smoke??

[hollowjacket]

I just bought another '63 bigtwin 40hp from another chap and this one works fine, starts right away and runs smooth, even has an alternator!!! (I'll get my money back some other time for the crappy one, the guy that sold it to me is out of town for now). The only problem is that it smokes something fierce He said its been couple months since he used it and it looked like the gas was pretty crappy, could that be all it is and if I run some clean gas through it, it will clear up? I was thinking about emptying a can of carb cleaner and letting it sit for a couple of hours and then running in wot.
What to do!!??
Anyone know what to do?:redface::redface:

Chris

 

[david_r]

Re: smoke??

i would change the wp and lower unit oil along with a decarb heres a link;

http://forums.iboats.com/showthread.php?t=158076

 

[wbeaton]

Re: smoke??

Old gas is a little smokier, but not much. What mix ratio are you using? Running carb cleaner through it won't do anything. You can do a decarb with Seaform, but that won't stop the smoking either. If you are running in a barrel or stationary at the dock it will be worse. It may also be smokey until it warms up. Synthetic oil is less smokey, but more expensive.

 

[Chris1956]

Re: smoke??

Chris, J/E recommends a 24::1 gas oil mix on motors older than 1964. Yours is likely running 24::1. Also, we used to run the gas from last season in the spring. Since the gas had evaporated, and the oil did not, it was really smokey. You might mix up some fresh fuel, and see if it improves.

BTW- I would drop a PM to Joe Reeves amd see if he recommends a 50::1 gas oil mix. On some of the earlier big twins, it was acceptable.

 

[tashasdaddy]

Re: smoke??

63 is a 24:1 motor decarb as mentioned, do not spray carb cleaner or starting fluid in the carbs, this strips the lubrication of the insides. seafoam for a decarb, and premix fuel are the only thing to spray in the carb. using synthetic outboard oil will also reduce the smoke.

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.

 

[mikesea]

Re: smoke??

Another consideration,true the increased oil /fuel mix causes more smoke,also know ,those engines do not realese the exhust throug the prop like newer engines.Therfore the water doesnt absorb any smoke

 

[Chris1956]

Re: smoke??

Mike, The exhaust from those motors is released behind the prop and slightly above the prop. The exhaust is pulled into the water and mixed with the water as the prop spins. There is an idle relief spitter, but even at 24::1 the smoke is not too bad while you are in forward.