4.5 hp evinrude smoky and oil residue in test tank

Clendo

Cadet
Joined
Jul 27, 2022
Messages
6
Looking for tips on what would make this small engine have smokey exhaust.(besides too rich a mix) Also oil residue in test tank and water seeping from lower unit seam above propeller skeg.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
47,496
exhaust with unburnt oil is the number one cause of oil residue in a test tank

water leaking means you have a problem you need to fix

smokey exhaust because its a 2-stroke
 

oldboat1

Fleet Admiral
Joined
Apr 3, 2002
Messages
9,607
"mix" can refer to oil/gas ratio or to air/fuel mix. Both can give you those symptoms in a test tank. Have you run that motor out on the lake to clean it out a bit?
 

909

Chief Petty Officer
Joined
Jul 19, 2021
Messages
537
Completely normal ( the water seeping isn't )
Nature of the beast
If you want less smoke, lean out your low jet air fuel mix, switch to synthetic or just get a newer outboard.
 

Clendo

Cadet
Joined
Jul 27, 2022
Messages
6
exhaust with unburnt oil is the number one cause of oil residue in a test tank

water leaking means you have a problem you need to fix

smokey exhaust because its a 2-stroke
So why would there be unburnt oil? Water seems to be spitting rather than a stream on the pisser maybe a bad water pump? I did a 50-1 mix do you think that is too rich?
 

Clendo

Cadet
Joined
Jul 27, 2022
Messages
6
"mix" can refer to oil/gas ratio or to air/fuel mix. Both can give you those symptoms in a test tank. Have you run that motor out on the lake to clean it out a bit?
No I bought it and it sat for a while, just fired it up again after a year!
 

Vic.S

Rear Admiral
Joined
May 4, 2004
Messages
4,699
Looking for tips on what would make this small engine have smokey exhaust.(besides too rich a mix) Also oil residue in test tank and water seeping from lower unit seam above propeller skeg.
What year ? model number ?
I assume from early 1980s ????

50: 1 is the correct fuel mix, using a TCW3 certified oil
Too much oil would make it smokey, but they are smokey when run at low revs in a test tank
Is idle mixture setting correct.
Are carb float and needle valve Ok or is it tending to flood ?
but as said it is normal for unburnt oil to make water in a test tank oily.

I don't understand what you mean by water seeping from seam above the skeg
Surely this model has a one piece gearcase.
If you mean water seeping from the joint between the gear case and the "leg" when it is lifted from the test tank then that is water draining from the leg.. There should be a drain hole ( or two ?? ) along that joint anyway. Check it/ they are not blocked.

This engine does not have a tell-tale. I think what you are calling the "pisser" is the exhaust back pressure relief port on the back of the leg. You should see just a few droplets of water or perhaps a light spray from there.
Nevertheless a new water pump impeller would be a good idea it it has been sitting for a while.
Clean the joint between the gearcase and the leg before you reassemble . No gasket or jointing compound is needed though.
 

Clendo

Cadet
Joined
Jul 27, 2022
Messages
6
What year ? model number ?
I assume from early 1980s ????

50: 1 is the correct fuel mix, using a TCW3 certified oil
Too much oil would make it smokey, but they are smokey when run at low revs in a test tank
Is idle mixture setting correct.
Are carb float and needle valve Ok or is it tending to flood ?
but as said it is normal for unburnt oil to make water in a test tank oily.

I don't understand what you mean by water seeping from seam above the skeg
Surely this model has a one piece gearcase.
If you mean water seeping from the joint between the gear case and the "leg" when it is lifted from the test tank then that is water draining from the leg.. There should be a drain hole ( or two ?? ) along that joint anyway. Check it/ they are not blocked.

This engine does not have a tell-tale. I think what you are calling the "pisser" is the exhaust back pressure relief port on the back of the leg. You should see just a few droplets of water or perhaps a light spray from there.
Nevertheless a new water pump impeller would be a good idea it it has been sitting for a while.
Clean the joint between the gearcase and the leg before you reassemble . No gasket or jointing compound is needed though.
I’ll have a look see tomorrow, I think it is early 80’s evinrude 4.5 with internal fuel tank. Okay I will look for weep holes. Thanks for the info, maybe I’m just being hyper sensitive to the smoke and oil in the tank! Perhaps I just need to run it!
 

Clendo

Cadet
Joined
Jul 27, 2022
Messages
6
I’ll have a look see tomorrow, I think it is early 80’s evinrude 4.5 with internal fuel tank. Okay I will look for weep holes. Thanks for the info, maybe I’m just being hyper sensitive to the smoke and oil in the tank! Perhaps I just need to run it!
Smokier when at higher revs!
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
36,269
Need to understand the basic operation of a 2 stroke engine !!-----When piston is at bottom of stroke the intake and exhaust ports are open.-----Some fresh fuel / oil go right out the exhaust !----This is wasted.-----Collects in your test tub.
 

jimmbo

Supreme Mariner
Joined
May 24, 2004
Messages
12,961
Older engines also used to purge the Crankcase of puddled Gas and Oil, and it was dumped into the Exhaust Housing
 

Vic.S

Rear Admiral
Joined
May 4, 2004
Messages
4,699
Ok - 1more thing, what holds the throttle in place! It wants to slide off like a bicycle handle?
I assume you mean the grip on the tiller
It should clip on.
See the two little holes in the plain part of the grip they should locate on to little clips when its correctly orientated

1659013572845.png
 
Top