Seafoam: good or bad idea?

The friendliest place on the web for anyone who enjoys boating.
If you have answers, please help by responding to the unanswered posts.

Fotoman

Guru
Joined
Nov 12, 2009
Messages
649
Just came across a product called Seafoam to clean old engines. I read good and bad reviews about it (more good than bad I have to say). Not really considering putting that stuff in my engine since it runs great but I'm curious to see if others have tried it.

This is the stuff.
https://seafoamsales.com/
 
Pretty well regarded with the car guys....
 
A lot of guys swear by it to keep injectors clean. I use it annually.
 
I used it on a 1971 Ford 351 Cleveland and a 1995 200 HP Johnson Ocean Runner and was rewarded with dramatic increases in performance and overall engine running. Be prepared for a lot of smoke (from the burning carbon) the first time you use it to de-carbonize an engine.
 
Seafoam was a great help in freeing a 12V fuel pump .

To decarbonize an engine an old style Flit (bug spray ) filled with water is excellent.

With the engine warm , use a shim to get the engine running at about 2000RPM

Spray water into the intake till the engine stumbles as it runs.

A piece of news paper under the tail pipe will show the carbon chunks broken loose.

15 min is enough time to clear out a lot of gunk, and stop the running on after the key is off.
 
Seafoan has been on the market since the 50's .. then under another name .. Risoline. Extremely high detergent. Formulated to break down carbon I think.

When I was a young man I'd get outboards free that were stuck/frozen. Using Risoline in both ends I usually got them running fine. May have unstuck the rings but I'm not sure.

It's hard to get the Seafoam to the edge of the piston/cylinder wall interface on diesels as the piston crown is usually very dished and vertical. V type or slant type engines are best for getting the Seafoam to the rings. Of course if an engine isn't stuck cranking it a few seconds should effectively wet the cyl walls.

I think after using it in a way that it would or could get into the lube oil I'd change oil afterwards ... especially at high concentrations. Rubber seals may not like it ... I don't know. But carbon is an abrsaive and after using Seafoam one should get stray carbon away from moving parts.
 
Last edited:
Guys running the rotary engines in Rx-7s uses to swear by it. But then rotorheads are a bit of an odd group. I used to have a squeeze bottle of motor oil that I would use to add a few ounces to the gas tank at every fill up. This was in addition to the oil that would be injected into the rotor from the crankcase while the engine was running.

I think this is why they occasionally would run Seafoam through the engine then immediately change the oil. I was never brave enough to try it.
 
I use a similar product distributed by Mercury marine.

Powertune.
It comes in a spray can and is great for cleaning up carbon buildup, or carburetors or even spot removal when nothing else works.
 
Seafoam is also a fuel stabilizer, works great on my two stroke 2 HP Yamaha outboard and if you are parking your vechiles for a few weeks/months.
 
Us it for my outboard engine and my old 1,000W Yamaha ,,1985, generator. Made a noticeable difference especially on the highly intermittently used gen.

Not in my boat engine though.
 
Us it for my outboard engine and my old 1,000W Yamaha ,,1985, generator. Made a noticeable difference especially on the highly intermittently used gen.

Not in my boat engine though.


Why not?
Did any of you ever use it on their diesel engine?
 
I have. It did make a difference.

Do you mind sharing exactly how you used it and what difference did it make. Were you trying to fix a specific problem? Thanks.
 
I've used it to decarbon outboards and mower engines. Worked great. had a low compression cylinder that came back on a 40 Evinrude. I've considered using it in the filters of my Lehman 120 at next change per the Seafoam suggestions.
 
I'm leery of many of these additives. I have posted a test by Diesel Place several times and some of these highly touted additives actually can do more damage than good.
Sea foam was recommended to me for my outboard by someone I trusted, the local O./B mechanic.
If it screwed up up I could afford the repair/replacement bill.

If it screwed up my main boat engine I would be out of boating.

That's why.
 
Seafoam: https://seafoamsales.com/

And

Berrymans B-12 Chemtool: https://www.berrymanproducts.com/pr...-carburetor-fuel-system-and-injector-cleaner/

IMO - Both of the above products are great for keeping internal portions of fuel lines as well as other internal engine parts clean.

The below product is great for keeping fuel in tank clean, water free and sludge free with no separation.

Soltran: Soltron - The enzyme fuel treatment for diesel and petrol engines

Each are quite affordable and can be picked up in NAPA auto stores. I've been using them for many years having really good results! :thumb:
 
I carry a gallon in the boat at all times, I treat every few tanks just because. I have used the regular sea foam fuel additive in gasoline, diesel and in crankcase oil. I also used the spray can you spray into the intake to clean up the intake, cylinders and valves. I swear by it. I first used it to treat my tanks and clean up my fuel system in the boat, noticed immediate improvement in idle quality and cruise power. That was years ago. I use it in my lawnmower and other small engines to clean up deposits from the E85 fuel if left sitting for too long, haven't had to tear apart a carb in quite a while. Recently bought a car that had been sitting stored for 30+ years, it ran but the oil Control rings appeared stuck and lifters sticking (ticking) Added sea foam to fresh clean crankcase oil and ran for a hundred miles or so. Oil came out black as night, car now runs like new. Also fog carb with the aerosol on all engines. I swear by it.
 
FWIW - Berryman B-12 Chemtool is:


45-50% Toluene
20-25% Acetone
20-25% Methanol
Plus trace solvents
 
Is the Berryman is safe for diesel use? I'd be surprised if it is- given the volatile solvents.
 
FWIW - Berryman B-12 Chemtool is:


45-50% Toluene
20-25% Acetone
20-25% Methanol
Plus trace solvents

Yup - Like I said in post 22 - B-12 is Aggressive!! See the video about Berryman B-12 Chemtool I linked in post 22. That shows just how aggressive it is.

Strips varnish, films and gunk right off fuel lines / engine parts / carburetor and injection system internals. I recommend using per instructions. After getting used to B-12 's capabilities then you can begin to play more with varing concentrations.

I had 4bbl carb that set on shelf for years. It was a gummed up mess. In a bucket I placed that carb for 24 hrs. in 30/70 mix of B-12 to gasoline. That was several years ago... still running that carb with no rebuild since. When I took the carb out of bucket I kept dunking it in the bucket fluid as well as scooping out of the bucket and "Basting" the carb for many minutes. The fluid in bucket became dark as heck. Then I flushed the carb with straight gasoline until there was no more color coming out.

yrmv! :D
 
Last edited:
Yup - Like I said in post 22 - B-12 is Aggressive!! See the video about Berryman B-12 Chemtool I linked in post 22. That shows just how aggressive it is.

Strips varnish, films and gunk right off fuel lines / engine parts / carburetor and injection system internals. I recommend using per instructions. After getting used to B-12 's capabilities then you can begin to play more with varing concentrations.

I had 4bbl carb that set on shelf for years. It was a gummed up mess. In a bucket I placed that carb for 24 hrs. in 30/70 mix of B-12 to gasoline. That was several years ago... still running that carb with no rebuild since. When I took the carb out of bucket I kept dunking it in the bucket fluid as well as scooping out of the bucket and "Basting" the carb for many minutes. The fluid in bucket became dark as heck. Then I flushed the carb with straight gasoline until there was no more color coming out.

yrmv! :D

I do use cleaners such as these when rebuilding fuel components such as carburetors. At that time I would be replacing seals, "O" rings and gaskets which are adversely affected by these solvents. They are good at removing extra fuel deposits on parts by hand.
 
I've used their carb cleaner, but only after stripping the carb to metal parts. (I've got two carbed cars and 5 carbed boat engines). I find that carbs run on ethanol gas stay pretty clean if not allowed to sit for long periods in humidity. However, I wouldn't use the Berryman in a diesel system unless soaking dismantled parts.

While writing this I decided to defer to my friend "Google". Berryman doesn't recommend the B12 in diesel systems due to the volatility and apparently the reduction in lubricity. They appear to have a number of other products formulated for use in diesels.

https://www.berrymanproducts.com/so...-in-my-diesel-pickup-truck-to-treat-the-fuel/
 
I notice many of the pro seafoam comments are regarding gasoline engines. I am not a fan of chemical "cures" for mechanical problems in diesels.
 
Word of caution regarding Berryman's B-12 Chemtool and diesels engines/fuel - B-12 is very flammable!


I'm not sure how flammable Seafoam is... but probably somewhat.
 
I notice many of the pro seafoam comments are regarding gasoline engines. I am not a fan of chemical "cures" for mechanical problems in diesels.


Do you mean quotes like these?...
Just add one can every "XXX" hours or gallons and enjoy these results:
- Increased mileage
- Clean injectors
- Removal of carbon
- Decreased engine temperatures
 
Back
Top Bottom