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Not making power...any thoughts please...
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| mtown |
Posted on 08/04/13 - 6:40 AM
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You may have already addressed this in post #13 but I had a similar condition with a 115 Yamaha 2-stroke. There are two small heat sensors that insert into small recessed holes in the block. They have a pink and a yellow wire if I recall correctly. and look kind of like a camera battery. If one is bad it is telling the motor it is overheating and will reduce RPMs. Takes seconds to disconnect and it was my problem, also seconds to replace. They do not make the alarm sound.
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| Tom W Clark |
Posted on 08/04/13 - 8:57 AM
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It could well be the stator, but it is more common on much older motors and much more common on Mercurys than Yamahas.
I went through this with one of my Mercury 150s. It was running very poorly and the mechanic spent a great deal of time trouble shooting until he finally determined bad stator.
It was not able to generate enough voltage to get the switch box to fire off each cylinder and it was exasperatingly intermittent.
The trouble with replacing a stator preemptively is that it is an expensive part and laborious to replace. Be sure you need to do that first.
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| mtown |
Posted on 08/04/13 - 11:58 AM
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Just happened to find a spare of the part I was describing. Yamaha part #688-82560-10. Wires are pink and black.
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| Mtierney |
Posted on 08/04/13 - 8:13 PM
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I thought mine was going into some sort of "safe mode" with no alarm. Sounds like yours is doing something similar. It has done it one other time, since the carb was cleaned, and the mech found a loose spark plug wire, but I am still sceptible about that.
1985 Newport 17 w/ 70 yamaha |
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| dauntless-n-miami |
Posted on 08/05/13 - 1:21 PM
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Thanks mtown for the sensor info, I will investigate to see if my Yamaha 90 uses one and mention it to the mechanic.
Mtierney, the coils and spare plug wires have been exhaustively checked (during cold and hot conditions) and we can't replicate the rpm "drop" issue.
Tom, the stator was checked as well but unfortunately it is not displaying a fault that can be detected as of yet. I too have dealt with Mercury stator issues with some old 200 Black Max's that I had on a previous boat some years ago. Hugh pain to diagnose when they are just beginning to go.
Eagles, the fuel delivery set up on my Dauntless is simple and straight forward and has been functioning for the last 3 years effortlessly. The primer bulb that I had installed 3 years ago is what precipitated the carburetor rebuild when it began to degrade internally and send contaminants into the fuel circuit.
I have extensively inspected and cleaned the entire fuel system (twice) for a fault with none found since the original problem began.
I removed the carburetors yesterday and dropped them of with the mechanic this morning for his review. If no issue is found with the carb's the mechanic offered to accompany me one afternoon this week (after carb's are re-installed) for an on-water test. I drained the fuel from each of the carb's float bowls for an inspection but, was very clean and clear.
I'm hoping that the mechanic does find some fault with my carburetor rebuild rather than the problem turning out to be an intermittent electrical glitch.
Angel M.
1996 Dauntless 15, Sportsman Pkg. - 2007 Yamaha 90 HP 2-Stroke |
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| EaglesPDX |
Posted on 08/05/13 - 6:10 PM
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dauntless-n-miami wrote:
Eagles, the fuel delivery set up on my Dauntless is simple and straight forward and has been functioning for the last 3 years effortlessly.
And may no longer be functioning effortlessly. Easy to grab a portable tank and hook the engine up directly. An cheap and easy test. The fact the engine was dynoed would seem to elimate all the engine issues like the stator, carburetor crossed wires etc. that would show up with an engine under full load.
I'd certainly check out the fuel system as it does sound like fuel starvation occurs when the flow rate goes up.
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| dauntless-n-miami |
Posted on 08/06/13 - 9:51 AM
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Thanks for the input Eagles. When I get to do the next water test I will certainly bring my portable tank along for the "just in case" senerio.
The "Prop Dyno" test has one flaw that the mechanic made me aware of, the outboard will be run for a brief period of 6 to 8 minutes or the motor will begin to overheat due to water flow or lack there of. 2 or less of those minutes will be at full throttle for generating the pressure/load number. If there is an electrical component issue that fails due to operational heat, the brief "dyno" test will not typically uncover it.
So the jury is still out on wether it's an electrical issue. The mechanic has a suspecion that it maybe a fault within what he refered to as the "C.D.I." control box which sits under the voltage rectifier.
Edited by dauntless-n-miami on 08/06/13 - 10:31 AM
1996 Dauntless 15, Sportsman Pkg. - 2007 Yamaha 90 HP 2-Stroke |
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