for cable adjustments if my cables are shot?! And why they would not have diagnosed this problem while it was there the first time. Power has never been a problem on this boat. It comes out of the hole very quick.

So at the end of the day I have spent 4 hours of my Saturday, $8 launch, gas from my house in Goldstream to Cheanuh to town and back home, and I have a boat that doesn't run. [B)]:(

I am hoping for some compensation for all of my trouble and/or service time that I payed for on the first bill for adjusting cables. This remains to be seen.

I have had good experiances and good service from SG in the past but so far this has been a bad one. We will see how it comes out at the end of the week.

It's like a kick in the nuts when you take a running boat in to a shop and it comes out not running.

Hopefully have something better to report by the weekend.

Tips
 
Had a similar problem early this year. I replaced both fuel filter and all spark plugs to no avail... It turned out to be a dead fuse for the fuel innjectors. Cheap fix that caused a lot of problems prior to finding the cause. I hope yours goes that well.
Good luck
 
Finally all is good.
I took the boat back in and it turned out the cables are fine. There was water in my gas and in turn in my carbs. At first I was not sure how this could happen and why it ran fine before taking it in for the first service.

In the end I had it explained to me that water is heavier than gas and seperates like oil and water. It was in the bottom of my tank which I almost never get to and could have been there for a long time. I had the carbs removed and cleaned, the engine flushed and bought a new tank.

They gave me a bit of a break on the service and new tank for my troubles and most importantly explained everything to me and got me up and running.

It was cooincidental that these problems occurred back to back and they were not related.

I am glad I dealt with it rationally as I would have come out the fool if I had lost my cool. The customer service I received in the end was good and my boat is now running better, cleaner and has more range to the throttle than before.

Tips
 
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