1989 115 ETLF Overheating

[CentralTexas]

I’ve owned this motor since new and have run it about 50 hours per year. Except for the normal carburetor rebuilds and water pumps it has been trouble free. Well maintained and always winterized. It gets run mostly in fresh water with about 10 trips to the Gulf over its life. Engine was always flushed after my trips to the Gulf.

My problem is an overheating alarm when running over 4000 rpm. After about 2 minutes alarm sounds and rpm drop. Alarm shuts off after about 1 min. If I keep it under 4000 it will not sound the alarm. New water pump assembly – no change. Tell tale is strong. Original Tstats, pressure relief valve and temp sensors. Compression is 122-129. Runs smooth and well. Very minor color change around the top edge of head cover temp sensor hole (just the top lip) on driver’s side top cylinder. This cylinder is the 122 cylinder. Tstats pulled and check – opening before “beef rare”. Just kidding – opening about 150 or a little below. Really heavy calcium or lime buildup up in Tstats water jackets. No salt taste at all.

My guess is pull the heads and exhaust cover and clean out the buildup. I’ve never torn into a 2 cycle engine before, lots of Auto engines but no 2 cycles.

What’s your take, anything else I should check and what should I be careful of?

[CentralTexas]

I’m not posting here trying to sell this stuff, but does anyone know anything about Rydlyme marine flush to remove mineral deposits?

[99yam40]

Looks interesting, hydrochloric acid about 10% maybe, looking at MDS sheet. May have some other ingredients.
I have heard of people using a strong vinegar solution and circulating that
I would pull stats before using it to make sure it circulates through heads well
Says to replace internal anodes after using.

If you have never replaced the stats and PRV , I would do that after, or try that before the flush

Let us know how it works for you if you try it and what it costs

[CentralTexas]

I’ll post up some before and after pictures for you. The anodes seem like they might be a problem. It appears from the schematic that the heads have to be pulled to replace them. Does anyone know if that’s true for this motor? That’s one lousy design. One of main things I liked about this approach was not risking broken bolts by pulling the heads. Assuming they get dissolved, what would my downside be if I don’t replace them? This engine is already 23 years old.

[CentralTexas]

I’ve finished flushing my engine with Rydlyme and the results look pretty good. I took some before and after pictures which I’ve attached. I talked to the manufacturer of the product and called a couple of shops that use it. They do recommend replacing the internal anodes and I didn’t want to do that, I’d have to remove the heads. What I did do is run it till 95% of the buildup was gone rather than gun barrel clean. Hopefully the anodes had the same buildup on them as the water jackets and it didn’t eat whatever is left. I didn’t think replacing them was worth the risk of breaking head bolts on a 23 year old engine.

I flushed it with Tstats out for about 1 ½ hours. Total cost was 150.00 including Tstats, gaskets, bilge pump, PRV and Rydlyme. It’ll be about 2 weeks before I get it in the water to see if my overheating problem is fixed. I’ll let you know.

1.jpg

2.jpg

3.jpg

4.jpg

6.jpg

[tonynorie]

Being a DIY'er with an 11 year old motor, this is very interesting considering my motor may benefit from the same treatment. Your results look pretty dramatic. What kind of setup is that you rigged to run the Rhydlime through the water jacket? Good luck when you get it in the water.

[CentralTexas]

Here is what I did:

1) Rydlyme – I used 2 gallons cut with 2 gallons of water.
2) Bilge pump – I bought the cheapest one they had – 500GPH, 12v, $18.00.
3) 2-3 feet of ¾ inch heater hose. It fit the bilge pump but I had to clamp it on the water inlet tube.
4) 2 sets of Tstat gaskets. One for Flushing and checking progress and one to install new Tstats.
5) I used a large mop bucket to hold the 50\50 solution and recycle it.
6) Removed Tstat covers and Tstats. I flushed without Tstats in.
7) Pull lower unit.
8) I pulled the battery from the boat to run the bilge pump. I put my battery charger on the battery so it wouldn’t run down
9) I connected the heater hose from the bilge pump to the inlet tube that goes into the water pump. The solution is then pumping directly into the water jacket.
10) I checked progress 3 time over the 1 ½ hours by pulling the Tstat housing and checking buildup removal.
11) Once I’d gone as far as I wanted I filled the mop bucket with water and flushed X 2.
12) Reassemble with new Tstats and Gaskets.

I’m waiting for the PRV to arrive to replace it and I’ll also check the buildup in the lower part of the water jacket. I also bought an anode from the dealer but it hasn’t arrived yet. I was going to place the anode in the Rydlyme solution as it flushed and see how badly it was eroded but I couldn’t wait. My thought process was – If the anode in the bucket wasn’t badly eroded the anodes in my motor would be fine since they will also be covered with calcium and lime.
Here is a picture of the bucket setup. Good luck if you try it.

016.jpg

[99yam40]

How much $ per gallon was the Rydlyme?

Looks like it did a good job.

I would make sure and run the motor on hose attachment(ears muffs) for awhile also just to make sure it is all out of every nook and cranny

[CentralTexas]

I bought a 5 gallon pail and only used 2 gallons. By the gallon it works out to $28.00, including shipping and sales tax.

[rodbolt17]

are you sure its an overheat and not a restricted remote oil tank filter ?

[CentralTexas]

When the alarm goes off it’s the Temperature light that is lit up on my gauge. I read that this filter will sound the alarm and cut RPM’s if its plugged but I assumed it would be the Oil light that would be lit, not the Temp light.

[CentralTexas]

The Anode I ordered came in today. I dropped it in the same solution I used to flush the engine. It was discolored with some slight surface erosion after 1 ½ hours. No noticeable change in size. In short, the Rydlyme had very little effect on it.

[99yam40]

Now to see if your motor over heat problem is a thing of the past.
Hope it is a thing of the past

[CentralTexas]

Runs like a scalded cat without the screaming. I tested it today, no alarm. My PRV came in and when I changed it out I saw no calcium and lime buildup in the lower water jacket. The Rydlyme really cleaned the system well with a lot less work then pulling heads. I suspect it also cleaned out some of the harder to get to passages better then a tear down and hand clean could have. The internal passages I could see still had the original coating Yamaha put on. The Rydlyme didn’t seem to impact it at all. I’m very happy with the result.

The only problem I ran into was that I accidently pushed the PRV grommet into the water jacket when installing it. Fortunately I’m used to doing dumb sh—like this. Over the years I’ve gotten really good at fishing things out of tight spots with a bent coat hanger.

[99yam40]

Great news about the Rydlyme, thanks for posting your results