Engine Descaler

[rcnight]

Gents: ever descaled your engine? Good idea or not worth it? If yes, what product/method worked best for you? Also, what is the safest way to do a general cleaning of the power head?

[flyingfrizzle]

I do all of my older Cerebrated and EFI outboards. Not sure if I would try this on a DFI motor. Yamaha and Mercury sale a "Decarb" solution but I have found seafoam works good as anything and cost less. If you google "decarb outboard" you will see what others do but what I do is the following with good results:


Mix one 16oz bottle of seafoam to one gallon of gas.
Unhook fuel line from outboard and place in the gas can or container with the mixed seafoam solution (add heavy oil if you premix).
Start the outboard up and run it at a high idle (low idle may choke off)
Let the full gallon of solution pull in the outboard.
Keep throttle up to keep from stalling and yes it will smoke bad.
Once done hook back up fuel line and change spark plugs.


Like said it will smoke heavy but it dose blow the carbon build up out of the engine. Last one I did it left a black streek about two foot long on the ground behind the prop (did decarb on the muffs). All that was in the engine on the piston tops, rings and in the chambers. This will also help outboards that have sat a long time with possible stuck rings. I have also read where people run their fuel low then add a few cans to the gas tank in the boat and run the engine wide open under load up the water way and then put back on the trailer and then fill up with fuel. Many ways to decarb an engine but I like the seafoam concentrate method.


When I was young and in high school I worked at the local GMC Cadillac dealership and they decarbed or descaled the engines also. What we did there as pull a vacuum line from the throttle body and hook up a hose to a can of GM decarb solution and then flip it over while holding throttle at an high idle. Let it suck the can of stuff threw the engine and then clear the ecu for misfire codes and run the car to check to make sure misfire codes did not come back. They did this when people complained about ruff idle or if the computer scan showed certain codes. They charged around $100 to do this and it only took 15mis. A big money maker for them. They sold that service a lot back in the late 90s early 2000s. Not sure if they still do that now or not.

[uncleboo]

Seafoam also has a top end cleaner/decarbonizing product, complete with nifty straw for spraying.

[DonV]

I've done my old Merc EFI 2S, however you talking about the 4S Zuke?

[rcnight]

Gents: while I’m sorting out the cooling system on my used DF225, thought I’d see about flushing/descale it. Got a overheat alarm on the hose so replacing the usual. Thought I try to cleanup the innards. Any suggestions?

[Old'sCool]

Salt away or similar. West has their version. I think there's a vinegar recipe out there also.

[flyingfrizzle]

I was thinking you were talking about the engine carbon and didn't realize you were referring to the cooling system. I don't have any tricks on that really

[uncleboo]

ditto

[Enyar]

I'm not sure it's what fixed my motor because I replaced thermostats, water pumps, poppit valves at the same time but this is what I did.

I pulled the lower units off and plugged the pickup tube. Then I pulled the thermostats. Filled the motors with vinegar (just regular 5% from the store but I now realize that you can get 20 or 30% off amazon). Let it sit for 10 minutes then pull the plug from pickup tube and let it drain. The stuff that drained I caught in a bucket and reused a few more times before finally flushing with fresh vinegar the last time and then flushing with fresh water for a long time.

A lot of stuff came out but who knows if it made a big difference. In the past with the 60 hp on my whaler I flushed it in a small garbage can with water and vinegar and that also cleaned a LOT of stuff out. I tried this with the 225 2 strokes on the big boat but I don't know that it was that effective because the garbage can is just too large and I didn't want to buy 40 bottles of vinegar. One thing I think could work well is a bucket with an aquarium pump, water heater and vinegar. If you could rig it so that the pump was constantly flushing hot vinegar through the block and then recapturing the vinegar to keep recirculating it I think that would really clean out the innards.

I now flush with saltaway after use, not sure how effective that is either. Just doing everything I can to keep these old motors running because a repower is too much $$!!