77ricbaez

Any of you guys have had good experiences with seafoaming these old motors to clean up carbon build up? Don't really believe in these treatments. Had an '87 buick fail smog because of high hydrocarbons. Going to check out the timing and sparkplugs, but I will consider seafoam if it actually works

MDchanic

That means it was running rich, not that there were carbon deposits in the combustion chambers.

That being said, Seafoam definitely does dissolve carbon deposits - I've used it very successfully to clean piston crowns.

I can't say how effective it is with the heads on, but I would recommend pouring a bunch into each cylinder, turning the engine over by hand by hand with a wrench to make sure its well distributed, leaving it for a few days, then repeating a few times, then turning it all the way over, reinstalling spark plugs, and running it.

Nothing wrong with pouring a can slowly into the carburetor (like, over 10 minutes) while holding it on a high idle either, so long as none of your neighbors minds all the local mosquitos being killed.

- Eric

olds 307 and 403

I have had much better luck with Kleenflo Combustion Chamber Cleaner. I will run it through the carb till it stalls and then spray down the spark plug holes and let sit overnight. If you soak spark plugs in it to clean them, that black oily carbon will eventually dissolve off them. I gained 20-25 psi on a couple of cylinders and it unstuck piston rings in a couple of Olds 350's. Also helped stopped piging in my 9.5 to 1 350. Engine flush and Seafoam did squat. This stuff will stay causing extra smoke for a long time till it completely burns out.

MDchanic

Interesting.

Of course, this appears to be a Canadian company, and I don't recall having seen their products in the US.

Anyone know whether the same stuff is sold in the US, perhaps through a different supplier?

- Eric

ELY442

I had an old timer mechanic told me to pour 1 qt of water, antifreeze or trans oil down the carb or take out a vacuum hose and let it suck like a straw to clean out the carbons.

MDchanic

I've done that. It seems like it can help, but if you do it wrong, it can get expensive...

- Eric

olds 307 and 403

I know the Motomaster Combustion Chamber cleaner was the same stuff but more concentrated in a pourable liquid. Again a Canadian product and no longer made. This stuff has a distinct, strong smell. I buy it from Napa, they carry their products here. Acklands said it was not safe to sell in Canada, that means it is the good stuff.

CyberCholo

I have had great success with Seafoam, its probably one of the few of those fixes in a can that actually works.

The 69 Rocket 350 in my Omega had been neglected oil changes at some point in its life and was very gummed up and the oil would get dirty instantly, not only did adding seafoam running the car for a few days and then doing an oil change a few times in a row completely clean out the engine, I also had a noticeable power increase after the first time adding it.

Had a junkyard 70s RV 350 in my 83 Monte Carlo I kind of got ripped off on, I ran seafoam through the carb and after taking the car around the block I had to turn the idle screw down a full turn or maybe more because the amount of crap it blew out meant that the idle mixture just to keep the car running before was now making it run so rich it was idling at like 2000 rpm. For a few weeks after that whenever I would floor the car hard it would blow more carbon out and id have to readjust my idle mixture a bit.

Just adding my two cents but I like the stuff a lot and recommend it to everyone who is dealing with an engine that is sludged up in some way.

77ricbaez

Interesting... I would say my olds could use that to clean it up.

oldcutlass

Seafoam makes a spray fogger.

steverw

Berrymans B12 carb cleaner, works great. Been using it for 40ish years. It does all that.

gs72

Actually high hydrocarbons indicate a misfire or a lean condition causing mifires ( if the CO is low). Hydrocarbons are unburnt fuel. If your NOX is also high then it is a lean condition. A rich condition will show high CO (carbon monoxide) CO is partially burnt fuel and high HC and low NOX because the rich condition will cool the combustion chamber. Another indicator of a lean condition is a high o2 reading. If the NOX is low, cleaning the combustion chambers will yield no positive results towards reducing HC emissions. Basically it boils down to this. A rich condition will show high CO and HC and low NOX. A lean condition will show high HC And NOX right up till lean misfires occur at which point the NOX drops off due to the raw fuel in the chamber. High NOX only is caused by high combustion chamber temps.

77ricbaez

I've seen videos on how much it smokes. My neighbors would call the fire department

Professur

I make it a point to keep seafoaming an engine til after sundown. Keeps the 911 calls to a minimum. The instructions on the can for Seafoam suggest 1/3 in the oil, 1/3 in the gas tank and 1/3 down the throttle. The 1/3 into the oil ... I'm wary of. Seafoam works ... but if that engine hasn't been well kept, you've a fair chance of dislodging something into an oil passage that you'll regret. The 1/3 down the throttle ... only really makes it to the middle of the intake. And that's seldom where the worst offenders are. The 1/3 in the gas tank is supposed to help keep injectors or jets clean. Not much can go wrong there.

It's great stuff ... maybe too good. I like it for regular maintenance. For sorting a serious problem ... well, you play the game and you take your chances.

oldcutlass

The 1/3 in oil, fuel, and manifold is not enough to do anything substantial in cleaning systems. Read the directions on the website.

allyolds68

I bought a 97 Sea Ray Bowrider boat with a 5.7 Mercruiser in the spring of 2015. The boat only had 300 hours but ran like crap. The owner acknowledged this and the boat was priced accordingly. All last summer it started hard. It dieseled after it was turned off when it was hot. It belched black soot when it was started. I checked the compression before I bought it and all 8 cylinders were at 140 so I was pretty sure it was something stupid. I did a tune up, no change. Rebuilt the carb, no change. When I was screwing with the carb for some reason I checked the timing. It was set at zero..... It's supposed to be 10 degrees. I went to advance it and a bracket on the distributor was hitting a bracket on the back of the motor, not allowing the timing to be advanced. I have no idea how long it was like that but obviously someone probably had changed the intake manifold (they was orange RTV squeezed out in a few places), and re-installed the distributor off one tooth. I fixed it and I've been running Sea Foam on every new tankful of gas all summer. At the beginning I was still getting large puffs of soot out every time it started (and it still started pretty hard). By the end of this past summer it's running great. I'm sure the Sea Foam helped clean it out. I don't run ethanol fuel in it at all so that wasn't the reason it cleaned out although it probably would have helped