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HEY, I JUST BOUGHT THIS BOAT AND WE TOOK IT OUT FOR A CRUISE. IT'S A 1993 BOAT AND MOTOR PACKAGE. IT ONLY HAS 86 HOURS FOR A 12 YEAR OLD BOAT AND WAS GARAGE KEPT. MY PROBLEM STARTED OUT AFTER WE WERE CRUISING, ABOVE 3500 RPM'S THE TEMP ALARMS WENT OFF. I STOPPED AND CHECKED EVERYTHING I COULD THINK OF, EXHAUST WATER TEMP AT THE PISSER, EVEN PULLED THE COVERS AND FELT THE BLOCK. NOTHING OUT OF THE ORDINARY. THE PISSER WATER WAS EVEN COOL. I CHECK WITH THE FORMER OWNER AND HE HAD BOTH LOWER UNITS GONE THROUH RECENTLY WATER PUMPS SEALS ETC. I RAISED THE MOTORS AND CHECKED THAT THE INTAKES HAD NO BLOCKAGE. HAS ANYONE HAD THIS PROBLEM AND WHAT IS IT?
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The "Tell Tale" discharge should always be cool water, that's normal, it should never be hot. IF the waterpumps were in fact replaced just a year ago (receipts?) then I would look at the thermostats and the pressure relief valve in the powerheads for any corrosion or debris blocking them open. With the engines cold when you crank it up on the garden hose flusher do you notice if water flows from the vents above the cavitation plate immediately. If so the thermostats may be stuck open or the pressure relief valve is stuck open dumping all the cooling water out of the powerhead prematurely. Water should not flow out of those vents until the motor is warmed up to operating temperature. Honestly what you describe sounds like warn out waterpump impellers. But if you are sure they were recently replaced it's hard to point a finger at 'em. Did any steam blow out the motors when you got this overheat alarm? The big three items are the waterpump, the thermostats, and the pressure relief valve. Any of that can cause the problem. You can test the sensors with an ohmmeter and a pan of hot water. The overheat sensors close at 183-194 degrees, so throw 'em in a pan of hot water and see when the contacts close, they rarely fail. Use new gaskets when you inspect the thermostats, you can test them the same way you test the overheat sensors. The thermostats open at 140 degrees. Visually watch them in a pan to verify they open. You can drop the lower units and look at the waterpumps to see if it looks like they are fairly new. When in doubt, replace 'em. If you don't have an owners manual and factory service manual for your motor you can get one online from www.YamahaPubs.com, it'll come in handy.
Mike....... Miami, FL -
Sarasotaspeeder,
Since you pulled the cover off and felt of the block and it was warm and not hot, you are probably experiencing the same thing I did last summer with my C115 - bad thermal switch. Hamfisted mentioned it in his post.
There is a thermal switch mounted in each of the cylinder banks on the twin 115 (mine is a 2000 model - I assume yours is similar). The switch is designed to close around 180 degrees farenheit. Probably only one is giving you a problem, so pick port or starboard and test it like Mike mentioned. Mine was closing around 135, so anytime I got above 4000 rpm, the alarm would sound and the electronics would cut back on the spark and shut me down to 1200 rpm. Within a minute or two, the alarm would quit.
You need a fairly accurate thermomter and an ohm meter. You are just looking for continuity at around 180.
Hope this helps.
Ken K
Beaumont, TXComment
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I really appreciate this information. I just ordered a shop manuel, thermal switches, thermostats and gaskets for under $200. I going to change them all just for preventative maintance being possibly 12 years old. Here's a dumb question are these metric?Comment
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Yes everything on the Yamaha is Metric. Get a good set of 6-pt metric sockets and wrenches from Sears, 12-pt sockets can round off bolt heads too easy. Also a good quality 3/8" torque wrench is a must. Torque specs are very important when you're working with aluminum. Pay attention to the specs in the service manual to avoid busting bolts or aluminum pieces. At least you had the sense to get the service manual, it'll pay for itself the first time you avoid taking the thing into the dealer for repair. Good luck.
MikeComment
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Hamfisted,
What brand of torque wrench do you use to service your outboard? I just dropped my lower unit to this past weekend to do the water pump routine, and my Sears 1/2 inch drive torque wrench would not fit four of the seven bolts because of clearance problems. Had to use the ole' calibrated arm and guess at the torque.
I thought about getting a 3/8 drive old deflector style that does not have such a big head on it.
Ken K
Beaumont, TXComment
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Hamfisted,
What brand of torque wrench do you use to service your outboard? I just dropped my lower unit to this past weekend to do the water pump routine, and my Sears 1/2 inch drive torque wrench would not fit four of the seven bolts because of clearance problems. Had to use the ole' calibrated arm and guess at the torque.
I thought about getting a 3/8 drive old deflector style that does not have such a big head on it.
Ken K
Beaumont, TXComment
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Ken, I use a 3/8" beam type or the preset ratchet type. The 3/8" will do just about everything on the motor. But I have 1/2" as well, don't seem to use it much though.
MikeComment
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Well I have recieved my parts and manuel, and getting a torque wrench tonight. But seem to have a few more questions as I get reacquinted with my boat repairs 101? Are the thermal swithes like a simple press-in with a lip. With clean surfaces and new gaskets is a thin coat of silicone a good thing on thermostat housings? I'm thinking about the amount of time my boat sat, indoors 75hours used in 12 years. Was thinking about adding fuel system cleaner to my plastic fuel tank any recommendations or advise on possible problems to look for from long term storage. I'm just starting to get into checking the systems and replacing aged pieces.
Now some food for thought are there simple power upgrades or mods for the 115s being the same motor as the 130s?Comment
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Sarasotaspeeder,
The thermal switches are just plug-in. There is a ridge just outside the hole where they plug in that locks them in place. The switch is pressed into a glob of grease so that when you press it in, the grease will displace any air around it and therefore give the switch good thermal conductivity with the head. Only problem is that when you try to pull the switch out, a vacuum will form behind it. Break the seal of grease around the rubber plug in front of the switch with something like the end of a small tie wrap. That's what I used and it worked ok. Just push the tie wrap in as far as you can between the rubber plug and the metal housing and leave it there while you gently pull on the end of the plug and two wires.
I have yet to replace a thermostat, but looking at my Yamaha shop manual, they do not show using any kind of sealer on the gasket. But I think that a thin film of high temp water resistant grease (like Mobil 1 synthetic) wouldn't hurt. Your not dealing with any high pressure here, just water pump pressure.
If you haven't already done so, I would drain out any old fuel in the tank and drop the fuel filter and clean it. Add Yamaha "ring-free" or
"Seafoam" to your first tank of fuel. The motors haven't enough hours on them to decarbonize. New plugs wouldn't hurt. If salt water was left in the cooling system while in storage, then I would flush with something like "Salt Terminator" or "Salt-Away".
Check the batteries for proper water level in the cells if they are not maintenance free. If they are three or more years old, get new ones.
Check wheel bearings for proper lube.
Can't help you on the 115 to 130 conversion. I have wondered that myself. I would guess it has more to do with carburation and timing than anything else. I'm happy with the performance of my C115 - 47 mph on the water is fast enough for me.
Good luck,
KenComment
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Well all your advice made the job easy to complete. I installed the thermo switches,thermostats and new plugs today. A cordless drill and wire brush helped make clean-up of the thermostat gaskets a breeze. I did notice salt build-up in the housing. Will running in a fresh water lake help remove this or one of those flush treatments better? How long should fresh water rinse be done after boating? After all was done I took a test run and still got my alarms where do I go from here? Did I read something about a rectifier possibly being involved here?Comment
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I always recommend using new gaskets on the thermostat covers, they're cheap and insure a good seal. Used ones eventually leak. I would have doubts about the water pumps if you're still getting an alarm. If they're more than two years old I'd replace them. I think the previous owner's memory might have been a little clouded as to when they were replaced (if ever...). No receipts? No work done....
Mike........ Miami, FLComment
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I did use new gaskets. What I meant was to remove the gasket material left on the surfaces during disassembly. I spoke to the previous owner's mechanic (who I bought the boat through) and he assured me they were changed because he had the alarms go off during transport, then changed them within 2 months. We did a test drive on the boat before purchase for longer than it takes to set them off now and cruised at 4000 rpms during without alarms.
So if we're sure about the thermostats, thermal switches and water pumps (which I am willing to pull down and R&R if need be) What's the next step to track down my problem?Comment
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Sarasotaspeeder,
Man, you have done everything I would have done at this point. Try not to get discouraged - this is how you learn this stuff.
I don't want to insult you, but let's make sure you have replaced FOUR thermal switches total. Not just one per motor. Correct?
When the alarms go off, are there two alarms you hear, and do they go off at approximately the same time? I think I would try running only one engine at a time if you are not sure which alarm is going off. I can't imagine both water pumps being bad at the same time.
Are these 115s premix or oil-injected? If they are OI then maybe the pumps are starving for oil because of restrictions in the lines. If you mix different kinds of oil in the oil reservoirs, a sludge can form from the reaction of different additives of the two different oils - I learned this the hardway, and it shut me down forty miles offshore - had to come in at 1000 rpm on a couple of Suzy 140s.
The salt/sand deposits are in my water jackets also. I used "Salt Terminator" and it helped, but did not remove all of them. Running in fresh water helps; and if your trip has been in salt water you need to flush for a least long enough for your motor to come up to thermostat temp so that the stats will open fully and allow fresh water to flush out that part of the water jacket.
I installed a temp gauge on my C115 and I can see when the stats open, I run for another five minutes after that.
The post about the rectifier/regulator possibly causing an alarm was my response to a problem a fella was having with his digital gauge flashing when the voltmeter was reading 16.2 volts. I was speculating that the regulator was bad and that his digital voltmeter was flashing because it was overranging.
Keep punching at the problem - you will get it fixed. The Yammie 115s are sweet motors.
Good luck,
Ken KComment
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Speeder,
Ok, one last thing to check. The pressure relief valve on each engine. If for some reason they have a heavy mineral buildup and got stuck open, they will release all the cooling water prematurely before the entire powerhead is filled with cooling water. They're a simple inspection. The PRV cover is where that 3/4" hose connects to the back of the powerhead near the bottom. Take out the two 10mm bolts and the cover will pop off. Underneath you'll see a 25 psi stainless spring and the plastic valve itself. Remove all that and inspect the seal and surrounding area for mineral buildup or debri that may be blocking the valve open and preventing a seal. This valve acts as a over pressure relief valve to provide relief at 25 psi. Many times the seal area will get a mineral buildup on it that prevents free movement. Pay attention to the direction the plastic valve is relative to the spring. The short side of the stem faces the spring. The inspection only takes about 20 minutes. But if the valve is getting stuck open you lose your cooling water. Because it sounds like you've covered most everything else.
MikeComment
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