225 1998 Salt Water series II overheat alarm

[Oskireg946]

Hi,
Need some help. My 225 2 stroke is overheating. I changed the water pump, thermostats and PCV. The water stream is strong. I tried to flush with water/vinegar. I scanned the heads with an infrared scanner. The port side scanned 192 degrees and the starboard side 132 when the alarm went off. Does this mean the water is not flowing in the channels on that side?
Thanks
SR

[TownsendsFJR1300]

Sounds like it.

We just finished cleaning the water jackets/head of some serious salt water build up in my friends, 2 stroke 200 yamaha. A quick fire up on the lift indicated considerably more water flow out the pisser. We test run it tomorrow, 4,000+ RPM's for the final test.

Pulling the head on his showed two cylinders completly clogged with dried salt. (he rarely flushes the engine), with no water getting around approx 4" of water jacket in the block.

We already replaced the WP (it was due), had a stuck, partially frozen thermostat but still had the over heat alarm and limp mode kick in.


BTW, this was so built up, nothing but plucking with a pick/screwdriver (or blasting it) would remove the build up. Once some soft salt was removed, the newly seen salt hardened up, start picking again. About $150 in gaskets, several hours in labor (the shop wanted $700).

[TownsendsFJR1300]

Update

Well we just back from testing the 200 2 stroke. Ran like a charm. First time I've ever heard it run to 5100 RPM. No overheat alarms, no limp modes, ran like a champ!!

BTW, the pisser is indeed slightly stronger too

[Oskireg946]

Water jacket flush

Sounds good. Well done. I'm going to try flush it with salt away or Rydlime just to see. Pulling the heads off may be too much for me. Did you have any special way you like to flush? Can one flush thru the thermostat housing? I've seen methods people describe by hooking up a tube to the main water tube on the lower unit and flush using a pump.
Thanks
SR

[TownsendsFJR1300]

We tried flushing overnight (recycled city water) thru the upper power head hose. It didn't do much especially after the build up has been there for years. We don't know if the prior owner flushed it much(if at all), my neighbor rarely flushed it (I'm a flushaholic). If the flushing chemical can't get to that really bad spot, it can't run thru. Once I got down in one area of the block, I put a little bit of laquer thinner on a rag and was finally able to see the block finish(no more salt).

The top layer was soft/somewhat wet. The deeper you got, the harder the salt got. We had to literally scrape it with a flat head screwdriver and a sharp (at least 4" long) poking tool (pointy end). It probably took longer to clean the gasket surfaces spotless.

The build up in some spots was the full depth of the cylinder jacket (about 4") around 2 cylinders. If you have the time, some basic metric sockets/wrenches a torque wrench and some time, its very do-able. A small air compressor helps blow all that crap out too..

I can see them charging $7-800 with all the scraping/cleaning, $150 in gaskets too.


What I thought (and may work if its NOT TOO BAD), get the salt away, get the lower unit in a container that will submerge the lower unit with water.
Mix up the salt away per the instructions.
Hook up a small 12 volt water pump (like a deck washing pump) to the flushing hose at the powerhead.
Put the pump in the tank and crank up the pump and let it run and re-cycle itself thru the engine.
Make sure the bucket catches what comes out the pee hole ...

I don't know how well the salt away works, but flushing wise, IMHO, this would keep the salt away moving thru out the engine doing its thing. Certainly can't hurt.

[TownsendsFJR1300]

For my own engine (F150) as soon as I get home (I'm on a canal with a lift). I also have lift extensions so I can reach the lower unit intakes. I put the hose on the powerhead (TURNED OFF) and let the water run 15-20 minutes.

I'll then put it on the muffs and run the engine at fast idle another 10 minutes. I want the thermostat to open up and get fresh water past there and get to ALL the innerds (including the water pump).. Of course a good housing with soap and water on the outside.

BTW, should you have the speedometer pitot tube in the lower unit keep clogging, I took a short (maybe 2') piece of 1/2" hose with a garden hose end and put it on a hand nozzle.
The rubber end of the hose is cut in a sharp "V" to fit over ther pitot tube. A couple of quick shots in the pitot tube with fresh water pistol handle keeps it from clogging with salt. It'll shoot back out due to air pressure in the hose. But now its fresh water and won't salt up..

[Oskireg946]

success!

Thanks for all your comments, really appreciate the time you took to write that. I was getting set to take off the heads when I tried something. I opened the thermostat on the port side. (the overheating side) I had just changed it a few weeks ago. It was full of crud; salt mixed with sandy stuff. Then I saw a plug on top of the head near the thermostat. I opened that and connected my hydraulic steering filler tube and it fitted! I flushed it with a hose for about 10 mins and all the crud came out of the thermostat opening. Then closed everything up and ran the engine in a trash can filled with water and viola; no alarm!!!
So I think the crud was preventing the thermo from opening. We'll see when I try again in a few days and then do a run.
Thanks
SR

[TownsendsFJR1300]

Yep, we noticed that plug on tear down, doesn't go anywhere but into the water jacket. (we didn't remove it). Any crap out is a help.

I'd put your infrared scanner on the engine with it running and check for any inprovement with the #'s. We didn't have that tool but would have been nice to....

BTW, I gather the boast is used in salt water and DO YOU REGULARLY FLUSH IT ? (just curious).

Please post your results and good luck.

[Oskireg946]

Yamaha overheat solved

Yes Scott it is used in saltwater although I have not used the boat for 8 months. It was just sitting at a dock in the intracoastal because the throttle cable seized. So I finally took it out and started working on it. I've had the boat (24" Cobia) for about 6 years. Didn't flush routinely in the beginning but then learned to do it and flushed after every use through the port/hose connection. Seen that people do more extensive flushes though. After this episode will flush more and also seems like a fresh water flush using rabbit ears with the motor running is better as it opens the thermostats/PSV which doesn't happen cold.
Thanks again for your interest.
Sheldon

[TownsendsFJR1300]

I learned that from my old Evinrude V6, 150. I started using the powerhead flusher only. Did use rabbit ears for years-(NO issues) when they came available years ago.

Shortly thereafter, my thermostat corroded up and needed replacement.

Live and learn.

I was really surprised how well that Yamaha 200 ran with approx 40% of the water passsages fully clogged... I don't know of any chemical that would remove that hardened up salt, short of physically removing it...

Good luck and please post your final fix...



BTW, thinking about it, my old boat, I had the manual steering cable freeze up in the housing due to salt water corrosion/intrusion.

After fixing that, I purchased (and subsequently put it on my next/current boat) a greasable fitting with a grease fitting with inner O-ring (forgot the name of it) that slips over the inner steering rod and onto the horizontal pivot shaft end of the engine. Grease her up, keeps the salt water out, steering shaft is like new on a 1996 boat..