Oil tank is coming off

[boatnamesue]

Cool tool. If i use that, is there a temperature that is normal operation for a head or would i just compare the two to see which one is hotter?

According to the thermo-switch specs I previously included, the switches are grounded (discontinuity) during normal operating temperature, 140º-165º.  So that's a good indication of the temps to expect on both banks if engine is not overheating.  Any temp above 165º the switches become continuous, thereby sending the signal to CDI causing alarm to sound.

The 2 banks won't read the exact same temps when the engine is warm.  It's normal if there is 10º-15º difference.  What you'll be looking for is the bank or both banks reading temps >165º, if indeed the engine is overheating.

[clop52]

You are correct. I do have a tachometer and the overheating alarm was going off, not the low oil alarm. These are the steps I took that led me to believe that the problem was in the oil system:
-As soon as the alarm started going off, the engine didn't automatically bug down, I manually slowed it down to less than 1000 rpm before the alarm would shut off.
-I checked the pissing strength -which I know now not to trust- and it seemed ok.
-Removed the cowling and checked the oil on the tank and it was full.
-Touch the heads and were not too hot, just warm. That made me rule out water pump.
-My hyphothesis was that maybe the engine was not getting enough oil since the alarm would only sound off when I sped up too quickly and it wouldn't when I sped up incrementally, up a certain point. Once I reached 4000 rpm, the alarm would sound off.

Let me know if my hyphotesis is wrong.

What I'm going to do:

-Check Outter tank pump. 12 volt test. Reintall.
-Reinstall inner oil pump, bleed.
-Check poppet, clean and reattach.
-Check thermostats. (What do I look for on those?)

Thanks again for all your input, I'm getting a lot better at all these. Don't like buying new...too boring.

You have the old old style yam tach, which does not include the visual high temp alarm.  I believe that model of tach was paired with the yam speedometer that did have the temp symbol.  So in your case, if you're getting an alarm and no bars are flashing over the oil symbols it's safe to assume the alarm you hear is caused by high temp.  It's also possible the alarm you're hearing is due to low voltage, and this alarm would not cause limp mode.

I would go about troubleshooting by first testing both alarms to verify proper function, this will rule out the possibility of false-positive alarm activation.  Test oil alarm as followed:
*Drain main tank oil level to below the tank's bottom level line.  Turn key to ON position.  Alarm should immediately sound and you should see all 3 bars blinking over the 3 oil symbols on tach.  Refill main tank.
*Drain reserve tank.  Turn key to ON position.  Alarm should immediately sound and you should see 1 solid bar on left and 1 blinking bar over middle symbol on tach.  Refill reserve tank.
*If one or both of the above actions does not cause alarm, the oil sensor(s) is bad.

Test thermosensors as followed:
*Each engine bank has a thermosensor with 2 pigtail wires coming out of it.  Disconnect these 2 wires from the engine side wires, then connect together the 2 engine wires.  Turn key ON.  Alarm should immediately sound.  Repeat the same test on other bank. 
*Test each thermosensor by using the instructions in the below attachment.



Here is the procedure for checking function of stats:





If you've confirmed both oil and temp alarms to be functioning properly, now you can dig into the issue causing the alarm...which I recon to be high temp.  You described the alarm will sound when quickly throttling up, but will not alarm if you slowly increase throttle.  To me this sounds like there is an area within the cooling system within 1 or both banks that is blocked by corrosion.

Once you've checked stats, confirmed alarm function, etc., I suggest pulling the head covers off to inspect cooling system.  It's a simple and fairly quick procedure, so long as you don't snap a head bolt.  If you haven't removed the head bolts since owning engine, no telling how long it's been since these bolts have been backed out.  You probably will encounter a stuck bolt considering the engine age.  Just be very gentle when backing these bolts out.  If you're trying to back one out and it won't budge, stop.  Get some PB blaster or likewise and spray bolt.  Let it sit a minute, then try again.  If this doesn't work you can then resort to heat cycling the bolt.  This does the trick 99% of the time if done carefully.

Once the head covers and heads are off plan on replacing the gaskets.  Don't reuse the old ones unless you just recently replaced.  I'm reckoning you're gonna encounter a lot of passages with corrosion.  And that's when the real labor begins.  We'll touch on that if need be.

All right. So this is how is going so far:

-Checked both oil tanks. Alarm sounded when tanks were below the minimum line and the low oil light was flashing. Good.
-Checked both sets of thermo-sensors by linking the pig tails together, alarm sounded.
-Opened the thermostat cover and...this is how it looked like:


-The t-stat did not come out as easily as it should.  I had to pry it out.  I tore up part of the seal in the process.  This is what it looked like after:



For sh!ts and giggles, i did the hot water test, and they worked.  However, i wonder if their movement was restricted because of all the junk in there? I ordered two t-stats today and they should be here Friday.

I have three questions:

1-What is the most effective way to clean the salt deposits from inside the thermostat housing?
2- I use my boat in salt water almost exclusively.  Does a product called "Salt-Away work?
3- I have not been able to remove the thermo-switchets yet.  I am afraid that if i pry too hard i'll break them. Recommendations?

3.5 I do not want to see what is under the head covers...but i think i should.  Thoughts?

Looks like my "oil system problem," wasn't.  I stand corrected. 

[boatnamesue]

Ok, great job so far.  Good news is both alarms are functioning appropriately.  Bad news is the corrosion you see in the stat housing is a spot-on indication of the corrosion inside the cooling system.  So the alarm that has been activating is the high temp alarm.  If the stats opened when you tested, and you didn't clean them before testing, I'd recon they were also operating when installed.  If the stats were full of junk that you cleaned out prior to testing, it is possible they were not functioning...which would cause overheating.  Be that as it may, what you see in the stat housing is what's happening in the cooling system.  So even if the cause of alarm was due to failed stats, it would only be a matter of time before the cooling system shuts down from corrosion.  Meaning...time to pull the heads.

I've included a few photos below.  The 1st is a cross section of the cylinder head for a '93 115hp.  I'm not 100% this schematic is exact to your engine, but if you reply back with your complete model number I'll verify.  The other 3 pics are examples of what you'll see when heads are pulled.  These are mine that I pulled last year.  I too have a yamaha 115hp, 1998. 

If you choose to pull heads, go ahead and order 2 each of head gaskets and head cover gaskets before you start so you'll have these prior to labor.  All in all it's a simple and not so labor intensive job to pull off the head covers and heads.  Having these removed will also allow you to visualize the cylinders and piston heads, as you can see in the picture.   I think you've got 12 cover bolts and 10 head bolts for each bank. 


1-What is the most effective way to clean the salt deposits from inside the thermostat housing?
Wire brush.  If there are deposits rock hard they can be gently chipped away using a screwdriver, tap, or likewise. 

2- I use my boat in salt water almost exclusively.  Does a product called "Salt-Away work?
I know some who use this product regularly and swear by it.  However, from what I've read about this product it's more for preventative maintenance.  In your case, the corrosion has already formed large deposits.  So I'm not so sure you'd have complete success using this product.  Though it's worth a try flushing some through your system....if the engine won't overheat.  If it does overheat, the option of using salt-x is a moot point.

3- I have not been able to remove the thermo-switchets yet.  I am afraid that if i pry too hard i'll break them. Recommendations?
Maybe wiggle it, pry it a little, turn it a little.  But you're right, don't force it.  I didn't pull the switch when I cleaned my cooling system and I have no issues. 

3.5 I do not want to see what is under the head covers...but i think i should.  Thoughts?
Yes.  Though not everybody maintains their outboard as I do.  Most just run their engine until something bad happens, then deal with the issue.  I do the opposite, keep up the maintanence so I don't encounter issues.  But it's your call.  You can try salt-x or other products out there that claim to dissolve salt deposits.  There are even homemade solutions I've read that work just as well.  I wanna say dish soap, I think. 

I can understand the hesitation to pull the heads...that being running the risk of snapping a head bolt.  I refer back to my previous post concerning the undertaking of backing out head bolts.  Also, when possible use a wrench.  When it's not possible use a low profile metric socket, not a long one.  When head bolts are torqued, a long socket extension is used because the longer the articulating arm the more easily torque can be applied.  However, when backing out bolts you want the opposite effect....you want a short articulating wrench or socket arm.  Because the closer your hand is to the bolt, the better you're able to get a feeling when the bolt is beginning to loosen.  Or when it's not loosening.

[Capt. Bob]

Did you also order the PCV/poppit valve?

Again, my experience (I'm a land surveyor not a boat mechanic) is that my Yamaha overheated at speed due to a faulty poppit valve.

Let me ask; do you flush your engine after use on "muffs"?
If so, do you see the thermostats opening and water flowing out the lower discharge over the ventilation plate?
Like this?


Good luck.

[boatnamesue]

I have not been able to remove the thermo-switchets yet.  I am afraid that if i pry too hard i'll break them. Recommendations?

After more thought I want to modify my earlier suggestion regarding the removal of the PCV.  Refer to the picture below, #22 is the PCV.  Unlike threaded head bolts, the PCV is a plastic stem that inserts into a rubber grommet.  The PCV housing needs to be removed (#26) with it's 2 bolts (#27).  You shouldn't have a problem or the same concern backing these bolts out compared to head bolts because the 2 PCV housing bolts do not undergo the same amount of high temp exposure as the head bolts do.  Once you've removed the bolts, housing, gasket, and spring, you should then only have to pull/pry up the PCV out of the grommet. 

The 2nd picture I've attached is a general description of the PCV and its function.

[clop52]

Gentlemen, thanks for your responses.
I will do just as you recommend, Jason. I’m getting the thermostats today, so I will install those and run some salt-away to see if I can loosen some of salt. I’m ordering the gaskets and popping valve today as well.

Capt Bob, I do flush my motor after every outing, usually for about 10 minutes or so. I don’t think no the two previous owners were as diligently as I am, though.

My engine model is 115TLRR

I will remove the heads as soon as the parts get in, so probably Monday or Tuesday.

More to follow...have a great weekend!

[boatnamesue]

If you don't already have the service manual for your engine you're in luck.  Good to have as a guide.  Here is a pdf link for a '93 115TLRR:

https://www.vansoutboardparts.com/service-manuals/yamaha-service-manuals/1993-yamaha-shop-manuals/604-1993-yamaha-115r-130r-150r-175r-200r-225r/file

[boatnamesue]

I highly recommend registering on the yamaha outboard parts forum.  There are a few regular members who are yamaha master marine mechanics, few other members who just know everything about how to fix em.  If you end up registering and submitting a question, be sure to start the initial thread with your engines model and year.  Here is the web address:  http://www.yamahaoutboardparts.com

I came across a thread on the yamaha forum where a member used citric acid to clean the water passages inside the head.  From the pictures he posted it looks like it worked very well.  Here is the thread:   http://www.yamahaoutboardparts.com/forum2/wot-overheat-94-prov-115hp-th27868.html

[clop52]

I’ll definitely register and check it out. Thanks! Citrix acid? Interesting. I bought the salt-away stuff today. On the bottle it does say that it will remove salt built-up, but over a period of 2-4 days. It comes with a contraption where you put the solution in and then it’s hooked up to a garden hose and ear mu ffs to  flush the engine for 30 seconds.  You wait  24 hours in between flushes and avoid salt water in the mean time. I’m going to give it a try and see what happens.

[boatnamesue]

I’ll definitely register and check it out. Thanks! Citrix acid? Interesting. I bought the salt-away stuff today. On the bottle it does say that it will remove salt built-up, but over a period of 2-4 days. It comes with a contraption where you put the solution in and then it’s hooked up to a garden hose and ear mu ffs to  flush the engine for 30 seconds.  You wait  24 hours in between flushes and avoid salt water in the mean time. I’m going to give it a try and see what happens.

If possible, you may want to consider hooking up dual flushes.  One hose for ear muffs and another hose attached to the powerhead flushing hose.  Run water thru hoses simultaneously when engine is on.  This might help keep the engine from overheating, if this becomes an issue.  If you live near a public boat ramp, there usually are multiple water spigots for washing down boat/motor.  Or if you live in a house with a outside spigot, your neighbor probably has one too. 

[clop52]

i don’t think my boat has a second place to attach a hose in order to flush the heads. Does it? I’ve seen the ones that newer outboards have, but i’ve seen one on mine...

[Capt. Bob]

Capt Bob, I do flush my motor after every outing, usually for about 10 minutes or so. I don’t think no the two previous owners were as diligently as I am, though.

My question was, when you flush, do you notice the T-Stats opening after a short while once the motor warms up?

[clop52]

Capt Bob, by “noticing the t-stats opening,” do you mean that if we notice the water pressure coming out of the pisser increases? If so, yes. If that is not what you meant, then should I physically observe the t-stats opening and closing while flushing?

[Capt. Bob]

When you first start your motor on the muffs, it takes a short time at idle to reach operating temperature. During this time, you will (should) notice water coming out of the "pisser". T-stats that are operating correctly will be closed during this early stage and no water will be coming out the lower discharge vents on each side of the lower unit, just above the ventilation plate (see reply #18 in this thread). As the motor reaches operating temp range, they will open which allows additional circulation of water and thus maintains the temperature in its designed operating range. The additional water is discharged through the vents mentioned above (again, a pic showing this is located in reply #18 of this thread).

I mention this because I personally monitor this action when I first start my motor on the flushing muffs. It allows me to see that the T-stats are operating correctly(since I presently don't have x-ray vision). If they don't open after a minute or so, I shut down. If the flow appears weak, I replace the stats. It's just another check that I have used for many years.

[boatnamesue]

i don’t think my boat has a second place to attach a hose in order to flush the heads. Does it? I’ve seen the ones that newer outboards have, but i’ve seen one on mine...

My mistake.  The powerhead flushing port was a new feature beginning in '98 for 115hp engines.