1971 evinrude 25 hp

[zach89]

i have a 1971 evinrude 25 hp and when i start it up it smokes like crazy, out of the muffler... am i running it to rich or what i use a 32:1 ratio but was told afterwards to use a 50:1 ratio, what can i do to prevent the smoke?

 

[Rick.]

Re: 1971 evinrude 25 hp

You really can't prevent smoke on a 2 cycle engine. They burn a gas/oil mix and the oil doesn't burn as well as the gas which is a good thing cause the oil is thee for lubrication not for burning. Some have said they notice less smoke using a synthetic oil. If your using a barrel it will appear to smoke more than it will on a breezy lake. I would suggest you try a decarb but if the smoke is already bothering you a decarb will send you running for cover. Don't worry about the smoke. You could be burning a little rich so try to lean out your needle adjustment a bit. Best of luck. Rick.

 

[tx1961whaler]

Re: 1971 evinrude 25 hp

The 1971 model is designed to run at 50:1.

 

[Mas]

Re: 1971 evinrude 25 hp

Besides the smoke, how does the motor run & when was the last time the carb was gone through? Also, check your plugs, they could be fouled by running too rich.

MAS

 

[samo_ott]

Re: 1971 evinrude 25 hp

Good advice. I have the same engine. At least I think it's a '71 but I haven;t fired it up yet! 50:1 and try synthetic oil for less smoke and less pollution as it's biodegradable...

 

[zach89]

Re: 1971 evinrude 25 hp

i have no clue i havent went through the carb or know when the last time it was gone through? i have also tried to run it lean and rich but it still smokes but i will try and replace the plugs just in case they are fouled due to sitting for a year, and the synthetic 2 cycle oil.

 

[Mas]

Re: 1971 evinrude 25 hp

Sounds like you need to go completely through the carb. A gummed up carb will make it smoke more than normal.

MAS

 

[tashasdaddy]

Re: 1971 evinrude 25 hp

decarbing will clean the guts, built up carbon, cause excess smoke. using synthetic oil cuts down on smoke. a reuilt and properly adjusted carb, make it run better and cleaner.

http://forums.iboats.com/showthread.php?t=244013

http://forums.iboats.com/showthread.php?t=167352

Decarb, take a can of seafoam put 3/4 of it in the gas tank, with only 1 gallon of premixed gas. put the rest in a spray bottle. start the engine, and let it come up to temperature. then remove plugs, and them some real good shot of seafoam into the cylinders, replace plugs, let sit 15 minutes. restart, and spray the rest of the seafoam into the carbs, so the the motor almost stalls, wait and repeat until the seafoam is gone.then take for a wide open spin. then put in new plugs, ad premixed gas to the tank, and take it for a wide open throttle spin. it is going to smoke like a house on fire, during this process.