Black Goo behind Prop after Seafoam

[seedlings]

I ran Seafoam through 3/4 gal fuel, and after a couple of 15 minute run/stop cycles there is a black goo leaking from between the prop and the lower unit. It leaked slowly for about a day afterward and has subsided. I haven't run the motor any more. Thoughts?

1978 70hp Evinrude
CHAD

 

[tashasdaddy]

Re: Black Goo behind Prop after Seafoam

residue from exhaust housing. normal. that is the crap the seafoam is getting out.

 

[seedlings]

Re: Black Goo behind Prop after Seafoam

residue from exhaust housing. normal. that is the crap the seafoam is getting out.

Whew. Thanks again.

 

[Thad]

Re: Black Goo behind Prop after Seafoam

residue from exhaust housing. normal. that is the crap the seafoam is getting out.

+1...Run more through it. If that is what it got the first run through, think how much more is caked in there.

 

[seedlings]

Re: Black Goo behind Prop after Seafoam

+1...Run more through it. If that is what it got the first run through, think how much more is caked in there.

Does running it at fast idle in the driveway do a lesser job of cleaning than taking it out on the water at WOT?

 

[Thad]

Re: Black Goo behind Prop after Seafoam

To get the best of anything, it needs to be run at optimum conditions. For example, you can make a motor run on muffs, but put it under load and it won't run. Same concept here. The engine is running without back pressure and not going through its paces. Plus, I would advise AGAINST running any engine at high idle for an extended period of time on the muffs. Again, a back pressure thing. The engine can "run away" from you, so to speak.
Plus, the engine will work harder on the water, so you will get a better cleaning.
The obvious down side to this is that all of that "goo" will end up in the water.

 

[seedlings]

Re: Black Goo behind Prop after Seafoam

1st run after Seafoam brought the best run yet for the boat. These aren't apple-apple comparisons, but before Seafoam and with the family, 4400rpm and 27mph was the norm with the 17 pitch prop. After seafoam we hit 6000rpm and 30mph with a 15 pitch prop (same family and gear). I've already read that 6000 is a bit high for the '78 70hp evinrude, so I kept it around 5500rpm and 25-26mph.

If you're still curious, try the seafoam - it's "off the ramp".

CHAD

 

[This_lil_fishy]

Re: Black Goo behind Prop after Seafoam

If it's a two stroke merc, it could be gear oil seaping up over the water pump. This happened to me, fortunately a water pump replacement in this case isn't hard, nor expensive. Just annoying. Hopefully it's just the goo being cleaned out of your engine. Seafoam works very well, almost too well. Watch for other leaks that may appear if you've not done any real cleaning out of this engine...specially an older engine. Also watch for plugged carb float needles. As the gunk in the fuel system may foul them.

ian

 

[rw21r]

Re: Black Goo behind Prop after Seafoam

hi,
I used the spray sea foam through the carb, now the motor bogs down anytime i try to accelerate. how would the seafoam end up in the float?

 

[Mel Taylor]

Re: Black Goo behind Prop after Seafoam

My '95, 30 horse Evinrude got to where it wouldn't idle. I ran a full tank (6 gallons) of gas with Seafoam through it in a fifty gallon barrel over a period of several days, changing the water when it got too filthy and either changing it or giving it time to cool when it got warm. I used the amount of Seafoam recommended for cleaning.

I could not believe the amount of black crud that came out of it until the last change of water when it stayed relatively clean.

I thought I had a serious oil leak in the lower unit but couldn't imagine why it was so black.

I also revved it up as much as could in the barrel from time to time.

I was a little disappointed at the end of the run because it still wasn't idling to my satisfaction. BUT, when I took it to the lake it idled beautifully for the first time in several weeks.

 

[Silvertip]

Re: Black Goo behind Prop after Seafoam

SeaFoam is no secret to me. Been using and recommending it for years. It goes into every engine I own.

 

[jay_merrill]

Re: Black Goo behind Prop after Seafoam

Black goo on the prop after Seafoam is black goo that isn't in your engine anymore! Its a beautiful sight!

 

[maddog2112]

Re: Black Goo behind Prop after Seafoam

I`ve used the seafoam in the tank of my car but never on the boat. I assume you can add a can into the boats fuel tank from time to time?

 

[Mel Taylor]

Re: Black Goo behind Prop after Seafoam

MadDog,

It depends on the size of the tank. There are directions on the can. I have a six gallon portable tank, so for cleaning I added twelve ounces - a couple of ounces per gallon. I suspect that three ounces per gallon would not have been too much for that purpose.

Since the initial cleaning I have been running one ounce per gallon as a maintenance measure.

 

[werthert]

Re: Black Goo behind Prop after Seafoam

http://video.google.com/videoplay?docid=6187290865726229173

Huh... never heard of this stuff before.