OK... Did I do something wrong?

[55'Fleetwin7.5]

I warmed up the motor on regular fuel ( in a barrel, with fresh water from a hose keeping it topped off and fresh )... after a few minutes, I switched to about 1 gallon of gas with a whole 16 oz. of Seafoam and an extra 2 or 3 oz of oil. It began to smoke pretty good and I ran it for about 15 minutes or more at a pretty good speed... Well I ran out of gas. I took out the plugs and shot some deep creep in each cylinder and left it for an hour or so.... Got more gas and tried the same except only half a bottle of seafoam... While it was running and smoking up the neighbors... I shot deep creep into the carb... I could not get it to stall!... it would bog a bit but never got near a stall... Ran it for at least 15 minutes... smoke died down a bit. Shut it down and removed a plug... was a bit oily and I looked inside the cylinder and the piston head looked wet and black and not smooth...

What next? I ran out of deep creep but still have about half a bottle of Seafoam left...

 

[Xcusme]

Re: OK... Did I do something wrong?

Sounds OK, but, when you say "I warmed up the motor on regular fuel.... I hope you used Fuel MIX (gas and oil & 24:1)

Next you said: ..after a few minutes, I switched to about 1 gallon of gas with a whole 16 oz. of Seafoam and an extra 2 or 3 oz of oil.
Again, I hope you meant you used 1 gallon of fuel MIX with the 16 oz of Seafoam PLUS 2 or 3 oz of oil. It can make a difference...as posted, you'd be running at a 50:1 mix with added Seafoam.

For the decarb process, always use fuel mix (ratio for your model year motor) with Seafoam added in. Seafoam is not a substitute for the oil.

If I have this all wrong, I'll stand corrected, otherwise it sounds good. I usually do the decarb on the water, not in a barrel so I can run it like I stole it afterwards to blow it out.

 

[tashasdaddy]

Re: OK... Did I do something wrong?

put new plugs in it an take it for a wide open spin around the lake. all sounds normal. told you it was going to smoke.

 

[55'Fleetwin7.5]

Re: OK... Did I do something wrong?

Yes I used fuel mix...not straight gas! I use a 24:1 not 50:1... it is a 1957 35hp and I was told 50:1 was too rich... Sound right? I will tke it out tomorrow... and run it WOT. Thanks for the advice.

 

[cdnfthree2]

Re: OK... Did I do something wrong?

I too have never been able to get my motor to stall with the Seafoam in the carbs. I thought it was strange as well. I couldn't care less though. I decarbed most recently over the weekend and could not believe how smoothly my engine purred at a cruise. It was sweet! New boats don't sound that good.

 

[Tim Frank]

Re: OK... Did I do something wrong?

small point, but richness increases with more oil, so a 50:1 mixture is not as rich as 24:1.

 

[Xcusme]

Re: OK... Did I do something wrong?

Y... I was told 50:1 was too rich... Sound right?

Here's how I see it. The terms Lean and Rich reference the amount of oil in the gasoline.

Take 1 gallon of regular gasoline.

For a 50:1 mix....add 2.56 oz oil
For a 24:1 mix....add 5.33 oz oil

The 50:1 mix is leaner (less oil)
compared to
The 24:1 mix is richer (more oil)

 

[55'Fleetwin7.5]

Re: OK... Did I do something wrong?

Thank you for the clarity...
Makes perfect sense... Thanks.

 

[Chinewalker]

Re: OK... Did I do something wrong?

As for your initial question of why you still have carbon on your pistons - it's been building up for over 50 years now. It'll take more than an afternoon to clean it up. I would do the treatment over again...
- Scott