Evinrude Very Smokey

decoy033 · May 29, 2006

Can someone please please help me? I have a 1973 135HP Evinrude that smokes way to much. Then it will die out at idle because the plugs foul out. Oil to gas is 50:1 I drained the tank twice to make sure I put 50:1. Compression in all four cyl. is 140-145. New plugs installed, I put new carb kits on. There is no adjustment on the carbs for mixture. I am about to give up and sell this thing? I am that fed up. Can someone please help?

BoatBuoy · May 29, 2006

Re: Evinrude Very Smokey

Originally posted by decoy033: [q]Oil to gas is 50:1 I drained the tank twice to make sure I put 50:1. [/Q]

. Mix should be gas to oil 50:1. I guess it would smoke a mite.

decoy033 · May 29, 2006

Re: Evinrude Very Smokey

Originally posted by BoatBuoy: 

Originally posted by decoy033: [q]Oil to gas is 50:1 I drained the tank twice to make sure I put 50:1. [/Q]

Click to expand...

. Mix should be gas to oil 50:1. I guess it would smoke a mite.

decoy033 · May 29, 2006

Re: Evinrude Very Smokey

Correction: Gas to Oil is 50:1 (Thank you for pointing that out)

Silvertip · May 29, 2006

Re: Evinrude Very Smokey

Bad fuel pump diaghram sucking fuel directly into the engine through the pulse line.

decoy033 · May 29, 2006

Re: Evinrude Very Smokey

I forgot to mention the fuel pump is new. This thing smokes a lot the oil drips out of the exhaust, this thing makes a mess.

2even · May 30, 2006

Re: Evinrude Very Smokey

I had a similar problem and it was the primer valve was open, if you have the electric primer system check to see if it is not leaking or in the wrong possition.

wildspeed · May 30, 2006

Re: Evinrude Very Smokey

What position should it be ?

Dhadley · May 30, 2006

Re: Evinrude Very Smokey

73's had a choke, not a primer syatem. What spark plugs are you using?

decoy033 · May 30, 2006

Re: Evinrude Very Smokey

Dhadley, I have the choke system as you mentioned. I have installed new champion UL-77V plugs. She wont idle for very long. When I take out the plugs there are full of oil sitting in the ring of the plug and I know that fouls them out, then the engine dies.

Dhadley · May 30, 2006

Re: Evinrude Very Smokey

We might have a case of a weak ignition. If so it might be related to the sensor gap or weak magnet in the flywheel. Lets try some L77JC4 plugs. They're easier to fire. If that helps we may be going in the right direction. Also clean all the grounds. Especially the one on that bracket the coils are mounted on to the block. Then the pack & coin grounds. The cleaner the better. Now, with that said we also need to look at the very basic stuff. I'm sure you know this stuff but it never hurts to not overlook the obvious. We're using 16 oz of oil to 6 gallons of fuel, right? I'm sure you are but a long time ago I went all thru this scenario only to find out the guy was convinced 50:1 was a quart to 6 gallons.

decoy033 · May 31, 2006

Re: Evinrude Very Smokey

Dhadley, I will try this right away.

decoy033 · Jun 5, 2006

Re: Evinrude Very Smokey

Well... When I change the plugs it seems not to foul out as easily. Also what I noticed was when I keed the choke on manualy open it seems to run better and not smoke as much. I know the the slow and high speed orifice are fixed and have no adjustment. Do you know if there is anything else that can be done to get more air into the engine? I just might have to deal with it the way it is. I have an internal gas tank I fill it up half way and add 26oz of oil, and then add the other half, for a total of 10 gallons of gas. (50:1) I wanted to know if the oil is mixing ok with the gas? Or do you think most of the oil is sitting on the bottom and I am sucking it up thicker? Please let me know what you think. I thank you very much for all of you time and help.

emdsapmgr · Jun 6, 2006

Re: Evinrude Very Smokey

Your engine comes stock with huge (73's) high speed jets. The factory jetting flows a low of fuel, and hence, a lot of oil-compared to horsepower produced. You may not be able to change this with the carbs you have. Check that the choke is returning to the completely open position when running. These engines tend to leak a little fuel into the airbox when trimmed for slow/shallow water operation. This fuel/oil mixture gets sucked back into the engine via the airbox silencer hose-further aggrivating things. This engine does not have the recirc system -again, not much to do about it. Check the operating temperature of the engine. Possible that the thermostat is stuck open all the time, causing the engine to run cold and smoke more.

decoy033 · Jun 6, 2006

Re: Evinrude Very Smokey

Thank you very much for your input, I appreciate everyones help here. I'm going to go ahead and install a new thermostat soon here. It seems to run very cool, but also the thermostat opens at 130* F. But I'm going to try. I'm getting there with all your help, she is running better and better. Thanks again!!!

tashasdaddy · Jun 6, 2006

Re: Evinrude Very Smokey

have you tried a decarb with seafoam?

emdsapmgr · Jun 6, 2006

Re: Evinrude Very Smokey

The thermostat could be the problem. Your thermostat should open at 145. If it is opening at 130, as you say, it may be running cool-certainly cooler than the manual calls for.

decoy033 · Jun 6, 2006

Re: Evinrude Very Smokey

Sorry but what is a decarb with seafoam?

decoy033 · Jun 6, 2006

Re: Evinrude Very Smokey

Yep, I'm going to change the thermostat sometime this week. This has got to be done.

tashasdaddy · Jun 6, 2006

Re: Evinrude Very Smokey

it is an internal cleaning of the engine. an engine that old has a lot of built up carbon and gunk. seafoam is available thru the iboats store. use the search function and search 'seafoam' and 'decarb' good luck

Evinrude Very Smokey

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