Temp Alarm went off tonight

[Parker 2310]

Guys, I went out for a ride in the boat tonight because it is the first time it has not stormed in the past week and i am pulling the boat in the morning to do other work. While i was out i was cruising along at 20 MPH with no problem, when i moved it up to 25 MPH the engine started to back down after about 1/2 mile or so. THe temp alarm was sounding off. I took it out of gear and after about 10 seconds the sounder stopped. During that time it was peeing water. I cruised along again at lower speeds and no problem, but when i increased speed it did it again until i stopped. Although it has water coming out, it didn't seem like a strong stream to me. I am having a new hard top and canvas put on this week so it will be pulled tomorrow and i planed on replacing the water pump and thermostats any way because i don't know when / if they were done last as i recently bought the boat. so i am hoping the thermostats and water pump kit will do it. but what about heat sensors, my father was telling me tonight he had a situation like this but it was a bad sensor. Where are they and are they difficult to check / replace?

 

[Parker 2310]

I forgot to say but the engine is a 1999 Yamaha OX66 Saltwater Series 225

 

[TimC2520]

Hi again Walt,

I have the same motor and this past winter I replaced the thermosensor and the 2 thermo switches. I did not have any overheat problem at the time, but I just decided after 10 years and some evidence of corrosion on the plugs, I'll replaced them. The parts are roughly $137 from SIM and it is an easy job. Shouldn't take more than 10-15 minutes as they are plug harnesses and just plug-unplug type of a setup.
I'm not sure if that's your problem, but it may be the first place to look along with replacing the water pump and poppit.
The photo of the thermo sensor is on the stuff I faxed you yesterday, Page #257, diagram 72 (there is an arrow pointing to it). Just use a wrench, unscrew it, unplug the other end and swap out the new one.

The thermo switches are the wires you will see attached to the top of the t-stat cover. Again, it's just a plug at the other end and easy to swap out.
They are also pictured in diagram #72.

Call with any questions and good luck with it.

Tim

 

[Parker 2310]

Great news, after a long day and everything going wrong which required me to work for real vs. work on the boat. I hate the fact that i need to work for a living. Anyway tonight with your help i got the new water pump installed and will do the thermostats in the AM. I checked and the local dealer did not have any sensor alarms so i will have to do them later, but they can clearly be done while the boat is in the water. But the PUMP is done and i an sitting here with a cold one! Thanks again.

 

[TimC2520]

Good job Walt!

 

[TomS]

Check the poppit valve while the boat is out of the water if you can.

-- Tom

 

[Megabyte]

Check the poppit valve while the boat is out of the water if you can.

-- Tom

Correct... water pump, t-stats, poppit.

If you haven't done it in awhile, you might want to give her a SaltAway flush treatment too.

http://www.saltawayproducts.com/ApplicationsPage.htm

Good luck!

 

[Parker 2310]

thanks guys! i have the water pump done and the stats, it is in the shop now getting its new hard top. I will have to do the poppit next week when i get her back. The local dealer didn't have the part so i am going on line tonight to find it and have it delivered directly yo me.

 

[Megabyte]

Give Andy at SIM a call...
http://www.shipyardisland.com/

 

[Bryan 2530]

I second Andy, great to deal with.

 

[Parker 2310]

Well, I changed everything you possibly can and I still got an alarm today. I took the boat out and stayed in the bay to do some trials and actually was going along for quite a while at different speeds. Then I tried to max the speed and after about 1.5 – 2.0 miles the alarm (temp) kicked in and she idled back automatically. To recap what I have already done:

Changed thermostats
Changed Temperature switches (both)
Changed Poppet valve / spring / cover / grommet and hose
Ordered new temperature sensing unit (but this wouldn’t effect the alarms, as I read it, it is designed to monitor and assist with the air/fuel/oil mix on EFI, but ordered it anyway)

I even put in new plugs while I was working on it. I have a good flow of water coming out during all staged of testing. The engine runes fine at idle up through 3000 RPM. But when I attempted to run at rpm of apx 4000 after about 1.5 - 2.0 miles the alarm (temp) goes off and the engine throttles back. I can then clear the alarm within seconds by running the engine in neutral and pumping the water through it. I don’t see any steam or other indicators of overheat.

Today I bought "salt away" and I am going to run it through the system for the next few days like they advertise and see what happens.

I am open to any and all suggestions. At this point all I want to do is fish and the motor is taking all my time. Any thoughts?


Walt

 

[TimC2520]

Hi Walt,

Are you positive it's the temp alarm and not some other alarm? i.e. oil?

 

[Parker 2310]

It is the temp alarm, as i noted it flashing. i took the boat out again tonight after using salt away and i was able to run at 3900 / 4000 rpm which is about 25 MPH and did nopt have a problem at all. when i pushed it to 4500 and moved towards 30 MPH then the alarm went off after 1.5 miles. I am going to flush it daily for the next few days and see if i can break up any more interior salt.

 

[TimC2520]

Hi Walt,

I've gone through this service manual over and over again for you.
Aside from the water pump, t-stats and poppit, there is not much else to look for. If there is no problem with those, it does go on to say that "rocks, pieces of failed water pump impeller, sand, shells and other debris may be restricting water flow. Salt, calcium and other deposits can form in the cooling passages and prevent efficient heat transfer. "

Salt-Away may be your next step.

 

[Parker 2310]

I am on day three of the salt away treatment program. I plan to try again tomorrow evening, weather permitting, and see how it goes. I will get back with you.

 

[Parker 2310]

Ok, here is the deal. I replaced everything that can be replaced on the cooling system and have flushed the system daily every 24 hours as described using Salt Away. After 4 days of flushing the system and changing all parts I took the boat out tonight. After allowing it to warm up, I drove for approximately 3 miles at 5000 rpm's and the temp alarm went off and throttled down the engine. I immediately put the engine in neutral and increased the RPM' above idle and the engine cooled within seconds and the alarm stopped.

So I decided to test the engine at different speeds. The next test was done at 4500 RPM's and the alarm again went off after 3 miles. Next I ran the boat at 3900-4000 rpm's and the boat ran fine and smooth for the rest of the night. I put on a total of 11 miles at that speed before I returned to the pier. So the alarm never went off at 4000 rpms and the boat was running at about 20-21 mph according to the speed gage or 25-26 mph according to the GPS depending on what gage you look at.

The biggest thing that I must admit is that before I used the salt away, the engine would never have run for three miles at 5000 rpms much less for 11 miles at 4000 rpms. So for now I am going to continue the salt away treatment and see if it continues to help. My engine is the saltwater series 225 V6 and has a hose bib that screws in under the cover and is the method recommended to flush the engine. Is there another way of flushing it with the salt away that may allow the treatment to get inside around the t-stats that I am sure are closed with the cold water.

Anyone out there have any other thoughts about what more I can do in this case. I would like to be able to go over 25 mph if possible.

 

[TimC2520]

Hi Walt,

You may want to run this by Andy at SIM, he also has a forum over on the hulltruth. The guy knows these and all Yamaha's motors like the back of his hand. He is extremely helpful and a good guy to talk to.

I use that hose attachment to flush mine after every use and have been for 11 seasons now. I was once told that the water does not make it up as high as the t-stats but I never was able to confirm that. I wonder if you could remove the t-stats and fill those openings with salt-away and let it sit. :?:

Another option would be the i-boats website for Yamaha questions. There is a guy over there who goes by the name of "rodbolt" and he too is a genius with these motors and very willingly answers trouble shooting questions. Good luck with this and keep us posted.

Tim

 

[TimC2520]

Walt,

Any updates on this problem?

--Tim

 

[Birdman328]

is the top of the motor actually feeling hot to you? or is it just the lower unit that feels hot to you? could be a lower unit problem maybe???

 

[Parker 2310]

tim,

sorry for the delay. I took off the past few weeks and have dine nothing but go out fishing every day. I have been going off shore as far out as 40 miles to the fist canyon and been catching fish. THe alarm has not gone off at all and i have not gone over 4500 RPM's. the bottom line in with the average weather condition out there is it hard to go more the 25 MPH anyway. so i tend to average 25 - 28 MPH heading out and have not had a problem. I have continued to use SALTAWAY daily and it really does work. I think i will try a high speed test this week in the bay and see what happens. I spoke to a friend here at the marina and he told me about his old Yamaha and that the alarms went off for temp and after changing everything he had to replace the ZINKS in the head cooling passages. I had not heard of them and looked at the book i bought and they show two zink's in each head cooling passage but you have to remove the heads to replace them. So if at all, that will be a winter project. In the mean time I have put on over 500 miles in the past two weeks of fishing off shore and had no problems.

Walt