Seafoam resulted in engine knock - why?

[smartwork]

Mercruiser 3.0 - ran very well, but at the suggestions of running Seafoam to make it run "best", we did, and now the engine seems to knock. When varies a little. It's either at idle or just above idle. After that, it's gone. Seafoam was only added to the gas (no engine crankcase flush). I've searched online and discovered others who have encountered this same thing (in a variety of vehicles).

Anyone have suggestions why this surfaced? I've read such things as fouled plugs as well as oil pick-up tube starvation (in the case where people were flushing the crankcase). Could it have cleared out anything to affect timing where it now needs slight adjusting?

Thanks!

 

[Rocky_Road]

Re: Seafoam resulted in engine knock - why?

Not knowing just how much you added to your gas, I would first suspect that you may have reduced your gas octane slightly. If you are using 87 octane you might want to add some 89 to your tank.

Happy boating!

 

[Fordiesel69]

Re: Seafoam resulted in engine knock - why?

After adding the sea foam, during operation, did you hear any ping or octane detonation?

If so, you have lowered the octane of the fuel, thus damaging the engine. Sea foam is a snake oil, does not do anything other than lighten your wallet. You need to use a fuel system cleaner that contains PEA. Look over at www.bobistheoilguy.com under the fuel additive forum for real fuel system cleaners. Then there is always real ways to clean the combustion chambers without using miracle additves.

 

[boattoy]

Re: Seafoam resulted in engine knock - why?

Seafoam isn't snake oil. I've personally had great results. Maybe just added too much. Try some fresh 91. Also recheck timing just to be safest

 

[ohioriverat]

Re: Seafoam resulted in engine knock - why?

I personally would rather run 93 octane for .20 cents more and always have my boat running great! seafoam if used to much will damage accelorator pumps and othe rubber materials.change your oil and run some good grade through it.


92 glastron 4.3

 

[scooper77515]

Re: Seafoam resulted in engine knock - why?

Yes, I agree, snake oil.

Squirting water from a spray bottle into the carb does EXACTLY the same thing as Seafoam.

Yes, I have done it, and torn the engine down to see how well it cleared out the carbon off valves and piston tops. Smokes a bunch, and makes engine run like crap for a few seconds, but really cleans stuff up.

 

[Oshkosh1]

Re: Seafoam resulted in engine knock - why?

I wouldn't go so far as to say it's COMPLETELY useless.

I use it primarily to stabilize my fuel in snow blowers/snowmobiles/boats in lieu of Sta-bil. I've rebuilt several Arctic Cat Mikuni carbs which had what I call "Sta-bil scum" in the bowl. It's a green residue from it being left in there too long. NEVER had an issue with using Seafoam.

Do I think it's some miracle fix all? No...but it DOES have a use.

BTW...I believe that Berrrymans B-12 is a better cleaner in general

 

[mpdive]

Re: Seafoam resulted in engine knock - why?

Yes, I agree, snake oil.

Squirting water from a spray bottle into the carb does EXACTLY the same thing as Seafoam.

Yes, I have done it, and torn the engine down to see how well it cleared out the carbon off valves and piston tops. Smokes a bunch, and makes engine run like crap for a few seconds, but really cleans stuff up.

Use to do it at the dealership all the time. Works great.

 

[rmoore8118]

Re: Seafoam resulted in engine knock - why?

How many hours on the engine? I believe seafoam (or other additives of the like) have their purpose.....to remove carbon deposits on a routine maintenance basis. You may have removed SOME carbon and created "hot spots" on the top of the piston, which can cause ping, or knocking. I use these types of additives, not as a fuel additive, but as a maintenance item. That is, with engine running at mid RPM, pour it in the top of the carb ( carefully, so as not to create hydrolock) until the engine stalls. Let it soak into the carbon for a few hours, and restart on gas only. This allows the carbon to break loose and effectively cleans the combustion chamber. If there are still issues....it's time to remove the head and physically clean the combustion chamber and cylinder ports.

 

[airshot]

Re: Seafoam resulted in engine knock - why?

Seafoam works best in two stroke engines to decarb the cylinders. Usually do not have that problem in four stroke engines. Other products work better in 4 stroke, but seafoam can't be beat in 2 stroke. Seafoam can also be used in the oil of 4 stroke engines to break down sludge buildup and it does work well there. Certain products have certain applications and work well when used that way.

Airshot