1986 115ETLJ POWER LOSS! IS IT THE WATER FILTER PROBLEM?PLS HELP:(

[RuNNeR]

HI HOW IS EVERYBODY,MY MOTOR HAS PROBLEM AGAIN!! it was happen after motor run about 45 mins, and then stop for other 30 mins, and then run about 20 mins,and then suddenly the motor was loss power and rpm was drop down to 800,so i was put the control back to neutral and put forward again then the motor was dead!so i started the motor again and every thing just back to normal,run about 5 mins,samething again!and then happen 3 time after,i took off the build in fuel tank hose with vapor filter and plug in the 2nd w/o vapor filter removable tank,and then all run good~_~ so is it mean need to replace the filter?my filter beem replaced, but it beem uesd about over 150L of fuel through that filter already,is time to replace again? also fuel pump replaced plugs replaced 2cyc oil full and the carbs was cleaned very nice start right the way and whatelse it could be! if you guys have any idea please help..please help

Thanks in advance for any help ..........pls

/2uNNe/2

[RuNNeR]

I wonder is my motor have o2 sensor? if it does ,should i replace it please let me know

thanks again [img]smile.gif[/img]

[Ken]

Runner,
It sounds like you have already found the problem - plugged up filter in the fuel tank, right?
You may have gotten a fill of contaminated fuel, or if you have recently started using an ethanol blended fuel, then that may be where the clogging is coming from.
The ethanol in blended fuel will break loose deposits in the fuel tank and hoses that pure gasoline won't. If you have a fiberglass tank, then you really need to be concerned. Take a look at this article about ethanol fuel:

http://www.boatus.com/news/e10_0706.htm

Yamaha has recently come out with a service bulletin recommending the addition of a 10 micron fuel filter/water separator in the fuel line to combat the ill effects of ethanol.
If you suspect contaminated fuel in the tank, then you need to drain it completely and add fresh fuel and check the tank filter again. If your tank hose has an anti-siphon valve attached at the tank output, then it also may be sticking on you. Either replace or eliminate.
I do not believe your 115 has an O2 sensor - I don't think any of the Yamaha V-4 2-strokes do.
You will find the O2 sensor on the fuel injected models.
Good luck [img]smile.gif[/img] ,
Ken K

[RuNNeR]

Hi Ken, thxn for your reply, it's really appreciated.

Actually, it was a 1979 boat, and I am not too sure whether it has a fibreglass tank or not. Anyways, I will try to drain out all the fuels and replace the filter more often. I will see how it goes and will let ya know. Wish me luck and thanks again! [img]smile.gif[/img]

[RuNNeR]

HI KEN AND EVERYONE,how are you guys doing? (sorry for the lengthy

message but please do read it, thx!)

My motor has the same problem again!! However, I think it might not be

the water separator or contaminated fuel problem because I have already

replaced a new water separator but the same problem still occured when

I was using the small removable red tank.

I am thinking that if the filter is full of water inside or gets

clogged, the motor will be totally dead, am I right? In my case, the

problem was like a power loss and RPM dropped to 800 RPM but it was not

dead. Then when I put the control back to neutral and put forward

again (accelerating), then the motor died!! So i think it's unlikely

to be contaminated fuel or water problem, right?

My motor usually runs fine during the beginning 30 mins,and then the

RPM starts to drop a little. For instance, the motor is running at

around 4000 RPM, then it will drop about 500 RPM (or more) to around

3000-3500 RMP after 30 mins.

Also, the RPM dropped all the way to 800 RPM when I was passing a

couple of bigger waves. Would that because of the following reason?

When the boat was passing the crest of the wave, the motor had to run

harder in order to pass the wave. But when the boat was passing the

trough of the wave, the motor ran smoother compare to crest passing.

So at that time, in order to prevent the motor itself from overheating,

the motor was automatically turned into safe mode which lead to the

decrease of RPM (but the alarm buzzer wasn't on in my case). So do you

guys think it was an overheating case? and the buzzer was not working

properly? How do I check and confirm that the buzzer works? Actually

I don't really know what safe mode means, haha!

If the "safe mode got turned on automatically" was indeed the problem

in my case, how to resolve this problem or any other ideas?

You guys' inputs are very appreciated and thank you very much in

advance for the help!

[Ken]

Runner,
You may be having problems with the fuel pump - if it is at least five years old, I would replace it (not very expensive - check boats.net, sponsor of this forum).
You can check the alarm by shorting out the two wires that go to the thermo switch in the head - port or starboard, there is one is each head.
There will be "bullet" connectors about five inches away from the thermo switch - disconnect both and short the two that go back to the CDI with the ignition on (motor not running). The alarm should sound immediately - if not, then you have a bad alarm/wiring.
When your motor goes into rpm reduction (safe mode) due to either overheating or low oil, the alarm should sound and a few seconds later the motor will start to shake violentily because the CDI has cut back on spark. You throttle back to neutral, and the motor will idle fine - the operator is suppose to determine the problem at this point [img]smile.gif[/img] .
I don't think you have a fuel filter/delivery problem since your motor will run fine for first 30 minutes. I would replace the fuel pump, as noted above, and go from there. You may have a thermal problem with the CDI , but hopefully not.
Good luck, and let us know what you find out [img]smile.gif[/img] ,
Ken K

[RuNNeR]

Hi Ken,

Thanks for your reply. Unfortunately, my fuel pump was replaced a month and half ago (the new fuel pump was an OEM one). So, I think it s unlikely to be the fuel pump problems. What else do you think that it might cause these problems? Any ideas? Do you need further info about my problems in order to see what the problem is?

Thank you again and your help is very much appreciated.

RuNNeR