Steam from exhaust pipe at the stern

[jmpaok]

I recently purchased a 30' c&c with an Atomic 4. The boat has done quite a bit of sitting for the last 10 years (freshwater in the boating season, on the hard on the off-season). The boat fired up right away and seemed to run ok. I decided since I didnt know how old the impeller was, to change it. The old one looked fine and appeared to be pumping plenty of water out of the exhaust. After the impeller change, the volume of water coming out the exhaust seemed about the same but seemed to put out a little more steam than before. I took the boat out and motored it a bit and noticed the temp creep over 190 so I sailed it back in. I pulled out the t stat which was very rusty and old looking, replacing it with a new one. I also noticed a bit of junk (rust, dirt) in the t stat housing. After changing the t stat the boat now runs 150-160 but still is putting out some steam. engine runs great, no water in the oil, no real leaks. Any advice?

[keelcooler]

You may want to do an acid and power flush to the raw water system. Rust flakes can partly obstruct flow and create a hot spot at the mixer. Some steam is normal. You might observe it dissipate as the water/air and engine heat up.

[sastanley]

I don't think steam is a problem, in and of itself.

I would agree with an acid flush.. Pick up some muratic acid from your hardware store and dilute it then suck it in the motor. If you can retrieve it via a bucket when discharging, all the better.

Another good things that helps is a vinegar flush.

150-160 is a great temp!

[jmpaok]

ok how do I do it?

Havent tried to flush an engine that way before-- Do I let the vinegar or diluted muratic acid suck through before the impeller?(just like the fresh water inlet) and should I try to catch the discharge after the engine or should I let it go through the waterbox and exhaust? Thanks

[Dave O]

Yes through the impeller and the pump. You catch the discharge after the exhaust and before it hits the lake (if you can), for environmental reasons.There are some detailed instructions in the "cooling" section.

Personally I would not use muriatc acid in this case. It is very aggressive and you have to watch handling it including breathing the fumes. An operating temp of 150-160F is very good, so I would be inclined to think that vinegar is just fine and it's safer to handle.

[sastanley]

I agree with DaveO...try vinegar first. Muratic acid was easier on shore, since the conditions are more controlled, and it is easier to hang retrieval buckets under the exhaust to avoid contamination, etc.etc.. - and Dave is also right that 150-160 I think is a pretty good number, hopefully indicating you don't really have any blockages, and vinegar may take care of cleaning out the gunk just fine.

Since it is relatively cheap, I would buy two gallons of white vinegar and suck it into the system as close to the thru-hull as you can. If you have a reliable seacock (I did not until I hauled the boat and replaced it this past winter), pull the hose from there and stick it in the vinegar bucket & suck it until you just about run out of vinegar. That should fill the engine and exhaust with vinegar (another trick I learned is to have a buddy hang over the transom..when he smells the vinegar at the exhaust, you know you've just about filled the system with it..) Let sit & do its magic. Since vinegar is much less caustic, you can let it sit over a beer or three, (or maybe overnight??)...Then either use a bucket of fresh water, or sea water and flush it out...Again, have your buddy either start the motor while you observe, or vice versa to see what comes out!

If you were to use diluted muratic acid, I would only let it sit for 10-15 minutes.

[roadnsky]

Attached is Don's Acid Flush procedure.

Shawn gave a good step-by-step for doing the vinegar.
You can follow this procedure too and just substitute vinegar. Overnight or even 48 hours is a good soak time IMHO.

Also, here's a good previous thread on vinegar (http://www.moyermarine.com/forums/sh...=vinegar+flush)
-Jerry

[jmpaok]

it worked great!!!

just completed the vinegar flush and it worked great!!! Thanks Guys

[sastanley]

Awesome news..thanks for the follow up!

Did you see lots of black goop come out with the vinegar?