fuel mixture problem?

[Wizard1]

1957 Evinrude Fastwin 18hp model# 15020
I had a problem with shearing keyways but I seem to have fixed that. I replaced the keyway after shearing a second one and after running the motor for a few Min's I re-torqued the flywheel nut which seems to have stopped that. But I have a new problem, . The motor will run good for about 30 sec's then start missing and cutting out. Plus I noticed that the exhaust seems to have a lot of smoke coming out of it. I was told the motor uses a 24:1 mix of oil and gas. If the oil is mixed to heavy in to the gas will this cause the smoke and the rough engine after running a little while?
Thanks 8)

 

[tashasdaddy]

Re: fuel mixture problem?

wixard 1, 24-1 , 32 ounces oil to 6 gals. is correct, i have a'55 15hp rude, will idle all day, and then run like a scared cat. they are going to smoke when 1st started. when it starts missing remove a plug wire, note any change, then replace and remove the other, and note change. it should run with 1 wire removed. if it does then we know it is not electrical. if it dies you need to check the coil to that plug, when was the last time the carb has had any attention? get back to us.

 

[tashasdaddy]

Re: fuel mixture problem?

has this engine ever had a seafoam decarb treatment? old carbon build up in the cylinders can also cause a lot of smoke. get back.

 

[Wizard1]

Re: fuel mixture problem?

I reworked the carb last year but the motor only seen the water about 8 times due to some other problems I found. I'll try pulling plug wires (one at a time) to see what happens. I have never done a decarb to this motor and I will need to find out more info on the subject before I attempt it. I'll let you guys know what I find out. It will be Friday due to the fact I have to work the next two days
Thanks for the quick response guys 8)

Does anyoe know where I can find a blow by blow description on how to decarb an older motor?8)